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Exploration Of Mars

85 posts in this topic

MIT observations give precise estimate of Mars surface ice



The Massachusetts Institute of Technology press release is reproduced below:

linked-image
This image of Mars' south polar region shows the ice cap (in white) within the smooth
polar layered deposits that overlie the cratered southern highlands.
Image courtesy / NASA/MOLA Science Team


September 21, 2007

An MIT-led team of planetary scientists has found that the southern pole of Mars contains the largest deposit of frozen water in the inner solar system, outside of Earth.

The new results show that water, not carbon dioxide, is the predominant frozen liquid found in the southern polar region of Mars, said Maria Zuber, MIT professor of geophysics.

Zuber said scientists have suspected that the southern polar cap of Mars is comprised of a thin veneer of carbon dioxide that rests atop a layer of dust and ice. However, scientists have also observed a surrounding area much larger than the polar cap that is dark and smooth, and it was uncertain whether that region was also composed of dust or ice--or both.

"What we found is that water ice is the dominant constituent beneath a thin dust veneer," said Zuber, lead author of a paper on the work appearing in the Sept. 21 issue of Science.

Ever since carved channels were first observed on the surface of Mars, scientists have suspected that water once flowed across the surface.

Scientists also wondered whether the Martian poles held large reserves of water. However, because the Mars atmosphere is 95 percent carbon dioxide with only trace amounts of water, some researchers theorized that the polar caps were frozen carbon dioxide, or dry ice.

Zuber's team identified the composition of the southern polar cap by calculating its density. Their results show the density of the polar cap as well as the surrounding smooth layered deposit region is about 1,220 kilograms per cubic meter, which indicates that it is made of mostly water, with about 15 percent silicate dust mixed in.

(The density of water ice is 1,000 kilograms per cubic meter, and the density of dry ice is 1,600 kilograms per cubic meter.)

Zuber and her colleagues used topographical and gravitational data gathered by three Mars orbiters to find the volume and mass of the ice cap, allowing them to calculate its density.

"It's a really simple experiment but you have to measure things very precisely," Zuber said, who is head of MIT's Department of Earth, Atmospheric, and Planetary Sciences.

The experiment reveals that the southern Martian polar region is the largest body of frozen water on the planet and the largest, outside of Earth, in the inner solar system, which includes Mars, Earth, Venus and Mercury.

Until now, scientists were puzzled by the observation that a large percentage of the southern polar region surface does not reflect much light, as it would if there were ice on the surface. This study shows that much of the ice is covered in a layer of dust, but it remains unknown why the dust only covers certain areas, Zuber said.

She plans to undertake a similar density study of the northern polar cap, which does not appear to have a covering of dust, but which is abuts against a large apparent dune field that is not now thought to contain significant ice.

Zuber is the lead investigator for gravity for the Mars Reconnaissance Orbiter, and deputy principal investigator for the altimetry experiment aboard the Mars Global Surveyor. The team also used data from the Mars Odyssey satellite.

Such collaborations between teams "really increase the value of what any single experiment could show on its own," Zuber said.

Jeffrey Andrews-Hanna, an MIT postdoctoral associate in the Department of Earth, Atmospheric and Planetary Sciences, is also an author on the paper. Other authors are Roger Phillips of Washington University; Sami Asmar, Alexander Konopliv, Jeffrey Plaut and Suzanne Smrekar of the Jet Propulsion Laboratory at Caltech; and Frank Lemoine and David Smith of the Planetary Geodynamics Laboratory at the NASA Goddard Space Flight Center.

The research was funded by the NASA Mars Program.[/font]

Source: MIT Press Release

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Hawaii Reveals Steamy Martian Underground
10.17.07


Is Mars dead, or is it only sleeping?

The surface of Mars is completely hostile to life as we know it. Martian deserts are blasted by radiation from the sun and space. The air is so thin, cold, and dry, if liquid water were present on the surface, it would freeze and boil at the same time. But there is evidence, like vast, dried up riverbeds, that Mars once was a warm and wet world that could have supported life. Are the best times over, at least for life, on Mars?

New research raises the possibility that Mars could awaken from within -- three large Martian volcanoes may only be dormant, not extinct. Volcanic eruptions release lots of greenhouse gasses, like carbon dioxide, into the atmosphere. If the eruptions are not complete, and future eruptions are large enough, they could warm the Martian climate from its present extremely cold and dry state.

linked-image
Image above: This is a shaded relief image derived from Mars
Orbiter Laser Altimeter data, which flew onboard the Mars
Global Surveyor. The image shows Olympus Mons and the
three Tharsis Montes volcanoes: Arsia Mons, Pavonis Mons,
and Ascraeus Mons from southwest to northeast.
Print-resolution copy
Credit: NASA


NASA-funded researchers traced the flow of molten rock (magma) beneath the three large Martian volcanoes by comparing their surface features to those found on Hawaiian volcanoes.

"On Earth, the Hawaiian islands were built from volcanoes that erupted as the Earth's crust slid over a hot spot -- a plume of rising magma," said Dr. Jacob Bleacher of Arizona State University and NASA's Goddard Space Flight Center in Greenbelt, Md. "Our research raises the possibility that the opposite happens on Mars - a plume might move beneath stationary crust." The observations could also indicate that the three Martian volcanoes might not be extinct. Bleacher is lead author of a paper on these results that appeared in the Journal of Geophysical Research, Planets, September 19.

The three volcanoes are in the Tharsis region of Mars. They are huge compared to terrestrial volcanoes, with each about 300 kilometers (186 miles) across. They form a chain heading northeast called the Tharsis Montes, from Arsia Mons just south of the Martian equator, to Pavonis Mons at the equator, to Ascraeus Mons slightly more then ten degrees north of the equator.


linked-image
Image above: Four images showing examples of lava tubes and
lava channels on Earth. Upper left: A skylight looking into an
active lava tube on KilaueaVolcano, Hawaii. Upper right: A
collapsed lava tube located within the Snake River Plains,
Idaho. Both lower images show lava channels on Kilauea
Volcano, Hawaii.
Print-resolution copy
Credit: Chritina Heliker (color images) and Ron Greeley
(black and white image)


No volcanic activity has been observed at the Tharsis Montes, but the scarcity of large impact craters in the region indicates that they erupted relatively recently in Martian history. Features in lava flows around the Tharsis Montes reveal that later eruptions from large cracks, or rift zones, on the sides of these volcanoes might have started at Arsia Mons and moved northeast up the chain, according to the new research.

The researchers first studied lava flow features that are related to the eruptive history of Hawaiian volcanoes. On Hawaii (the Big Island), the youngest volcanoes are on the southeastern end, directly over the hot spot. As the Pacific crustal plate slowly moves to the northwest, the volcanoes are carried away from the hotspot. Over time, the movement has created a chain of islands made from extinct volcanoes.

Volcanoes over the hot spot have the hottest lava. Its high temperature allows it to flow freely. A steady supply of magma from the hot spot means the eruptions last longer. Lengthy eruptions form lava tubes as the surface of the lava flow cools and crusts over, while lava continues to flow beneath. After the eruption, the tube empties and the surface collapses, revealing the hidden tube.

As the volcano is carried away from the hot spot, magma has to travel farther to reach it, and the magma cools. Cooler magma makes the lava flow more slowly compared to lava at the younger volcanoes, like the way molasses flows more slowly than water. The supply of magma is not as steady, and the eruptions are shorter. Brief eruptions of slowly flowing lava form channels instead of tubes. Flows with channels partially or completely cover the earlier flows with tubes.

linked-image
Image above: Shuttle Radar Topography Mission (SRTM) shaded
relief image showing the five shield volcanoes of Hawaii, which
increase in age to the northwest. Lower images show the typical
lava flow types for Mauna Loa (left), and Kilauea (right). At
Mauna Loa, rough, channel-fed flows have become more common
products of recent eruptions, and they surround and cover the
older, smooth, tube-fed flow surfaces. The surface of Kilauea is
dominated by smooth, tube-fed flows, which are the most common
flow structure resulting from recent eruptions.
Print-resolution copy
Credit: NASA and Jacob Bleacher


As the volcano moves even further from the hot spot, only isolated pockets of rising magma remain. As the magma cools, it releases trapped gas. This creates short, explosive eruptions of cinders (gas bubbles out of the lava, forming sponge-like cinder stones). Earlier flows become covered with piles of cinders, called cinder cones, which form around these eruptions.

"We thought we could take what we learned about lava flow features on Hawaiian volcanoes and apply it to Martian volcanoes to reveal their history," said Bleacher. "The problem was that until recently, there were no photos with sufficient detail over large surface areas to reveal these features on Martian volcanoes. We finally have pictures with enough detail from the latest missions to Mars, including NASA's Mars Odyssey and Mars Global Surveyor, and the European Space Agency's Mars Express missions."

Using images and data from these missions, the team discovered that the main flanks of the Tharsis Montes volcanoes were all alike, with lava channels covering the few visible lava tubes. However, each volcano experienced a later eruption that behaved differently. Lava issued from cracks (rifts) on the sides of the volcanoes, forming large lava aprons, called rift aprons by the team.

The new observations show that the rift apron on the northernmost volcano, Ascraeus Mons, has the most tubes, many of which are not buried by lava channels. Since tube flows are the first to form over a hot spot, this indicates that Ascraeus was likely active more recently. The flow on the southernmost volcano, Arsia Mons, has the least tubes, indicating that its rift aprons are older. Also, the team saw more channel flows partially burying tube flows at Arsia. These trends across the volcanic chain indicate that the rift aprons might have shared a common source like the Hawaiian volcanoes, and that apron eruptions started at Arsia, then moved northward, burying the earlier tube flows at Arsia with channel flows.

linked-image
Image above: This figure shows two examples of younger lava
channels that buried older lava tubes on Mars. The boundary
between the rougher appearing lava channels and the
smoother appearing lava tubes is outlined in black. Image A
was taken by the High Resolution Stereo Camera (HRSC)
onboard the European Space Agency's Mars Express and
image B was taken by the Thermal Emission Imaging System
(THEMIS) onboard NASA's Mars Odyssey spacecraft.
Print-resolution copy
Credit: ESA and NASA


Since there is no evidence for widespread crustal plate movement on Mars, one explanation is that the magma plume could have moved beneath the Tharsis Montes volcanoes, according to the team. This is opposite to the situation at Hawaii, where volcanoes move over a plume that is either stationary or moving much more slowly. Another scenario that could explain the features is a stationary plume that spreads out as it nears the surface, like smoke hitting a ceiling. The plume could have remained under Arsia and spread northward toward Ascraeus. "Our evidence doesn't favor either scenario, but one way to explain the trends we see is for a plume to move under the stationary Martian crust," said Bleacher.

The team also did not see any cinder cone features on any of the Tharsis Montes rift apron flows. Since cinder cone eruptions are the final stage of hot spot volcanoes, the rift apron eruptions might only be dormant, not extinct, according to the team. If the eruptions are not complete, and future eruptions are large enough, they could contribute significant amounts of water and carbon dioxide to the Martian atmosphere.

linked-image
Image above: This figure shows two examples of volcanic cones.
Image A was taken by the High Resolution Imaging Science
Experiment (HiRISE) Onboard NASA’s Mars Reconnaissance
Orbiter. This image shows a cone on the southern main flank
of Pavonis Mons. Image B is taken from Google Maps, and
shows SP crater in northern Arizona, near the town of
Flagstaff.
Print-resolution copy
Credit: NASA and Google, Inc.



Bill Steigerwald
NASA Goddard Space Flight Center


Source: NASA/GSFC - News

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Mars' Molten Past


The University of California Davis press release is reproduced below:

November 21, 2007

Mars was covered in an ocean of molten rock for about 100 million years after the planet formed, researchers from the Lunar and Planetary Institute in Houston, Texas, UC Davis, and NASA's Johnson Space Center have found. The work is published in the journal Nature on Nov. 22.

The formation of the solar system can be dated quite accurately to 4,567,000,000 years ago, said Qing-Zhu Yin, assistant professor of geology at UC Davis and an author on the paper. Mars' metallic core formed a few million years after that. Previous estimates for how long the surface remained molten ranged from thousands of years to several hundred million years.

The persistence of a magma ocean on Mars for 100 million years is "surprisingly long," Yin said. It implies that at the time, Mars must have had a thick enough atmosphere to insulate the planet and slow down cooling, he said.

Vinciane Debraille, a postdoctoral researcher at the Lunar and Planetary Institute, Alan Brandon at the Johnson Space Center, Yin and UC Davis graduate student Benjamin Jacobsen inferred the early history of Mars in the distant past by studying meteorites that fell on Earth.

Meteorites called shergottites document volcanic activities in Mars between 470 million and 165 million years ago. These rocks were later thrown out of Mars' gravity field by asteroid impacts and delivered to Earth -- a free "sample return mission" accomplished by nature.

By precisely measuring the ratios of different isotopes of neodymium and samarium, the researchers could measure the age of the meteorites, and then use them to work out what the crust of Mars was like billions of years before that.

Planets form in three stages, Yin said. First, dust collects into objects tens of miles across. In the second phase, gravity pulls these planetisimals into bigger objects, roughly the size of Mars or the moon. Finally, these small planets collide to form three or four larger terrestrial planets, such as the Earth -- which is about 10 times the mass of Mars.

The giant collisions in this final phase would have released huge amounts of energy with nowhere to go except back into the new planet. The rock would have turned to molten magma and heavy metals sank to the core of the planet, releasing additional energy. The molten silicate mantle eventually cooled to form a solid crust on the surface of Mars.

Source: UC Davis Press Release

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Mars Doubles in Brightness


Nov. 21, 2007: During the past month, Mars has doubled in brightness and it is putting on a nice show for backyard stargazers.

linked-image

"Mars is starting to look really nice through my 10-inch telescope," reports amateur astronomer Friedrich Deters of LaGrange, North Carolina, who took the picture above on Nov. 17th.

"Very nice!" agrees Dan Peterson of Racine, Wisconsin, who captured a similar snapshot the next night.

The blue polar swirl in these pictures is the "North Polar Hood"—a giant icy cloud that forms over the Martian north pole during winter. Why blue? That's the color of sunlight scattered from very tiny crystals of ice (smaller than the wavelength of light itself) floating in the cloud. The blue hood vs. Mars' red terrain appear in pleasing contrast through any mid-sized backyard telescope.

You don't need a telescope to enjoy Mars, however. It is plainly visible to the naked eye, bright and red, standing out among the pale stars of Gemini as something definitely different.

Finding the constellation and the planet within is child's play on Nov. 26th and 27th. That's when the nearly full Moon glides past Mars, only one degree away, and draws attention to the pair. If you can find the full Moon, you can find Mars. Look east before bedtime on Monday evening, Nov. 26th, or west before dawn on Tuesday morning, Nov. 27th.

linked-image


Take a cup of coffee outside on Nov. 27th and spend some time sipping it while the sun rises and a hint of blue infuses the twilight sky. The sight of the silver Moon and red Mars backlit by blue sky is breathtaking. Sky maps: Nov. 26, Nov. 27.

Why has Mars gotten so bright and attractive? It's because Earth and Mars are converging. At closest approach on Dec. 18th, the two worlds will lie only 55 million miles apart. That may sound like a great distance, but it is just a hop, skip and a jump on the vast scale of the solar system. NASA is taking advantage of the close encounter to send a new mission to Mars: the Phoenix Lander. Phoenix launched in August 2007 and is due to reach Mars in May 2008, joining the Mars rovers Spirit and Opportunity already there.

Take a look at Mars: If it is this good now, what will it be like in December? Stay tuned!


Author: Dr. Tony Phillips | Editor: Dr. Tony Phillips | Credit: Science@NASA

____________________________________________

more information


Mars At Its Closest And Brightest Until 2016 This December -- from Jack Stargazer

Moon-Mars Sky Maps: Nov. 26, Nov. 27.

NASA's Future: The Vision for Space Exploration

Source: Science@NASA

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International Group Plans Strategy for Mars Sample Return Mission


The linked-image press release is reproduced below:

Dec. 10, 2007
Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown@nasa.gov


RELEASE: 07-269

International Group Plans Strategy for Mars Sample Return Mission


WASHINGTON - NASA and an international team are developing plans and seeking recommendations to launch the first Mars mission to bring soil samples back to Earth. The ability to study soil from Mars here on Earth will contribute significantly to answering questions about the possibility of life on the Red Planet. Returned samples also will increase understanding of the useful or harmful properties of Martian soil, which will support planning for the eventual human exploration of Mars.

A task force named the International Mars Architecture for Return of Samples, or IMARS, recently met in Washington to lay the foundation for an international collaboration to return samples from Mars. NASA hosted the meeting. IMARS meeting participants included representatives from more than half a dozen countries and NASA, the European Space Agency, or ESA, the Canadian Space Agency and the Japan Aerospace Exploration Agency.

IMARS is a committee of the International Mars Exploration Working Group, or IMEWG. The group was formed in 1993 to provide a forum for the international coordination of Mars exploration missions.

"The potential paradigm-changing science from Mars samples makes this mission a high priority of the National Academy of Sciences," said Doug McCuistion, NASA's Mars Exploration program director, Science Mission Directorate, Washington.

"The exciting progress being made by the IMARS team is contributing directly to making this mission a reality in the next decade, All spacefaring nations have a standing invitation from IMEWG to participate in IMARS."

Scientists reviewed past engineering work on a Mars sample return mission, international science priorities, and sample receiving facility requirements. The IMARS team made significant progress in many of the key issues associated with the integration of science and engineering challenges. The team established a common strategy for launching a Mars sample return mission and achieving scientific objectives that can be met only by returning Martian soil to Earth.

"For Europe this is a major step to shape the future of the ESA Aurora Exploration Programme in 2008," said Bruno Gardini, ESA's Exploration Program Manager. The Aurora Programme is part of Europe's strategy for space, initiated by ESA in 2001 to create and implement a long-term European plan for robotic and human exploration of the solar system.

The next steps in preparing for a Mars sample return mission includes more detailed international trade studies on engineering and mission specifics, greater detail on science and sample requirements, and definition and requirements for Earth-based facilities. IMARS will address the technical issues in upcoming meetings, along with preliminary discussions of the possible roles of interested nations and agencies.

For more information about NASA's Mars Program, visit:
_http://www.nasa.gov/mars

- end -

--------------------------------------------------------------------------------


Source: NASA Press Release 07-269

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NASA Study Reveals Less Water in Mars' Clouds


The NASA/Ames Research Center press release is reproduced below:

Dec. 6, 2007
John Bluck
NASA Ames Research Center, Moffett Field, Calif.
Phone: 650-604-5026
Email: John.G.Bluck@nasa.gov


RELEASE: 07_89AR


NASA Study Reveals Less Water in Mars' Clouds


MOFFETT FIELD, Calif. – Martian clouds may contain less water than previously thought, according to a new NASA study.

New NASA laboratory measurements of simulated martian clouds reveal that scientists may have been overestimating the amount of water in the planet's atmosphere.

"The martian clouds we are studying are composed of water ice, like some clouds on Earth. However, they are forming at very cold temperatures, often below minus 100 degrees Celsius (minus 148 degrees Fahrenheit)," said Tony Colaprete, a planetary scientist at NASA's Ames Research Center, Moffett Field, Calif. "What we have found in our laboratory studies is that it is much harder to initiate cloud formation at these cloud temperatures than what we thought," he explained.

"This difficulty results in larger cloud particles, which fall out of the atmosphere more quickly and, thus, result in less cloud mass and a drier atmosphere," Colaprete explained.

Colaprete will present his findings on at 1:40 p.m. PST Tuesday, Dec. 11, 2007, during the annual American Geophysical Union (AGU) fall meeting at San Francisco's Moscone Convention Center South in Exhibit Hall B.

Previously, scientists believed that martian clouds would form at 100 percent relative humidity, but the new study shows that martian air has to be more supersaturated with water to form clouds than scientists theorized before.

"We want to understand the climate of Mars and how the martian water cycle operates," Colaprete said. "Clouds are integral to this system, just as on Earth. However, assuming the clouds form or behave the same as on Earth, may be a bad assumption."

According to Colaprete, more accurate understanding of the processes that control martian clouds and water cycle are critical to understanding Mars' current and past climates.

A large water ice cap at the martian north pole dominates the martian water cycle. During the northern summer, this water ice cap evaporates, and winds carry the resulting water vapor to the south pole, according to Colaprete.

"The amount of water in the martian atmosphere varies greatly in space and time," Colaprete observed. Clouds in the atmosphere largely control the amount of water that comes off of the north pole and migrates to the south pole.

"Water that reaches the southern winter pole freezes to the surface," Colaprete said. "In the southern spring, this water re-evaporates and returns to the northern polar cap. The cycle is repeated year after year."

If all the water in the atmosphere were to freeze out to the surface, it would make a layer of ice about one-fifth the thickness of a human hair, according to Colaprete.

"Cloud mass is typically only 10 to 20 percent of the total water content. However, the thin martian atmosphere is much more sensitive/reactive to the influence of these clouds," he said.

- end -
--------------------------------------------------------------------------------


Source: NASA/ARC Press Release 07_89AR

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Mars: Closest Approach 2007


News Release Number: STScI-2007-45

linked-image


ABOUT THIS IMAGE:
NASA's Hubble Space Telescope took this close-up of the red planet Mars when it was just 55 million miles – 88 million kilometers – away. This color image was assembled from a series of exposures taken within 36 hours of the Mars closest approach with Hubble's Wide Field and Planetary Camera 2. Mars will be closest to Earth on December 18, at 11:45 p.m. Universal Time (6:45 p.m. EST).

Mars and Earth have a "close encounter" about every 26 months. These periodic encounters are due to the differences in the two planets' orbits. Earth goes around the Sun twice as fast as Mars, lapping the Red Planet about every two years. Both planets have elliptical orbits, so their close encounters are not always at the same distance. In its close encounter with Earth in 2003, for example, Mars was about 20 million miles closer than it is in the 2007 closest approach, resulting in a much larger image of Mars as viewed from Earth in 2003.

The two dominant dark swatches seen just south of the equator on this part of the planet are well observed regions that were originally labeled by early Mars observers. The large triangular shape to the right is Syrtis Major. The horizontal lane to the left is Sinus Meridani. One of NASA's Mars Exploration Rovers, named "Opportunity," landed at the western end of this region in January 2004. At the intersection of these two features is the prominent Huygens crater with a diameter of 270 miles (450 kilometers). South of Huygens is the Hellas impact basin, with a diameter of 1,100 miles (1,760 km) and a depth of nearly 5 miles (8 km). Hellas was formed billions of years ago when an asteroid collided into the Mars surface.

The planet appears free of any dust storms during this closest approach, however, there are significant clouds visible in both the northern and southern polar cap regions. The resolution is 13 miles (21 kilometers) per pixel.

For additional information, contact:

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4514
villard@stsci.edu

Keith Noll
Space Telescope Science Institute, Baltimore, Md.
410-338-1828
noll@stsci.edu

James Bell
Cornell University, Ithaca, NY 607-255-5911
jimbo@marswatch.tn.cornell.edu

Object Name: Mars

Image Type: Astronomical

Credit : NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (Cornell University), and M. Wolff (Space Science Institute, Boulder)

Source: HubbleSite - Newsdesk

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Mars: December 2007

News Release Number: STScI-2007-45

linked-image

ABOUT THIS IMAGE:

In December 2007, the Mars closest approach and opposition will occur within a week of each other. This is an exciting time for astronomers and planetary geologists to image and study our planetary neighbor. On December 18, Mars will be the closest it has been in the last two years, reaching a distance of 55 million miles from Earth. This series of images was taken with Hubble's Wide Field Planetary Camera 2 on December 1-7, within two weeks of its December 2007 closest approach. Each image shows the planet rotating about 90 degrees from the next image. This gives astronomers a full-globe look at the Red Planet.

[Top Left] - Mars on Dec. 1, 2007; longitude ~50 degrees

[Top Right] - Mars on Dec. 3, 2007; longitude ~225 degrees

[bottom Left] - Mars on Dec. 3, 2007; longitude ~320 degrees

[bottom Right] - Mars on Dec. 7, 2007; longitude ~140 degrees

Object Name: Mars

Image Type: Astronomical

Credit : NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (Cornell University), and M. Wolff (Space Science Institute, Boulder)

Source: HubbleSite - Newsdesk

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Mars Projection Map

News Release Number: STScI-2007-45

linked-image

ABOUT THIS IMAGE:

This map spans 360 degrees of Mars' surface, starting at a longitude line of 230 degrees on the left edge. It spans nearly to the north and south polar cap regions in Mars' latitude. This map is a composite of images taken with the Hubble Space Telescope's Wide Field Planetary Camera 2 in early December, just weeks before its December 18, 2007 closest approach.

Object Name: Mars

Image Type: Astronomical

Credit : NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (Cornell University), and M. Wolff (Space Science Institute, Boulder)

Source: HubbleSite - Newsdesk

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Mars Oppositions 1995-2007

News Release Number: STScI-2007-45

linked-image

ABOUT THIS IMAGE:

Every 26 months Mars is opposite the Sun in our nighttime sky. Since 1995, Mars has been at such an "opposition" with the Sun seven times. A color composite from each of the seven Hubble opposition observations has been assembled in this mosaic to showcase the beauty and splendor that is The Red Planet.

This mosaic of all seven globes of Mars shows relative variations in the apparent angular size of Mars over the years. Mars was the closest in 2003 when it came within 35 million miles (56 million kilometers) of Earth. The part of Mars that is tilted towards the Earth also shifts over time, resulting in the changing visibility of the polar caps. Clouds and dust storms, as well as the size of the ice caps, can change the appearance of Mars on time scales of days, weeks, and months. Other features of Mars, such as some of the large dark markings, have remained unchanged for centuries.

Object Name: Mars

Image Type: Astronomical

Credit : NASA, ESA, and Z. Levay (STScI)

Source: HubbleSite - Newsdesk

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Relative Positions and Sizes for 1995-2007 Mars Oppositions

News Release Number: STScI-2007-45

linked-image

ABOUT THIS IMAGE:

This illustration shows the relative positions of Earth and Mars at the last seven Martian oppositions from 1995 through 2007. Opposition occurs when the Sun and Mars are on exact opposite sides of Earth, resulting in a full-phase for Mars, similar to a full moon. The images of Mars show the planet's apparent relative size at each opposition, as viewed by the Earth-orbiting Hubble Space Telescope. Orbits of the inner planets are to scale.

Object Name: Mars

Image Type: Astronomical/Illustration

Credit : NASA, ESA, and Z. Levay (STScI)

Source: HubbleSite - Newsdesk

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Ground-based Image of Mars, December 2007

News Release Number: STScI-2007-45

linked-image

ABOUT THIS IMAGE:

Mars as seen in the night sky on December 8, 2007. Image was taken in southern Alberta, Canada (latitude of 51° N) by astrophotographer Alan Dyer. Mars, located in the constellation Gemini, is rising along the eastern horizon. Above it, portions of the winter Milky Way are visible, along with the constellation Orion at the far right. Mars appears ruddy red, while the Orion Nebula, located under the belt stars and along the sword of Orion appears pink. This image was taken with a Canon 16-35mm lens at f/2.8 and 16mm setting. ISO 800 for 90 second tracked exposure with Canon 20Da camera.

Object Name: Mars

Image Type: Astronomical/Photograph

Credit : NASA, ESA, and A. Dyer

Source: HubbleSite - Newsdesk

Edited by Waspie_Dwarf

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heard that mars have life form once but now its dies, someday will earth be like MARS??

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heard that mars have life form once but now its dies, someday will earth be like MARS??

It is believed that the conditions once existed for life, there was liquid water. Primitive life (bacteria, lichen and similar life forms) may have existed on Mars and may even still exist there even now, but there is no evidence to support this.

Edited by Waspie_Dwarf
corrected typo.

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It is believed that the conditions once existed for life, there was liquid water. Privative life (bacteria, lichen and similar life forms) may have existed on Mars and may even still exist there even now, but there is no evidence to support this.

Wow this is something I once asked about.... Interesting.... :blush:

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Wow this is something I once asked about.... Interesting.... :blush:

Indeed, but you tended not to ask in a direct way. Rather than ask directly about conditions for life you would instead use vague phrases like "Earthlike" without ever specifying exactly what you defined as "Earthlike".

The most important part of this is the bit that people like to ignore...

there is no evidence to support this.
Without any evidence talk of life on Mars is little short of guess work. The conditions for life to exist is hugely different from saying that life did exist.

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Waspie:

Checkmate.....yes I did beat around the bush....with reservation about mentioning that fact of past primative life.

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NASA Delays Mars Scout Mission to 2013


The linked-image press release is reproduced below:

Dec. 23, 2007
JGrey Hautaluoma
Headquarters, Washington
202-358-0668
grey.hautaluoma-1@nasa.gov


RELEASE: 07-283

NASA Delays Mars Scout Mission to 2013


WASHINGTON - NASA announced today that the next mission in the Mars Scout program, originally planned for launch in 2011, is now targeted for launch in 2013. The schedule slip is because of an organizational conflict of interest that was discovered in one of the mission proposal team's Phase A Concept Study. This was the shortest delay for the mission possible because opportunities to send spacecraft to Mars occur only once every 26 months.

NASA will fund current proposals to meet a new launch date in 2013. Revised proposals will be due in August 2008, and the evaluation and selection will take place in December 2008.

In November, NASA postponed the Scout mission's evaluation, selection, and announcement so the agency could resolve an organizational conflict of interest. The conflict of interest was discovered shortly after the concept study reports were received.

The extent of the conflict was severe enough that NASA determined its only recourse was to stop the evaluation and reconstitute the entire review panel that provides the technical and cost analyses for mission selections.

"The panel's independent expertise and evaluation are critical to maintaining a fair and competitive mission selection process," said Michael Meyer, lead scientist for NASA's Mars Exploration Program, NASA Headquarters, Washington. "This was a difficult decision, but necessary to preserve the integrity of the process, while ensuring we have adequate resources for the mission we ultimately select."

The delay in selection, resulting from reconstituting the entire review team and replanning the evaluation schedule, is approximately four months. Because of the delay, proposers would be left an unacceptable schedule, and schedule reserve, to meet a targeted launch date of 2011. Changing the launch date to the next Mars opportunity in 2013 reestablishes an acceptable and achievable schedule for the mission.

"We regret the delay, but NASA is taking this step to be proactive in preventing problems early on," said Mars Exploration Program Director Doug McCuistion, NASA Headquarters. "Because these are cost-capped missions, it is better to address the schedule risk now rather than put the winning proposer at a cost and schedule disadvantage from the start. Delaying the next Scout mission and allowing the mission teams to replan their proposed missions for 2013 reestablishes an acceptable schedule to meet a Mars launch date. It will also reduce the risk of cost overruns driven by the tight mission schedule that would have resulted if launch had remained in 2011."

In the first round of the Mars Scout 2006 competition, two missions for 2011 originally selected from 26 proposals for further evaluation in a concept study phase. The selected missions were the Mars Atmosphere and Volatile EvolutioN mission, or MAVEN and the The Great Escape, or TGE, mission. The principal investigator for MAVEN is Bruce Jakosky, University of Colorado, Boulder. The TGE principal investigator is Jim Burch, Southwest Research Institute, San Antonio. Both missions would provide similar measurements of Mars' upper atmosphere, including its dynamics and evolution, which have been given a high priority by the scientific community.

The Mars Scout Program is designed to send a series of small, low-cost missions to the Red Planet that are competitively selected. The first robotic spacecraft in this program is the Phoenix lander, which was launched Aug. 4, 2007, and is scheduled to land in the icy northern polar region of Mars on May 25, 2008.

NASA's Mars Exploration Program seeks to characterize and understand Mars as a dynamic system, including its present and past environment, climate cycles, geology and biological potential. The Mars Exploration Program Office is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for the Mars Exploration Program, Science Mission Directorate, Washington.

For more information, visit:
_http://www.nasa.gov/mars

- end -

--------------------------------------------------------------------------------


Source: NASA Press Release 07-283

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Astronomers Monitor Asteroid to Pass Near Mars

12.21.07


WASHINGTON - Astronomers funded by NASA are monitoring the trajectory of an asteroid estimated to be 50 meters (164 feet) wide that is expected to cross Mars' orbital path early next year. Observations provided by the astronomers and analyzed by NASA's Near-Earth Object Office at the Jet Propulsion Laboratory in Pasadena, Calif., indicate the object may pass within 30,000 miles of Mars at about 6 a.m. EST (3 a.m. PST) on Jan. 30, 2008.


linked-image
This artist rendering uses an arrow to show the
predicted path of the asteroid on Jan. 30, 2008,
and the orange swath indicates the area it is
expected to pass through. Mars may or may
not be in its path.
Image credit: NASA/JPL
› Larger view (485Kb)
› Podcast: Is an Asteroid Heading Toward Mars?


"Right now asteroid 2007 WD5 is about half-way between Earth and Mars and closing the distance at a speed of about 27,900 miles per hour," said Don Yeomans, manager of the Near Earth Object Office at JPL. "Over the next five weeks, we hope to gather more information from observatories so we can further refine the asteroid's trajectory."

NASA detects and tracks asteroids and comets passing close to Earth. The Near Earth Object Observation Program, commonly called "Spaceguard," plots the orbits of these objects to determine if any could be potentially hazardous to our planet.

Asteroid 2007 WD5 was first discovered on Nov. 20, 2007, by the NASA-funded Catalina Sky Survey and put on a "watch list" because its orbit passes near Earth. Further observations from both the NASA-funded Spacewatch at Kitt Peak, Ariz., and the Magdalena Ridge Observatory in New Mexico gave scientists enough data to determine that the asteroid was not a danger to Earth, but could potentially impact Mars. This makes it a member of an interesting class of small objects that are both near Earth objects and "Mars crossers."

linked-image
Animation showing the possible paths of asteroid
2007 WD5. On January 30, 2008, the asteroid may
pass through any point seen in the dotted area.
Image credit: NASA/JPL
› See animation
› Larger view


Because of current uncertainties about the asteroid's exact orbit, there is a 1-in-75 chance of 2007 WD5 impacting Mars. If this unlikely event were to occur, it would be somewhere within a broad swath across the planet north of where the Opportunity rover is located.

"We estimate such impacts occur on Mars every thousand years or so," said Steve Chesley, a scientist at JPL. "If 2007 WD5 were to thump Mars on Jan. 30, we calculate it would hit at about 30,000 miles per hour and might create a crater more than half-a-mile wide." The Mars Rover Opportunity is exploring a crater approximately this size right now.

Such a collision could release about three megatons of energy. Scientists believe an event of comparable magnitude occurred here on Earth in 1908 in Tunguska, Siberia, but no crater was created. The object was disintegrated by Earth's thicker atmosphere before it hit the ground, although the air blast devastated a large area of unpopulated forest.

NASA and its partners will continue to track asteroid 2007 WD5 and will provide an update in January when further information is available. For more information on the Near Earth Object program, visit: _http://neo.jpl.nasa.gov/ .

linked-image
The current position of asteroid 2007
WD5, with its orbit shown in blue. The asteroid's
orbit stretches from just outside the Earth's orbit
at its closest point to the Sun, to the outer reaches
of the asteroid belt at its farthest.
Image credit: NASA/JPL
› Larger view


An audio interview/podcast regarding 2007 WD5 is available at: _http://www.nasa.gov/multimedia/podcasting/jpl-mars-20071220.html

A videofile related to this story is available on NASA TV and the Web. For information and schedules, visit: _http://www.nasa.gov/ntv.


Media contacts: DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov

Grey Hautaluoma 202-358-0668
NASA Headquarters, Washington
grey.hautaluoma-1@nasa.gov

2007-152


Source: NASA - Missions - Mars Edited by Waspie_Dwarf

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Catalina Sky Survey Discovers Space Rock That Could Hit Mars

The UA-based HiRISE team would have a ringside seat


The University of Arizona press release is reproduced below:

By Lori Stiles, University Communications
December 21, 2007

An asteroid discovered by The University of Arizona's Catalina Sky Survey has a one-in-75 chance of hitting Mars on Jan. 30, scientists say.

linked-image
The "eye" of the 60-inch telescope used in the Catalina Sky
Survey on Mount Lemmon.
(Lori Stiles)


Catalina Sky Survey team member Andrea Boattini discovered the asteroid, designated 2007 WD5, with the UA's Mount Lemmon 60-inch telescope in the Santa Catalina Mountains north of Tucson on Nov. 20.

At the time, the asteroid was at 20th magnitude brightness, which is about 400,000 times fainter than the faintest object most people can see with their naked eye on a dark night, survey team member Ed Beshore said. The asteroid is now 16 times dimmer than it was when it was discovered, he added.

Astronomers monitoring the trajectory of the asteroid estimate that it is 164-feet wide. Observations provided by the astronomers and analyzed by NASA's Near-Earth Object Office at the Jet Propulsion Laboratory in Pasadena, Calif., indicate the object may pass within 30,000 miles of Mars at about 6 a.m. EST on Jan. 30.

linked-image
The Catalina Sky Survey opens the 60-inch
Mount Lemmon telescope for another nightly
search for near-Earth objects.
(Lori Stiles)


The Mars-approaching asteroid is about the size of the object that blasted out Meteor Crater, in northern Arizona, about 50,000 years ago. The object that created Meteor Crater is believed to be a metallic asteroid – more like a ball bearing that a rock, Beshore said. The newly found Mars-approaching asteroid is probably a stony asteroid, as are most asteroids, Beshore said.

Scientists calculate it is traveling at 8 miles a second, or 15 times faster than a rifle bullet, Beshore added.

Asteroid 2007 WD5 also is being compared to the object that exploded over Tunguska, Siberia, with the energy of a 3-megaton bomb in 1908. The Tunguska object is believed to be a cometary fragment, Beshore said.

In the unlikely event that 2007 WD5 does hit Mars, it would hit somewhere within a broad swath across the planet north of where the Opportunity rover is, according to NASA.

"We estimate such impacts occur on Mars every thousand years or so," Steve Chesley, an astronomer with the Near Earth Object Program at NASA's Jet Propulsion Laboratory, said in a NASA news release. "If 2007 WD5 were to thump Mars on Jan. 30, we calculate it would hit at about 30,000 miles per hour and might create a crater more than a half-a-mile wide."

The Mars Reconnaissance Orbiter, which is mapping the planet, would have a front-row seat, Chesley added.

The orbiter's science payload includes the High Resolution Imaging Experiment, or HiRISE, which operates the most powerful camera ever to orbit another planet.

"If the asteroid hits Mars we'll get a great look at the crater within a few days of impact," said HiRISE principal investigator Alfred S. McEwen of the UA's Lunar and Planetary Laboratory.

HiRISE images of recent Martian impact craters can be found on the HiRISE Web site.

The Catalina Sky Survey this year broke all records for discoveries of near-Earth objects, or NEOs. The survey found 450 NEOs in 2007. The actual number likely will be a bit higher when the final 2007 count is in, Beshore said. That tops its record 400 NEO discoveries in 2006 and 310 NEO discoveries in 2005.

The team's rising rate of NEO discoveries reflects that the survey continues to improve its technique and technologies, said the Lunar and Planetary Laboratory's Steve Larson, Catalina Sky Survey director.

The Catalina Sky Survey, known as the CSS, is conducted in the Northern Hemisphere by the Mount Lemmon Survey north of Tucson, and in the Southern Hemisphere by the Siding Spring Survey near Coonabarabran, New South Wales, Australia.

CSS is one of four surveys funded by NASA to carry out a U.S. congressional mandate to find and catalog at least 90 percent of all near-Earth objects larger than 1 kilometer across (six-tenths mile) by the end of 2008.

The impact of a kilometer-diameter asteroid would have global consequences to civilization as we know it, Larson said. If an object even a third as large hit Earth, it would explode with 24 times the energy of the world's largest thermonuclear bomb explosion: a 58-megaton Soviet bomb exploded in 1961.

The technology to detect and track these objects has been available for only a decade, and although impacts of these large NEOs are rare, this is the first time that any potential danger can be quantified as the first step in possibly mitigating a disaster, Larson said.

Source: UA Press Release

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MIT, Harvard offer solution to Mars enigma

How Mars could have been warm and wet but limestone-free



The Massachusetts Institute of Technology press release is reproduced below:

David Chandler, MIT News Office
December 27, 2007


Planetary scientists have puzzled for years over an apparent contradiction on Mars. Abundant evidence points to an early warm, wet climate on the red planet, but there's no sign of the widespread carbonate rocks, such as limestone, that should have formed in such a climate.

Now, a detailed analysis in the Dec. 21 issue of Science by MIT's Maria T. Zuber and Itay Halevy and Daniel P. Schrag of Harvard University provides a possible answer to the mystery. In addition to being warmed by a greenhouse effect caused by carbon dioxide in the atmosphere, as on Earth, the early Mars may have had the greenhouse gas sulfur dioxide in its atmosphere. That would have interfered with the formation of carbonates, explaining their absence today.

linked-image
Image / NASA/JPL/Cornell
Taken by the panoramic camera
on the Mars Exploration Rover
Opportunity, image shows a close
up of the rock dubbed 'El Capitan.'
The iron-bearing mineral jarosite,
which was found in the rock, led
MIT and Harvard researchers to
posit that early Mars may have
had the greenhouse gas sulfur
dioxide in its atmosphere.

Enlarge image


It would also explain the discovery by the twin Mars rovers, Spirit and Opportunity, of sulfur-rich minerals that apparently formed in bodies of water in that early Martian environment. And it may provide clues about the Earth's history as well.

The challenge was to interpret the planet's history, based on the data gathered by the Mars rovers--and especially Opportunity's discovery of sulfate minerals--from just tiny fractions of the surface, says Zuber, who is head of MIT's Department of Earth, Atmospheric and Planetary Sciences and the E.A. Griswold Professor of Geophysics. "How do you take very detailed measurements of chemical composition at one tiny place on Mars," she says, "and put it into the context of the broad evolution of the planet?" The breakthrough, she said, was when she and her colleagues realized "we'd been after the wrong molecule."

After several years of exploring the role of carbon dioxide and the carbon cycle, she said, they realized "maybe the key is sulfur dioxide, not carbon dioxide."

It was Opportunity's discovery of the mineral jarosite, which only forms in highly acidic water, that set them thinking about how that acidic environment could have come about. Sulfur provided the answer.

The new analysis suggests that on Mars, sulfur went through a whole cycle through the atmosphere, bodies of water on the surface, and burial in the soil and crust, comparable to the well-known carbon cycle on Earth. Through most of Earth's history, carbon dioxide has been released in volcanic eruptions, then absorbed into seawater, where it fosters the formation of calcium carbonate (limestone), which gets buried in ocean sediments.

Much evidence suggests Mars may once have had an ocean that covered about a third of the planet, in its northern hemisphere. Sulfur dioxide dissolves easily in water, so after being spewed into the atmosphere by the giant volcanoes of Mars' Tharsis bulge, much of it would have ended up in the water, where it inhibited the formation of carbonate minerals but led to the formation of silicates and sulfites, such as calcium sulfite.

These minerals degrade relatively rapidly, so they would not be expected on the surface of Mars today. But they also allow formation of clays, which have been found on Mars, and which added to the puzzle since clays are usually associated with the same conditions that produce carbonates.

The new picture of a sulfur cycle helps to solve another mystery, which is how early Mars could have been warm enough to sustain liquid water on its surface. A carbon dioxide atmosphere produces some greenhouse warming, but sulfur dioxide is a much more powerful greenhouse gas. Just 10 parts per million of sulfur dioxide in the mostly carbon dioxide air would double the amount of warming and make it easier for liquid water to be stable.

The analysis may also tell us something about our own planet's past. The early Earth's environment could well have been similar to that on Mars, but most traces of that era have been erased by Earth's very dynamic climate and tectonics. "This might have been a phase that Earth went through" in its early years, Zuber says. "It's fascinating to think about whether this process may have played a role" in the evolution of the early Earth.

The work was funded by NASA, a Radcliffe fellowship, the George Merck Fund and a Harvard graduate fellowship.

Source: MIT Press Release Edited by Waspie_Dwarf

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Mars Impact Probability Increases to 4 Percent


Don Yeomans, Paul Chodas and Steve Chesley
NASA/JPL Near-Earth Object Program Office
December 28, 2007

The impact probability for a collision of asteroid 2007 WD5 with Mars on January 30 has increased from 1.3% to 3.9%.

Pre-discovery observations of asteroid 2007 WD5, taken on November 8, 2007 have allowed its orbit to be refined and the uncertainties for the late January Mars encounter have been improved. The impact probability resulting from the recent orbit refinement has increased to a surprising 3.9% (about 1 in 25 odds). The uncertainty region during the Mars encounter now extends over 400,000 km along a very narrow ellipsoid that is only 600 km wide. Since the uncertainty region intersects Mars itself, a Mars impact is still possible. However, the most likely scenario is that additional observations of the asteroid will allow the uncertainty region to shrink so that a Mars impact is ruled out. In the unlikely event of an impact, the time would be 2008 January 30 at 10:56 UT (2:56 a.m. PST) with an uncertainty of a few minutes.

linked-image
The current position of asteroid 2007 WD5, with its orbit shown
in blue. The asteroid's orbit stretches from just outside the Earth's
orbit at its closest point to the Sun, to the outer reaches of the
asteroid belt at its farthest.


linked-image
Updated Uncertainty Region for 2007 WD5 at encounter with
Mars, shown as white dots. The thin white line is the orbit of Mars.
The blue line traces the motion of the center of the uncertainty
region, which is the most likely position of the asteroid.


The pre-discovery observations were located by Andy Puckett, a recent Ph.D. from the University of Chicago who has since moved to the University of Alaska Anchorage. Dr. Puckett located the observations in the archive of the Sloan Digital Sky Survey II, which contains extensive repeat coverage of 300 square degrees along the sky's celestial equator. The observations were taken using a 2.5 meter aperture telescope at the Apache Point Observatory near Cloudcroft, New Mexico. For the recent orbit refinement, these pre-discovery observations on November 8 were added to the existing observations provided by the Catalina Sky Survey and Spacewatch observatories (both near Tucson AZ) as well as New Mexico Tech's Magdalena Ridge Observatory.


Related:


Source:NASA - NEO Program

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New Observations Slightly Decrease Mars Impact Probability


Don Yeomans, Paul Chodas and Steve Chesley
NASA/JPL Near-Earth Object Program Office
January 2, 2008

Additional position observations for asteroid 2007 WD5 taken on December 29 through January 2 have been used to improve the accuracy of the asteroid's orbit. As a result, the range of possible paths past Mars has narrowed by a factor of 3 and the most likely path has moved a little farther away from the planet, causing the Mars impact probability to decrease slightly to 3.6% (about one chance in 28). The new positional observations were made using the 2.4 meter telescope at New Mexico Tech's Magdalena Ridge Observatory and reported by astronomer Bill Ryan. It seems likely that as additional observations further shrink the uncertainty region of this asteroid, the region will no longer intersect Mars and the impact probability will quickly drop to zero.

linked-image
Updated Uncertainty Region for 2007 WD5 at encounter with Mars, shown as white dots. The thin white line is the orbit of Mars. The blue line traces the motion of the center of the uncertainty region, which is the most likely position of the asteroid. Note that the scale is considerably finer than it has been in past diagrams


Related:


Source:NASA - NEO Program

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Mars Impact Seems Less Likely


Steve Chesley, Paul Chodas and Don Yeomans
NASA/JPL Near-Earth Object Program Office
January 8, 2008

We have updated the orbit of 2007 WD5 using new observations from the 3.5-meter telescope at the Calar Alto Observatory in Spain. This update also incorporates refinements to the Sloan precovery observations mentioned previously. While the best estimate of close approach distance remains steady at about 30,000 km, the uncertainty in position at the close approach has decreased by a factor of three. As a result, the impact probability estimate has fallen to 2.5%, or 1-in-40 odds. If the estimated miss distance remains stable in future updates, the impact probability will continue to fall as continuing observations further constrain the uncertainties.

linked-image
Updated Uncertainty Region for 2007 WD5 at encounter with Mars, shown as white dots. The thin white line is the orbit of Mars. The blue line traces the motion of the center of the uncertainty region, which is the most likely position of the asteroid.


Related:


Source:NASA - NEO Program

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2007 WD5 Mars Collision Effectively Ruled Out - Impact Odds now 1 in 10,000


Steve Chesley, Paul Chodas and Don Yeomans
NASA/JPL Near-Earth Object Program Office
January 9, 2008

Since our last update, we have received numerous tracking measurements of asteroid 2007 WD5 from four different observatories. These new data have led to a significant reduction in the position uncertainties during the asteroid's close approach to Mars on Jan. 30, 2008. As a result, the impact probability has dropped dramatically, to approximately 0.01% or 1 in 10,000 odds, effectively ruling out the possible collision with Mars.

Our best estimate now is that 2007 WD5 will pass about 26,000 km from the planet's center (about 7 Mars radii from the surface) at around 12:00 UTC (4:00 am PST) on Jan. 30th. With 99.7% confidence, the pass should be no closer than 4000 km from the surface.

linked-image
Updated Uncertainty Region for 2007 WD5 at encounter with Mars, shown as white dots. The thin white line is the orbit of Mars. The blue line traces the motion of the center of the uncertainty region, which is the most likely position of the asteroid.

linked-image
Image of 2007 WD5 from the University of Hawaii 2.2-meter telescope on Mauna Kea, Hawaii. The circled dot is the asteroid. Other dots are artifacts from cosmic rays. The stars are trailed because the telescope is tracking the asteroid as it moves among the stars. (Credit: Tholen, Bernardi, Micheli with support from the National Science Foundation).

The sequence of updates over the last few weeks has been typical of past potential impact scenarios, with the odds of impact initially surging and later plummeting towards zero. Early on, the uncertainty region is very large and the probability of impact is rather low. As the uncertainty narrows, but still includes the planet, the probability initially increases. But eventually, as in this case, the uncertainty region shrinks to the point that it no longer overlaps the planet, and the probability of impact begins a precipitous decline. This rise and fall of the computed hazard was most notably seen in Dec. 2004 when asteroid 99942 Apophis briefly reached a 2.7% chance of impact with Earth in April 2029. In every case, the height and the timing of the peak probability - and the subsequent decline - cannot be known until the uncertainty region has shrunk to the point where it no longer intersects the planet.

NASA's Spaceguard Survey continues searching for Near-Earth Asteroids such as 2007 WD5, endeavoring to discover 90% of those larger than 1 km in size, a goal that should be met within the next few years. Each discovered asteroid is continually monitored for the possibility of impact. For 2007 WD5, these analyses show there is no possibility of impact with either Mars or Earth in the next century.

This unfolding story and the present results have been made possible by the tracking efforts of many astronomers at several observatories around the world:

  • 2007 WD5 was discovered using the Mt. Lemmon 1.5-meter telescope by Andrea Boattini of the University of Arizona's Catalina Sky Survey, which is led by Steve Larson.
  • Follow-up from archival images taken by the 1.8-meter telescope on Kitt Peak in Arizona were provided by Terrence H. Brezzi of the University of Arizona's Spacewatch Project, which is led by Robert McMillan.
  • Andy Puckett of the Univ. of Alaska obtained pre-discovery measurements from archival images of the Sloan Digital Sky Survey’s 2.5-meter telescope on Apache Point, NM.
  • Bill Ryan of New Mexico Tech's Magdalena Ridge Observatory observed 2007 WD5 on several crucial nights, with critical support from university and observatory staff.
  • Observations from the 6.5-meter Multi-Mirror Telescope (MMT) Observatory in Arizona were provided by a team consisting of Holger Israel (Univ. Bonn), Matt Holman (Harvard/CfA), Steve Larson (Univ. Ariz.), Faith Vilas (MMTO), Cesar Fuentes (Harvard/CfA), David Trilling (Univ. Ariz.) and Maureen Conroy (Harvard/CfA).
  • The 3.5-meter telescope at the Calar Alto Observatory in Spain provided follow-up through a team consisting of Adriano Campo Bagatin (Univ. Alicante), Gilles Bergond (Calar Alto Obs.), Rene Duffard (Inst. de Astrofisica de Andalucia), Jose Luis Ortiz (Inst. de Astrofisica de Andalucia), Reiner Stoss (Obs. Astronomico de Mallorca and Astronomisches Rechen-Institut) and Javier Licandro (Inst. de Astrofisica de Canarias).
  • Fabrizio Bernardi, Marco Micheli and Dave Tholen of the Univ. of Hawaii Institute for Astronomy observed the asteroid at its faintest using the 2.2-meter UH telescope on Mauna Kea in Hawaii.


Related:


Source:NASA - NEO Program

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