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Dawn Begins Approach to Dwarf Planet Ceres


Waspie_Dwarf

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Dawn Spacecraft Begins Approach to Dwarf Planet Ceres

• Dawn has entered its approach phase toward Ceres

• The spacecraft will arrive at Ceres on March 6, 2015

NASA's Dawn spacecraft has entered an approach phase in which it will continue to close in on Ceres, a Texas-sized dwarf planet never before visited by a spacecraft. Dawn launched in 2007 and is scheduled to enter Ceres orbit in March 2015.

Dawn recently emerged from solar conjunction, in which the spacecraft is on the opposite side of the sun, limiting communication with antennas on Earth. Now that Dawn can reliably communicate with Earth again, mission controllers have programmed the maneuvers necessary for the next stage of the rendezvous, which they label the Ceres approach phase. Dawn is currently 400,000 miles (640,000 kilometers) from Ceres, approaching it at around 450 miles per hour (725 kilometers per hour).

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Crazy Engineering: Ion Propulsion for the Dawn Mission

Ion propulsion isn’t something found only in science fiction. JPL engineer Mike Meacham looks at how ion engines are being used to drive NASA's Dawn spacecraft through the solar system. Dawn is approaching dwarf planet Ceres in the main asteroid belt with arrival expected in March 2015. Previously, Dawn orbited Vesta, the second-largest body in the asteroid belt. Learn how ion propulsion works and why it's the reason Dawn will be the first spacecraft ever to orbit two solar system bodies.

More about Dawn at: http://dawn.jpl.nasa.gov/

Credit: JPL/NASA

Source: NASA/JPL - Videos

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I had forgotten aboutthis little probe. It's amazing how many missions NASA/JPL currently have under way and/or are preparing to launch in the next 5-8 years.

Edited by Merc14
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Interesting, though I think it would be a bigger step tackling some more stellar endeavors as a permanent moon base than little missions here and there.

S

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Interesting, though I think it would be a bigger step tackling some more stellar endeavors as a permanent moon base than little missions here and there.

S

Little missions? Come on, this is the first man made spacecraft to orbit two different solar objects. Anyways, what is a moon base as compared to the scientific discoveries these so called little missions have made in the last three decades.
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Interesting, though I think it would be a bigger step tackling some more stellar endeavors as a permanent moon base than little missions here and there.

S

Be patient; baby steps and all that. A permanent moon base would be expensive to say the least, probably at this point not cost effective in terms of scientific knowledge to be gotten. People in space is much more difficult than machines.
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  • 3 weeks later...

Dawn is beginning to get an interesting view of the dwarf planet Ceres. It appears to have photographed a tiny spot on this little world, which is very much brighter than its surroundings. The Hubble Space Telescope may have photographed this same spot, or one somewhat similar to it, a number of years ago. In the Dawn image, this spot appears quite a bit brighter than that seen by Hubble.

Dawn's images will soon surpass in clarity those of Hubble, as it approaches Ceres. Before too long perhaps we will have a better idea of what this bright spot amounts to. Perhaps it's an icy peak, or a sizable field of ice on the surface.

This explanation seems doubtful, though, since ice on the surface of Ceres is considered to be unstable. Link to article, plus the relevant Dawn and Hubble images. below:

http://www.universet...w-of-ceres-yet/

Edited by bison
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The Wikipedia article confirms that the bright spot on Ceres, imaged by both Hubble and Dawn, is at the same location on the planet. This probably rules out a transient feature, such as temporary ice vented from the interior of Ceres, which soon sublimed away.

Ceres is on its own. It is not in orbit of a large, nearby planet, which might cause interior heat through tidal flexing. Ice volcanism from consistent sites, as on Neptune's moon Triton, does not appear likely.

http://en.wikipedia.org/wiki/Ceres_(dwarf_planet)

Edited by bison
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Dawn Delivers New View of Ceres

The Dawn spacecraft observed Ceres for an hour on Jan. 13, 2015, from a distance of 238,000 miles (383,000 kilometres). A little more than half of its surface was observed at a resolution of 27 pixels. This video shows bright and dark features.

This video was created from an animated gif and has been looped five times.

For the full story see here: http://www.jpl.nasa.gov/news/news.php?release=2015-023

Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

Source: NASA/JPL

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Wanted to get some idea of the size of the bright patch on Ceres. This dwarf planet is known to be 590 miles in diameter. Measuring the width of its image and that of the bright spot seems to show that the latter is some 30 miles across. That's quite an accumulation of ice on a world where any ice on the surface is supposed to be subliming away whenever the Sun is on it.

For my part, this bright spot appears to be a genuine unknown that does not admit of a satisfactory explanation, as yet. New and better images from Dawn are expected by the end of the month.

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NASA’s Dawn Spacecraft Captures Best Ever View of Dwarf Planet Ceres

This animation of the dwarf planet Ceres was made by combining images taken by NASA's Dawn spacecraft on Jan. 25. The spacecraft's framing camera took these images, at a distance of about 147,000 miles (237,000 kilometers) from Ceres, and they represent the highest-resolution views to date of the dwarf planet.

This video was created from an animated gif and has been looped five times.

Credit: NASA/JPL

Source: NASA

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That's quite an accumulation of ice on a world where any ice on the surface is supposed to be subliming away whenever the Sun is on it.

This is nonsense.

Ceres has a rocky core covered by a 100 Km thick mantle of ice. Why are you surprised that a surface made of ice might have ice on it?

As for subliming away... you really are exagerating that.

Yes, ice in direct sunlight will sublime, forming a tenuous atmosphere but that doesn't mean surface features are going to vanish in short periods of time.

There are localised regions of Ceres where Ceres gives of 3Kg of water per second, but to put that in perspective Ceres has a mass of 9.43 ±; 0.07 x 1020 Kg.

At 3kg per second Ceres would lose less than 0.00001% of it's mass in a million years.

The white area is likely to have a mundane explanation. If Ceres has a "dirty" surface then it is quite possible that this is pristine, subsurface, ice that has been exposed by some geological process, the outgassing of water or as the result of a fresh impact crater. Either way we will know in a few weeks.

Edited by Waspie_Dwarf
lots of typos.
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A mundane explanation? Wouldn't that be a cerean explanation, or is that cereal?

The ESA's Herschel Space Telescope looked at the spectrum of Ceres. It found no evidence of ice, but did detect a couple of plumes of water vapor. If it was sensitive enough to detect the latter, perhaps it would have been able to detect a 30 mile-wide field of ice, as well.

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The next Ceres imaging session by the Dawn mission is planned for Tuesday, Feb. 3rd, just four days from today. Images of Ceres 70 pixels in width will be obtained, giving a resolution figure of about 8.5 miles per pixel.

This is ~ 63 percent better resolution than its current best images, and better than twice the resolution of the Hubble Space Telescope images, which for many years stood as the best available images of Ceres. At that time, Dawn will still be about 91,000 miles from Ceres.

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The new images of Ceres are out. Several craters can been seen, particularly in the South polar area. The bright spot, in the North, which has been getting so much attention, appears, upon measurement, to be roughly 35 miles across. There now appears to be a much brighter, and much smaller spot within it. See linked article, below for animated image sequence, and further details.

http://astronomynow....views-of-ceres/

Edited by bison
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The new images of Ceres are out. Several craters can been seen, particularly in the South polar area. The bright spot, in the North, which has been getting so much attention, still appears, upon measurement, to be roughly 40 miles across. There now appears to be a much brighter, and much smaller spot within it. See linked article, below for animated image sequence, and further details.

http://astronomynow....views-of-ceres/

That bright spot looks as if it may have some elevation but hard to tell.

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Its still probably too soon to be certain about elevation. The only definite signs of relief are the craters, in the South. The bright spot doesn't really look like any of these.

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Its still probably too soon to be certain about elevation. The only definite signs of relief are the craters, in the South. The bright spot doesn't really look like any of these.

In a month we'll know a lot more as she is due to enter orbit March 6th.

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Dawn Gets Closer Views of Ceres

This animation showcases a series of images NASA's Dawn spacecraft took on approach to Ceres on Feb. 4, 2015 at a distance of about 90,000 miles (145,000 kilometers) from the dwarf planet.

This video was created from an animated gif and has been looped five times.

Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

Source: NASA

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In a month we'll know a lot more as she is due to enter orbit March 6th.

Even before that, though, we'll see images with 1.7 times better resolution than today, taken on Feb. 12, and 3.2 times better, from Feb. 19th.

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An interesting article on the latest images from Ceres, and possible interpretations of them, with discussion after. Several 'stills' from the new, animated series of images.

The author of the article, Bob King, at Universe Today, thinks the white spot looks like a depression, possibly even a crater. Others think they see a rise in the terrain. He also notes several other less conspicuous 'bright spots'.

One interesting point was brought out-- That the images have had their contrast 'stretched' The darkest apparent shade is assigned black, the lightest shade white. All of Ceres is actually quite dark. Even the 'bright spot' has an albedo of only 50-- giving it about the color of asphalt, which does not immediately suggest the presence of ice. Link to article and discussion, below:

http://www.universet...hite-spots-now/

Edited by bison
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An interesting article on the latest images from Ceres, and possible interpretations of them, with discussion after. Several 'stills' from the new, animated series of images.

The author of the article, Bob King, at Universe Today, thinks the white spot looks like a depression, possibly even a crater. Others think they see a rise in the terrain. He also notes several other less conspicuous 'bright spots'.

One interesting point was brought out-- That the images have had their contrast 'stretched' The darkest apparent shade is assigned black, the lightest shade white. All of Ceres is actually quite dark. Even the 'bright spot' has an albedo of only 50-- giving it about the color of asphalt, which does not immediately suggest the presence of ice. Link to article and discussion, below:

http://www.universet...hite-spots-now/

It does look like a depression now although, as with my earlier suggestion that it was elevated, very hard to tell at this point. The author notices the seeming rise to a peak just as the spot disappears in the bottom animation but the new image says depression. I'm glad we'll be getting an answer soon, which is more than I can say about your mysterious driveway. :yes:

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Just to give some perspective to the albedo situation at Ceres--- The overall albedo is about 9%, that of the 'bright spot' about 50%. The 'bright spot' is approximately 5 & 1/2 times brighter than the disk of Ceres, taken as a whole.

By comparison, the Moon, also a comparatively dark body, has an averaged albedo of 12%. Its brightest point is the crater Aristarchus, which has an albedo of 18%, or only 1 & 1/2 times the average.

So we see that the 'bright spot' on Ceres is much brighter with respect to its surroundings, that the brightest point on the Moon is.

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