Scientists are planning to contact aliens

[+Hammerclaw]

2 hours ago, lost_shaman said:

Ok.  That is quite obvious.

Glad Mass Media do NOT design Spaceships! I agree!

What is a "Human Timescale"? 

A human lifetime, or fraction thereof. That's why the Warp or FTL drives are ubiquitous gimmicks in science fiction. They reduce the universe to human proportions so man can gad about the Galaxy as he would Earth's oceans.

[lost_shaman]

The reason I asked you, because Time is Relative it is not constant so I was curious as to how you would define a "Human Timescale". If a Starship was traversing the Stars at Relativistic speeds then because of Time Dilation a "Human Timescale" could mean anything and must be further defined in order to have any meaning.

Of course with current technology a "Human Timescale" would be Mars. 

[Sakari]

This is how we found Chukar when hunting. They would call out. Otherwise we would not know they were there...

Know what happened next?

[+Hammerclaw]

6 hours ago, lost_shaman said:

The reason I asked you, because Time is Relative it is not constant so I was curious as to how you would define a "Human Timescale". If a Starship was traversing the Stars at Relativistic speeds then because of Time Dilation a "Human Timescale" could mean anything and must be further defined in order to have any meaning.

Of course with current technology a "Human Timescale" would be Mars. 

There is no such means to circumvent natural law--for humans, at least--at this point in time. So, that's all hypothetical. Without any science fiction gimmicks man is limited by his lifespan. A voyage to the stars will require generation ships and the immense resources to sustain them on the journey.

[psyche101]

13 hours ago, Hammerclaw said:

There is no such means to circumvent natural law--for humans, at least--at this point in time. So, that's all hypothetical. Without any science fiction gimmicks man is limited by his lifespan. A voyage to the stars will require generation ships and the immense resources to sustain them on the journey.

He is talking about Time Dilation. Makes it theoretically possible for us to travel to the centre of the galaxy in one life span, in fact I have seen theory that brings the trip down to 12 years, LS may have that link as he has provided it before, just the people on earth would have to wait through conventional time to hear about the trip. No difference to them. 

[lost_shaman]

13 hours ago, Hammerclaw said:

There is no such means to circumvent natural law--for humans, at least--at this point in time. So, that's all hypothetical. Without any science fiction gimmicks man is limited by his lifespan. A voyage to the stars will require generation ships and the immense resources to sustain them on the journey.

Well at this point and time we can't put a man on the Moon or send a crew to Mars either. Of course we will likely achieve both in the next 10-15 years. But back to the point, what if the EM Drive works, it certainly seems to, then that or something similar will open up the possibility of Relativistic speeds in the very near future. So we may be steadily moving to a point where this is not "hypothetical".

[+Hammerclaw]

2 hours ago, lost_shaman said:

Well at this point and time we can't put a man on the Moon or send a crew to Mars either. Of course we will likely achieve both in the next 10-15 years. But back to the point, what if the EM Drive works, it certainly seems to, then that or something similar will open up the possibility of Relativistic speeds in the very near future. So we may be steadily moving to a point where this is not "hypothetical".

Too many unknowns at this point in time to consider nascent technologies a serious option. Bussard Ramjets were the theoretical possibility for interstellar travel in my youth, but turned out to be unfeasible. The technology to reach any body in solar system exists already; it would just be fiendishly expensive and require years of preparation. A spacecraft with a constant acceleration of 1.1 gravities would reach .77 the speed of light in a year; at .1 gravities a hundred years.

Edited January 20, 2017 by Hammerclaw

[lost_shaman]

1 hour ago, Hammerclaw said:

Too many unknowns at this point in time to consider nascent technologies a serious option. Bussard Ramjets were the theoretical possibility for interstellar travel in my youth, but turned out to be unfeasible. The technology to reach any body in solar system exists already; it would just be fiendishly expensive and require years of preparation. A spacecraft with a constant acceleration of 1.1 gravities would reach .77 the speed of light in a year; at .1 gravities a hundred years.

That is your opinion. It is also yet to be determined but everything seems to be pointing in the EM Drives direction. 

Where did you get your math?

 

[+Hammerclaw]

33 minutes ago, lost_shaman said:

That is your opinion. It is also yet to be determined but everything seems to be pointing in the EM Drives direction. 

Where did you get your math?

 

My K&E slide rule,  1.1 Gravity acceleration is about 10.787 meter/square second [m/s2]. Here's a website that help you visualize it.      http://space.stackexchange.com/questions/840/how-fast-will-1g-get-you-there

[lost_shaman]

2 hours ago, Hammerclaw said:

My K&E slide rule,  1.1 Gravity acceleration is about 10.787 meter/square second [m/s2]. Here's a website that help you visualize it.      http://space.stackexchange.com/questions/840/how-fast-will-1g-get-you-there

Ok. Let me quote Wikipedia...

https://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration

"At a constant acceleration of 1 g, a rocket could travel the diameter of our galaxy in about 12 years; if the last half of the trip involves deceleration at 1 g, the trip would take about 24 years. If the trip is merely to the nearest star, with deceleration the last half of the way, it would take 3.6 years."

 

^{Funny, guess somebody should edit that Wiki page.}

 

 

[+Hammerclaw]

1 hour ago, lost_shaman said:

Ok. Let me quote Wikipedia...

https://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration

"At a constant acceleration of 1 g, a rocket could travel the diameter of our galaxy in about 12 years; if the last half of the trip involves deceleration at 1 g, the trip would take about 24 years. If the trip is merely to the nearest star, with deceleration the last half of the way, it would take 3.6 years."

 

^{Funny, guess somebody should edit that Wiki page.}

 

 

Dude, the galaxy is approximately 100,000 light-year's in diameter. A light-year is the distance light travels in a year. Nothing we know of to date can exceed the speed of light. Do the math for Chrissakes! Space technology today has fundamental theoretical limits based on the practical problem that an increasing amount of energy is required for propulsion to accelerate a spacecraft anywhere near relativistic velocities. Collision with even a small piece of space debris or even particulate matter at such speeds would  be catastrophic. We can speculate there will be future solutions to these problems and in popular culture we already do; it's called science fiction. 

Edited January 20, 2017 by Hammerclaw

[lost_shaman]

14 hours ago, Hammerclaw said:

Dude, the galaxy is approximately 100,000 light-year's in diameter. A light-year is the distance light travels in a year. Nothing we know of to date can exceed the speed of light. Do the math for Chrissakes! 

You seem to be completely missing the point that Time is Relative, it slows down as velocity increases. This is my pet peeve, it is irksome to me when someone spouts this out like you've done here without acknowledging Relativistic effects like Length Contraction and Time Dilation among others. Telling me to "do the math" while you ignore Relativistic effects is ridiculous. You surely must be familiar with the Twin Paradox? This stuff is over a hundred years old and basic Special Relativity 101.

https://en.wikipedia.org/wiki/Twin_paradox

15 hours ago, Hammerclaw said:

Space technology today has fundamental theoretical limits based on the practical problem that an increasing amount of energy is required for propulsion to accelerate a spacecraft anywhere near relativistic velocities.

When you say "increasing amount of energy" I assume you are ( unnecessarily ) worried about Relativistic Mass. It isn't that more energy is needed, its that more and more energy is being translated into Length Contraction and Time Dilation as opposed to acceleration as observed from a separate reference Frame. A Starship for example that was accelerating would never notice anything other than they would feel themselves accelerating as normal.

I hate it when people get confused about all this and adamantly argue about Mass. This is completely observational and not something you would ever have to consider if you were accelerating towards a distant destination.

16 hours ago, Hammerclaw said:

Collision with even a small piece of space debris or even particulate matter at such speeds would  be catastrophic.

 Sure I don't disagree. I assume we will plan for it, strive to mitigate if it happens, but its very unlikely. 

 

[Frank Merton]

Time slows and distance and mass increases as one approaches the speed of light, but only within the framework of the thing accelerating.  The rest of the universe goes on as normal.  Hence the time dilation effect does you little good and those back home none at all.  (The real effect is not that time slows down, but that your motion in time is transferred into motion in another dimension).

[+Hammerclaw]

A feature that emerges from special relativity dictates, as something increases velocity, the mass in motion increases compared with its mass at rest, as determined by multiplying its mass at rest by the Lorentz factor. The increase in relativistic mass makes all the energy used to speed up the object less effective at increasing velocity..

As the object starts to reach real fractions of the speed of light , the amount of energy going into making the object more massive increases exponentially.

This is why nothing can travel faster than light or near lightspeed. More  energy applied to the object results in increased mass not velocity.. Mass and energy are one and the same.

[+Hammerclaw]

On ‎1‎/‎19‎/‎2017 at 8:33 PM, psyche101 said:

He is talking about Time Dilation. Makes it theoretically possible for us to travel to the centre of the galaxy in one life span, in fact I have seen theory that brings the trip down to 12 years, LS may have that link as he has provided it before, just the people on earth would have to wait through conventional time to hear about the trip. No difference to them. 

A very long wait on the order of tens of thousands of years.

[lost_shaman]

12 hours ago, Hammerclaw said:

A feature that emerges from special relativity dictates, as something increases velocity, the mass in motion increases compared with its mass at rest, as determined by multiplying its mass at rest by the Lorentz factor.

Remember that this is Observational. An Observer would say it seems that Mass is increasing, if you were onboard a Ship that was traveling at Relativistic velocity you would not notice any Mass increase. An Observer would say that Starship's Mass must be increasing because its engines are running but it's speed as we measure it is only just slightly increasing as it nears (c) light speed.

 

12 hours ago, Hammerclaw said:

The increase in relativistic mass makes all the energy used to speed up the object less effective at increasing velocity..

As velocity increases more energy goes toward Time Dilation and Length Contraction. 

 

12 hours ago, Hammerclaw said:

As the object starts to reach real fractions of the speed of light , the amount of energy going into making the object more massive increases exponentially.

 

This I believe is were so many people get confused. This is what an Observer would see and how an Observer would explain the situation. A Traveler on a Starship would never notice any Mass increase, they would see Length Contraction and experience Time Dilation. These effects are determined by the Lorentz contraction. 

 

 

 

Edited January 21, 2017 by lost_shaman

[+Hammerclaw]

Time dilation has nothing to do with the actual physics involved governing movement. What you merely observe from inside the ship is non sequitur.

 

[lost_shaman]

21 minutes ago, Hammerclaw said:

Time dilation has nothing to do with the actual physics involved governing movement. What you merely observe from inside the ship is non sequitur.

 

What are you even talking about? Time Dilation is central to Special Relativity. This stuff is the "actual physics involved".

[Maureen_jacobs]

You are now telling me that you have had the phone number all along and now you decide to contact them?

[+Hammerclaw]

11 hours ago, lost_shaman said:

What are you even talking about? Time Dilation is central to Special Relativity. This stuff is the "actual physics involved".

Yes, but all you're talking about is perceptual reality from inside the ship, not the actual physics involved acting on the ship in normal space-time. Although time slows for the passengers it doesn't for the ship itself. It is still governed by the laws of physics and transits space in normal time. It is still governed by the limitation of achieving only a fraction of light-speed and a journey that would take hundreds of thousands of years or more to span the galaxy.

[lost_shaman]

8 hours ago, Hammerclaw said:

Yes, but all you're talking about is perceptual reality from inside the ship, not the actual physics involved acting on the ship in normal space-time.

No this stuff is the actual physics.

 

8 hours ago, Hammerclaw said:

Although time slows for the passengers it doesn't for the ship itself. It is still governed by the laws of physics and transits space in normal time.

Yes it certainly does. And other strange things happen such as distances shrink (length contraction). But you can see for yourself that these effects are real and affect spacecraft because our GPS satellites, for example, have to account for both Time Dilation and being further away from Earth's Mass than ground clocks to maintain accuracy.

http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html

8 hours ago, Hammerclaw said:

It is still governed by the limitation of achieving only a fraction of light-speed and a journey that would take hundreds of thousands of years or more to span the galaxy.

That is what an Observer would Observe. It is not what Space Travelers at Relativistic velocities would experience.

[Tatetopa]

On 1/19/2017 at 10:20 PM, Hammerclaw said:

My K&E slide rule,  1.1 Gravity acceleration is about 10.787 meter/square second [m/s2]. Here's a website that help you visualize it.      http://space.stackexchange.com/questions/840/how-fast-will-1g-get-you-there

Before calculators were a dime a dozen, I had a K&E wooden Decilon and a plastic high class log log duplex decirtrig.  That was back when physics was concepts and orders of magnitude with a couple of significant decimal places.

[+Hammerclaw]

4 minutes ago, Tatetopa said:

Before calculators were a dime a dozen, I had a K&E wooden Decilon and a plastic high class log log duplex decirtrig.  That was back when physics was concepts and orders of magnitude with a couple of significant decimal places.

A vanishing art, from back when mathematics were a thought process instead of punched into a calculator.