Exoplanets (split from Science videos)

[Airbrush]

On 6/8/2019 at 3:29 PM, Moontanman said:

Is there a place on the site for videos like this and if not should there be? 

 

 

During what period of time were these planets found?  Are these the most recent discoveries?  Of all the terrestrial planets found, how many of them are so much like Earth that we could survive on the surface without help from space suits?  As far as I know, we have not discovered any Earth 2.0.  Maybe that explains the Fermi Paradox?

[Moontanman]

1 minute ago, Airbrush said:

During what period of time were these planets found?  Are these the most recent discoveries?  Of all the terrestrial planets found, how many of them are so much like Earth that we could survive on the surface without help from space suits?  As far as I know, we have not discovered any Earth 2.0.  Maybe that explains the Fermi Paradox?

I don't think that problem really does solve the fermi paradox. It assume a planet must be just like Earth but life on Earth has adapted to the Earth. No reason to assume that life elsewhere couldn't adapt to somewhat different conditions.. 

[Airbrush]

4 minutes ago, Moontanman said:

I don't think that problem really does solve the fermi paradox. It assume a planet must be just like Earth but life on Earth has adapted to the Earth. No reason to assume that life elsewhere couldn't adapt to somewhat different conditions.. 

Yes there could be "life" on frozen planets.  You will probably not find life on hot Jupiters.  We may find life under the surface of frozen planets.  Correct me if I'm wrong, but I think of the thousands of exoplanets discovered, we still have not found a planet as nice as Earth, right?

Edited June 16, 2019 by Airbrush

[Moontanman]

Just now, Airbrush said:

Yes there could be "life" on frozen planets.  You will probably not find life on hot Jupiters.  We may find life under the surface of frozen planets.  Correct me if I'm wrong, but I think of the thousands of exoplanets discovered, we still have not found a planet as nice as Earth, right?

Actually some are pretty close even by strict standards but the standards assume quite a bit and ignore other possibilities. Super Earths for instance might very well be better than the Earth for life and could expand the habitable zone considerably. 

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

Quote

In November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs in the Milky Way,^[5][6] 11 billion of which may be orbiting Sun-like stars.^[7]

 

[beecee]

5 hours ago, Airbrush said:

Yes there could be "life" on frozen planets.  You will probably not find life on hot Jupiters.  We may find life under the surface of frozen planets.  Correct me if I'm wrong, but I think of the thousands of exoplanets discovered, we still have not found a planet as nice as Earth, right?

We have so far found a heap of near Earth sized planets that exist within the Goldilocks zone. As yet I don't think we have researched them thoroughly enough to determine their atmospheres etc. Planets in the Goldilock zones are those where liquid water can exist on the surface.

With hot Jupiters, we [astronomers]  have reason to believe in a process called planetary migration, at least early on in a stellar systems formation. Just as obviously the discovery of hot Jupiters was always going to be the easiest to find, hence the early numbers of them. Terrestrial sized planets in habitable zones came later as methodologies were refined.

5 hours ago, Moontanman said:

 Super Earths for instance might very well be better than the Earth for life and could expand the habitable zone considerably. 

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

 

The only problem with any potential life on a super Earth, is that any space endeavours would be far harder to achieve then on Earth...escape velocities and all that.

Edited June 16, 2019 by beecee

[Airbrush]

21 hours ago, beecee said:

The only problem with any potential life on a super Earth, is that any space endeavours would be far harder to achieve then on Earth...escape velocities and all that.

There could be great potential for life on Super Earths, but how comfortable would a human feel stepping out on the surface weighing twice as much, or more, as on Earth?  Such a planet may be great for life forms that evolved for high gravity.  Humans from Earth would not enjoy the heavy gravity.  So for Earth 2.0, it should be nearly the same size as Earth, or I'm not going there.

Edited June 17, 2019 by Airbrush

[Moontanman]

38 minutes ago, Airbrush said:

There could be great potential for life on Super Earths, but how comfortable would a human feel stepping out on the surface weighing twice as much, or more, as on Earth?  Such a planet may be great for life forms that evolved for high gravity.  Humans from Earth would not enjoy the heavy gravity.  So for Earth 2.0, it should be nearly the same size as Earth, or I'm not going there.

Some place I read... I think.. that humans could possibly adapt to 2gs but I am not sure where. But as I have said, why bother with planets at all? We could pack 40 5 mile long 1 mile thick Mckendrick cylinders into an area about 15 miles in diameter covered in a couple hundred meters of regolith and ices to protect from small meteors. It would look like a 15 mile wide sphere but inside it would house 30 or 40 habitats inside in a geometric pattern. I'm not sure about waste heat dissipation. That might limit the number of cylinders. All we would need that we don't have now is controlled fusion... That would be 628 square miles of living space, full earth gravity and atmosphere...  

[Airbrush]

Yes why bother with planets when you can find asteroids with water-ice and the metals necessary for industry?  Just burrow into such asteroids.  How can you excavate large volumes of rock, metal, and ice?

[Moontanman]

8 hours ago, Airbrush said:

Yes why bother with planets when you can find asteroids with water-ice and the metals necessary for industry?  Just burrow into such asteroids.  How can you excavate large volumes of rock, metal, and ice?

Dynomite! I'm sure a way would be found if we could get there! Hydrocarbons like methane would be very valuable in making habitats of large size. Use them to make graphene... But the 5 mile long and 1 mile thick ones could be made of metals for sure... 

 

[Airbrush]

On 6/19/2019 at 8:39 PM, Moontanman said:

Dynomite! I'm sure a way would be found if we could get there! Hydrocarbons like methane would be very valuable in making habitats of large size. Use them to make graphene... But the 5 mile long and 1 mile thick ones could be made of metals for sure... 

 

Dynamite will cause the material to be lost into space, or push the asteroid around uncontrollably.  You need drills and claws to gather up every precious bit of water-ice (which makes air, water, and fuel) and metals to fabricate structures.  The other benefit of being on an asteroid is you can have centrifuges for creating one g for sleep and recreation.  The workers go outside and work in zero g.

Edited June 25, 2019 by Airbrush

[Moontanman]

8 hours ago, Airbrush said:

Dynamite will cause the material to be lost into space, or push the asteroid around uncontrollably.  You need drills and claws to gather up every precious bit of water-ice (which makes air, water, and fuel) and metals to fabricate structures.  The other benefit of being on an asteroid is you can have centrifuges for creating one g for sleep and recreation.  The workers go outside and work in zero g.

Dynomite! Is a cultural reference mean to be humorous, check the spelling. But yes, we would have to develop ways of mining in zero gee. Possibly robots could do much of it with just a few humans to supervise the mining and construction of the first habitats. Then more humans could settle in those places and more robots could be used. It's the beginning of my Winnebago theory of galactic colonization...   

[swansont]

8 hours ago, Airbrush said:

Dynamite will cause the material to be lost into space, or push the asteroid around uncontrollably.  You need drills and claws to gather up every precious bit of water-ice (which makes air, water, and fuel) and metals to fabricate structures.  The other benefit of being on an asteroid is you can have centrifuges for creating one g for sleep and recreation.  The workers go outside and work in zero g.

That would depend on the local value of g, and if it's small (so that material would be lost to space) then you are going to have a hard time drilling, too, as whatever is doing the drilling will not weigh much.

[dimreepr]

2 hours ago, Moontanman said:

Dynomite! Is a cultural reference mean to be humorous, check the spelling. But yes, we would have to develop ways of mining in zero gee. Possibly robots could do much of it with just a few humans to supervise the mining and construction of the first habitats. Then more humans could settle in those places and more robots could be used. It's the beginning of my Winnebago theory of galactic colonization...   

Or the beginning of the end...

[Airbrush]

On 6/25/2019 at 7:32 AM, swansont said:

That would depend on the local value of g, and if it's small (so that material would be lost to space) then you are going to have a hard time drilling, too, as whatever is doing the drilling will not weigh much.

How about attaching high-powered cutting lasers to cut neat slices of rock, ice, and metals, to be processed.

If the asteroid is, for example, 10 miles in diameter, how many g's will that result in?  Living quarters can be a comfortable one g within a short commute.

Edited June 29, 2019 by Airbrush

[swansont]

On 6/29/2019 at 12:44 AM, Airbrush said:

If the asteroid is, for example, 10 miles in diameter, how many g's will that result in?  Living quarters can be a comfortable one g within a short commute.

6 km radius, so the volume is just under 10^12 m^3; let's assume it's 5 g/cm^3 density, (5 x 10^-3 kg/m^3) or 5 x 10^9 kg. That's around 10^-8 m/s^2 of acceleration. 1 nano-g.

A 3 kW laser will exert a force of 10^-5 N. A 1000 kg object will weigh ~10^-5 N on that asteroid. If it's lighter, it will lift off (very, very slowly)

 

(above should be 5 x 10^3 kg/m^3 and 10^15 kg, resulting in 10^-2 m/s^2, or a milli-g of acceleration)

 

 

[Airbrush]

15 hours ago, swansont said:

6 km radius, so the volume is just under 10^12 m^3; let's assume it's 5 g/cm^3 density, (5 x 10^-3 kg/m^3) or 5 x 10^9 kg. That's around 10^-8 m/s^2 of acceleration. 1 nano-g.

A 3 kW laser will exert a force of 10^-5 N. A 1000 kg object will weigh ~10^-5 N on that asteroid. If it's lighter, it will lift off (very, very slowly)

One nano-g sounds close enough to zero g for most purposes.  So the 3 kW laser will need to be strapped securely to the asteroid.  Even heavy volumes of material will be very light-weight and easy to transport to processing stations.

Edited June 30, 2019 by Airbrush

[swansont]

10 hours ago, Airbrush said:

One nano-g sounds close enough to zero g for most purposes.  So the 3 kW laser will need to be strapped securely to the asteroid. 

Which means straps that are more than 36 km long, in order to wrap around the asteroid.

Or you are firing rockets to give thrust toward the asteroid.

Setting off a small explosive or shooting it with a sabot and catching the pieces doesn't sound as bad when you consider how hard these other methods will be. 

10 hours ago, Airbrush said:

Even heavy volumes of material will be very light-weight and easy to transport to processing stations.

You have to account for changes in orbital velocity when figuring out how "easy" transport will be.

[Airbrush]

On 6/30/2019 at 7:41 AM, swansont said:

Which means straps that are more than 36 km long, in order to wrap around the asteroid.

Or you are firing rockets to give thrust toward the asteroid.

Setting off a small explosive or shooting it with a sabot and catching the pieces doesn't sound as bad when you consider how hard these other methods will be. 

You have to account for changes in orbital velocity when figuring out how "easy" transport will be.

Any means of anchoring the laser, or no anchoring at all.   Just using rockets to counter the cutting lasers thrust.  Only needs a tiny thrust right?

Because of the very low g work environment, workers could literally carry thousands of tons of material on their backs across the asteroid, to the materials dump and sorter, right?

Edited July 1, 2019 by Airbrush

[swansont]

2 hours ago, Airbrush said:

Any means of anchoring the laser, or no anchoring at all.   Just using rockets to counter the cutting lasers thrust.  Only needs a tiny thrust right?

Tiny, meaning if you miscalculate and over-thrust, you might smash into the asteroid.

2 hours ago, Airbrush said:

Because of the very low g work environment, workers could literally carry thousands of tons of material on their backs across the asteroid, to the materials dump and sorter, right?

How do you walk when there is essentially no gravity? You push on the asteroid and it accelerates away from you. There is basically no restoring force to bring you back.