Searching for Earth Like Planets

[Verusamore]

arriving in 2014 , what would that be in km's .

What are the optimists hoping for with the 67p/churyumov-Gerasimenko comet ?

 

thanks .

[us.2u]

Well I don't think it's cheap mars-bars (joking) really I think it's a case of seek & let's see what we find......

[ecoli]

Could humans be able to adapt to gravity differences on different planets. Astronaughts that come back from trips have to get used to earth gravity again' date=' so could humans do this on another planet? (provided the differeces are too great)[/quote']

 

I repeat my question...

[Martin]

Could humans be able to adapt to gravity differences on different planets. Astronauts that come back from trips have to get used to earth gravity again' date=' so could humans do this on another planet? (provided the differeces are too great)[/quote']

 

Did you mean to say "provided the differeces are too great"

 

or did you mean "provided the differeces are NOT too great"

 

I think you might rephrase the question more quantitative-like and say

 

over what range of planet gravity can humans adapt, without genetic alteration?

 

in metric, a gee is 9.8 meters per second per second

could humans adapt to living on a TWO GEE planet?

could humans adapte to living on a HALF GEE planet?

 

would women give birth normally?

would children grow up normally?

would people develop bad backs, spine problems, knee problems, trouble with circulation in the legs? heart disease? bone loss.

 

or is the medically and reproductively safe range more narrow, like

maybe 0.8 gee to 1.2 gee?

 

personally I think that humans are very adaptible and they would adapt very well at least in the narrower range 0.8 to 1.2 gee.

 

Coli, what did you have in mind? How does this question connect to the discussion? It is an interesting question and my answer is just a casual guess. i would like to get some more reliable information about it.

[Ophiolite]

Ah, I thought I had replied. The honest answer to this is that we don't know. (I take it that your last sentence is meant to read are not too great.)

We would have no problem adapting to Martian gravity or lunar gravity. Could we retunr from these to Earth if we had lived there for decades, not years? That could be a najor problem, so I think you have to distinguish between exploration and colonisation.

For heavier planets I imagine we could handle something like 1.2 gor 1.3g indefinitely. If we were willing to accept that we would probably never get over feeling heavy, and accepting the fact that it would likley reduce our lifespan.

Now, introduce drugs, genetic engineering and the like and those problems diminish.

However, we spent three billion years adapting to a 1g environment, we must expect complications when we move out of that environment.

 

By the way, I'm not quite sure what the gotcha was for.

[Martin]

Ophi,

you know those manpowered flight aircraft that you pedal

 

Imagine living on a planet with half the gravity so that the

wings of aircraft need only be half the size (or less)

and you dont have to pedal so hard

 

Flying bicycles! It could be a lot of fun.

[Ophiolite]

Heinlein, I think, had pedal powered flying games in domes on the moon. And other authors have had their characters strap on wings in O'Neill colonies and fly around. There is also a great bit in Rendezvous with Rama by Clarke, where the hero is trapped atop a 'cliff' several hundred meters tall, that he has to get down now. (Rama, if you have not read the book is a hollow alien artifact, spinning to create an artifical gravity). He realises that with the reduced 'g' he can just junp off and hit the 'water' not much harder than a twenty foot jump on Earth.

In short, low gravity would be fun. Its the high gravity we wouldn't like.

[soulestada]

I have noticed that people have been focusing on the characteristics of the planets (Jupiter-sized", etc.), but say nothing about the sun that it may orbit around. This is equally important. If it is an O, B, A, or F-class, life will probably not exist in such a system---at least not in an Earth-sized orbit for one simple fact, which is radiation. The hotter a star is, the higher the radiation output, especially in the higher bands like UV, which is deadly to life. If the star is an M-class, a planet would have to orbit extremely close to get warm, and the gravity of the star would probably rip it to bits. Just a speculation.....

[syntax252]

I really don't see this as a waste of money because the amount of money spent is relitively small.

 

I would rather see a Mars colony established and even a study to see if terra forming is feasable on Mars. In the Solar system, Mars is our best shot.

 

But in the overall sense of how government money is spent, the exploration of space is a minor expense.

[Anarchaus]

I have noticed that people have been focusing on the characteristics of the planets (Jupiter-sized", etc.), but say nothing about the sun that it may orbit around. This is equally important. If it is an O, B, A, or F-class, life will probably not exist in such a system---at least not in an Earth-sized orbit for one simple fact, which is radiation. The hotter a star is, the higher the radiation output, especially in the higher bands like UV, which is deadly to life. If the star is an M-class, a planet would have to orbit extremely close to get warm, and the gravity of the star would probably rip it to bits. Just a speculation.....

 

true, but not neccisarily, a large star has more radiation pressure, so earth like planets would form farther out, because the dust is blown outwards, it all has to do with the ecosphere of the solar system, a earth sized planet(+ or -1.5 earth mass) that is warm enough to have liquid water is good enough to have life, and if it doesn't its good enough for us to move on in.

 

The bigger the star, the farther out the planet has to be to support life(not too hot, not too cold). Considering that all the solar systems in the universe rely on more or less the same process in forming, i have little doubt that we will eventually find earth like planets. now about those aliens....

[Sayonara]

If the star is an M-class, a planet would have to orbit extremely close to get warm

Is this part of our classification system, or do you actually mean Min-shara?

 

[soulestada]

It's part of the classification system: O, B, A, F, G, K, and M (Oh, Be A Fine Girl, Kiss Me). Class-M stars are the reddist, coolest, and smallest. The Sun is a class-G star. I have no idea what Min-Shara is.

[Sayonara]

It was a "pah, Vulcans" joke

 

n/m

[soulestada]

Oh! Duh! Don't know any Vulcan, but I do like Star Trek, my friend!

[Sayonara]

Min-shara is what the M stands for in "M-class planet". It means habitable, or something.

[boxhead]

but is it possible that we find :life: there ?

[soulestada]

The bigger the star' date=' the farther out the planet has to be to support life(not too hot, not too cold). [/quote']

Okay, here's the bad thing I see with big stars supporting life---he star's life time. A star double the size of our own (class-A) will use up it's hydrogen twenty times faster and burn out in about 500 million years. It took at least 500 million years for life to form on this planet, so I think that the size of a star is telling.

[Asimov Pupil]

What's the problem with having jupiter sized earth like planets?

 

Even if we did find such planets' date=' what would we do with the info, since we dont have means of space travel sufficiently fast enough to take us to those planets.

 

In my opinion: pointless waste of money. Maybe we should focus more on pluto. Or develop better propulsion systems.

 

Encrypted[/quote']

 

i'd prefer Europa myself, but i alway thought is was the distance of the gas Giants from a G-2 star. a basic copy of our solar system

[island]

Originally Posted by Anarchaus

The bigger the star, the farther out the planet has to be to support life(not too hot, not too cold).

 

This is an interpretation of the anthropic principle, and you can use it more-broadly to predict where life is *more-probable* or more likely to be found.

 

For example, it's a hard known fact that the *balance* between extremes that you've described is inherent to every single anthropic coincidence.

 

In every case there is a fine range of potential which derives an ecosystematic balance, like Earth exists *between* Venus and Mars, our two nearest sister/brother planets that almost made it, but didn't quite make the grade.

 

Venus and Mars are entirely necessary to the ecosystematic balance, in other words, so you should look for this range and its ecosystematic balance if you want to find life elsewhere in the universe, so you should look on the bands of spiral galaxies that are *about* the same age as ours, since older or newer systems exist outside of this narrow range or... plane of life

 

This affects the probabilities because the principle indicates that bands of spiral galaxies that exist within the described, "relevant spectrum of potential" are analogous to "houses for life" and so life is extremely less-probable outside of this fine range of potential.

 

You can research the ever growing list of "cosmic" or "anthropic coincidences" on the net, but beware that the physics is sorely abused in the creation/evolution "debate"... by one side... and dismissed out of hand without rational consideration by the other side.

 

Ignore all that, and take note that the coincidences for life are not only balanced, but they are also balanced on the point of a needle, and would run very far away from our wildest dreams for the conditions that are necessary for life, if things weren't *near* perfectly balanced. This is important because "life as we know it"... is more likely to be the only way that life can exist because of this, so arguments for "other possible configurations" don't count for much:

 

Like finding a pencil balanced on its point:

http://abyss.uoregon.edu/~js/21st_century_science/lectures/lec28.html

 

Also relevant: Dirac's Large Numbers and the Cosmological Constant

[Crusty_Ass]

so how do they know wheter or not its earthlike?

Light spectography. Take the spectogram of liquid water or water vapour and see if you can find it out there. Absolutely not foolproof but a nice start. Next step could look for stuff like chlorophyl and complex carbohydrates. But that requires finding rocks first.

 

Lots of the planets we have found are close in super-Jupiters.

Only because current detection methods only detect those types.

We can't see the small ones yet. Nor can we see those that take 20 years for one orbit.

What's the problem with having jupiter sized earth like planets?

 

BTW, having habitable planets much bigger than Earth isn't impossible. Most of the Earths mass is made up of Iron, which is a relatively heavy element. Half of the table of elements is lighter than Iron.

 

Since the mass of a planet creates it's gravity, you could have a ball of mostly aluminium and other stuff that's 4 times the size of Earth but still has the same gravity as Earth.

 

One thing we have learned from the discovered exoplanets is that they keep surprising us.

 

In my opinion: pointless waste of money. Maybe we should focus more on pluto. Or develop better propulsion systems.

So are corporate tax-breaks. How much do those cost this year alone again...?

 

Give us a figure for how common they are, and therefore improve our estimates for the abundance of life.

 

That's funny. Old estimates 'hoped' for roughly one in ten stars having one planet. They calculated that just in this galaxy alone several million intelligent civilizations would exist over the course of the age of the galaxy.

Now we have probably several planets per star to add to that calculation. My guess is: Life is everywhere. In incredible abundance and diversity.

 

I think by earth like.....the author of this thread means planets able to support life.....life could evolve on a planet whose gravity is stronger than earth's. Plus....we have found life forms on the bottom of our oceans that live near volcanoes...and i'm not sure about this: some of them use sulphur like how we use oxygen...

Just imagine a supergiant planet with 5 G gravity, liquid metal and a silicon-based evolutionary process....Life goes where it has time and energy.

 

As for SETI.......what would we do if we did find life?

We'll probably try selling them stuff.

 

If they could support human life they will have to be, for the reasons explained in my earlier post, similar in size to the Earth, and at the right distance from their primary. In the Solar System only Earth truly fits the bill. Venus and Mars could have made it if their distances or early histories had been a little different.

well similar in size is not required, similar in gravity is more important. This is also the main reason why Mars is a 'failed' Earth. Being only 1/3 as big as Earth, it lacked the gravity to contain an atmosphere. Even Earth vents about 5000 tons of atmosphere daily into space.

Mars used to have running water, in large amounts. For that you need temperature or air pressure. We know the Sun wasn't as hot as it is now, so that leaves only one thing to have created running water on Mars: an atmosphere.

 

Well in 2007 let's all be enthralled by what the Keplar telescope relays to us in info.

Results will come in very slowly over many years, so don't hold your breath.

 

Could humans be able to adapt to gravity differences on different planets. Astronaughts that come back from trips have to get used to earth gravity again, so could humans do this on another planet? (provided the differeces are too great)

I think up to 1.5 G would be reasonable. And we have absolutely no idea what the minimum amount of gravity needs to be.

 

I would rather see a Mars colony established and even a study to see if terra forming is feasable on Mars. In the Solar system, Mars is our best shot.

If we want to terraform Mars we need to weigh it down a bit to sustain an atmosphere. Smash some asteroids into it.

 

Okay, here's the bad thing I see with big stars supporting life---he star's life time. A star double the size of our own (class-A) will use up it's hydrogen twenty times faster and burn out in about 500 million years. It took at least 500 million years for life to form on this planet, so I think that the size of a star is telling.

That's an important issue. But the galaxy is very diverse. For instance, the distance between us and Aplha Centauri is 4.6 lightyears. But for a lot of stars in our galaxy that distance is much smaller, sometimes less than a lightyear. So cross-pollination is quite possible for stars that are very close to each other.

And at the same time, life on Earth is over 3.5 Billion years old, but that also means we can safely assume life in our galaxy is 3.5 Billion years old. Probably a lot older. I think it's quite likely that life is now much more present in absolute terms than it was 3.5 Billion years ago, accros the entire galaxy. This would make not only cross-polination much more likely, but also the dispersal of life-precursors, stuff like proteins, carbohydrates etc. Once you've got those complex chemicals in place, the creation of life would very likely go a lot quicker.

 

Do notice that I use a lot of probably's and likely's, because in truth, nobody knows. But I think that life is simply a form of complexity, a form of entropy that just tends to get everywhere. We see that happen al the time on Earth, irrespective of habitat. So why should the galaxy be any different, besides being amazingly bigger and more diverse?

[us.2u]

Crusty Ass I like your posts especially life in abundance & maybe there is ETI out-there & proberly super to ours & that's why they avoid us; coz even SETI can't pick them up! Either that or we're definately sadly ALONE!...us.2u

[Ophiolite]

Nice post CA. I share your view that life may be abundant, but the bulk of it (pun intended) will be microbial.

I don't rule out the possibility of non-carbon life, but I would be amazed by it.

There was factual item in your post I think was in error.

If we want to terraform Mars we need to weigh it down a bit to sustain an atmosphere. Smash some asteroids into it.

Now smashing comets into Mars to provide an atmosphere and hydrosphere would work' date=' but you aren't going to effect a significant [u']mass gain[/u] even if you smash all the asteroids in the solar system into it.

[island]

Crusty Ass I like your posts especially life in abundance & maybe there is ETI out-there & proberly super to ours & that's why they avoid us; coz even SETI can't pick them up! Either that or we're definately sadly ALONE!...us.2u

 

The physics principle that I gave indicates that this is not correct, becuase all life formed at approximately the same time in the evolution of our universe, for that reason, so ET's technology is likely to be no more advanced than ours, and radio signals have been enroute for about as long as ours have as restricted by the speed of light.

 

This means that everybody's radio signals will start reaching everybody else at "approximately" the same time, and while nobody will be in contact with everybody, everybody will be in contact with somebody... so first contact is predicted to be one hell of a lot bigger than anybody ever expected.

 

*key erie music*... The Awakening

[RedAlert]

I agree with Crusty Ass and Encrypted.

[Ophiolite]

becuase all life formed at approximately the same time in the evolution of our universe, for that reason, so ET's technology is likely to be no more advanced than ours,

Are you serious? You must be winding us up - right? This is incorrect on so many levels I don't know where to begin. Please tell me you're joking.