Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Habitable Extra-Solar Planets?
#1
Here is something interesting, if anyone is fascinated in the possibility of life existing on other places in the galaxy: Astronomers find new planet capable of supporting life.

Quote:The planet lies in what they describe as a 'habitable zone', neither too near its sun to dry out or too far away which freezes it.

And the discovery could help answer the question of whether we are alone in the universe, which has been plagued astronomers and alien fanatics for years.

Scientists found the planet, Gliese 667Cc, orbiting around a red dwarf star, 22 light years away from the earth.

Red dwarf stars are the most common stars in the neighbourhood of the sun, usually hosting planets called gas giants, which are not composed of rock matter.

Re-analysing data from the European Southern Observatory, the astronomers found Gliese 667Cc is a solid planet with roughly four and a half times the mass of Earth.

The University Göttingen and University of California scientists have calculated the planet recieves ten per cent less light from its red dwarf star than the Earth gets from the Sun.

As the light is in the infrared area, the planet still receives nearly the same amount of energy as the Earth, meaning water could be liquid and surface temperatures could be similar to ours.

Astronomers are hailing the plant as the 'Holy Grail' of discoveries, as 20 years ago scientists were still arguing about the existence of planets beyond our solar system.

Since the discovery of the first extrasolar planet in 1995, astronomers have confirmed the existence of more than 760 planets beyond the solar system, with only four believed to be in a habitable zone.

One of the most successful tools of planet hunters is the High Accuracy Radial Planetary Searcher (HARPS) telescope, which measures the radial velocity of a star.

Scientists using this telescope analyse the small wobbles in a stars motion caused by the gravitational response of a planet, determining the position and size of a planet indirectly.

Currently, they can detect planets which are 3-5 times the mass of the Earth but, in the future, they could detect planets which are smaller than twice the mass of Earth.

Steven Vogt, an astronomer from the University of California, said: "It´s the Holy Grail of exo-planet research to find a planet orbiting around a star at the right distance so it´s not too close where it would lose all its water and not too far where it would freeze.

"It´s right there in the habitable zone - there´s no question or discussion about it. It is not on the edge. It is right in there."

Guillem Anglada-Escudé, of University Göttingen, Germany, said: "With the advent of new generation of instruments, researchers will be able to survey many dwarf stars for similar planets and eventually look for spectroscopic signatures of life in one of these worlds."

You know, this is all just great. But if we are thinking of habitable planets, the fact that this one has over four times the mass of our world, should we exclude it from that list? I'm not sure what the gravity on that world would be, but it would certainly be more than twice the gravity here. Does anyone know how gravity increases as mass goes up?

Also, orbiting a red dwarf, and being within its habitable zone, would require it to be closer to the star. Does this mean it will be tidally locked, or will it revolve like ours?

But lastly, if we are only able to detect much larger planets, that have much greater mass than ours, wouldn't that automatically eliminate new ones from being potential colonies in the future? I would think that this finding would automatically eliminate it from serious study, if we are looking for habitable planets.

Kepler Home Page

___________________________________________________________________________________________________
All men are frauds. The only difference between them is that some admit it. I myself deny it.
H. L. Mencken
Reply
#2
Yes, there is a difference between planet capable of hosting life and habitable ones.

I assume that at 4.5x the Earth's mass, gravity should be 4.5x that of the Earth.
HUmans who would land there would fall on the ground like jellyfishes on a beach, unable to move.
You would weight 4.5 your actual weight. Better go on diet before going there.

Even sending robots would be difficult since all their arms and wheels would have to be 5x time stronger than they need to be on Earth. It would be a huge effort to raise an antenae or a solar panel.

But live could exist and even an intelligent one, just more different than ours.

22 light years is like right next to us.
It's almost accessible with a small probe...
Reply
#3
The Tidally locked question is an interesting one.. Yes, the planet would have to be a lot closer to the star, but the star is much smaller as well. Does anyone know the physics involved here? I'm terribly curious.

As for colonization... We're not even going to be able to do a generational attempt at that until we can detect smaller planets.

Never the less, given the energy required to leave a 4.5G planet, and assuming intelligent life, it might be fun to drop a probe into their orbit and taunt them. "Can't get up here, can ya? Well we're gonna colonize your entire solar system and keep you pinned in. And there's nothing you can do about it. Enjoy your gravity well! Suckers."
Reply
#4
If this planet does support life what ever lives there would probably make dinosaurs look like mice in comparison.
The true purpose of democracy is not to select the best leaders — a clearly debatable obligation — but to facilitate the prompt and peaceful removal of obviously bad ones. 
Reply
#5
They start to identify so-called "habitable" systems only last few years. Give it time. The real search will start after lunar base is established.
Reply
#6
Fred, 4.5 times the mass will not mean 4.5 times the gravity. You are using a 'static' analysis. Oh lord, I have forgotten the proper phrase to define this, but as things increase, the effect gradually decreases.

I'm just taking a guess, but the gravity would most likely be somewhere around three to three and an half gravities. Its just a guess, but I'll bet you there is some sort of scientific equation in order to get to the correct answer. That's why I asked if anyone knew.

"Pix" there is also a physics equation that would govern tidally locked celestial bodies, but I don't know it either. My guess is that the planet may not be 'locked' as is our moon, because the red dwarf is a fairly active/hot one, as red dwarfs go. But something with that mass that close to the star means that most of that system's mass is a lot closer to the star than ours is.

Usually for certain types of stars, and their energy output, satellite orbits will be determined by where they are located, and how they are able to attract other material, without that material being swallowed up by the star. So a planet closer in would have less effect on asteroids, comets, or other large objects, because it lacked the mass to draw them in. That is why Jupiter captures so much debris compared to all other planets. It strategic location and high mass, is most likely due to its position relative to the sun. Something having 4.5 earth mass, and that close means the system is going to be a bit stranger than ours.
___________________________________________________________________________________________________
All men are frauds. The only difference between them is that some admit it. I myself deny it.
H. L. Mencken
Reply
#7
(04-27-2012, 04:24 PM)WarBicycle Wrote: If this planet does support life what ever lives there would probably make dinosaurs look like mice in comparison.

Not so sure about that. One thing is certain; terrestrial life will not only be massive, but it will be very low to the ground. If they are tall, a simple fall would kill/crush it. So their height would be determined by the mass of the creatures.

___________________________________________________________________________________________________
All men are frauds. The only difference between them is that some admit it. I myself deny it.
H. L. Mencken
Reply
#8
Saturn has almost 100 times the mass of earth, but almost the same g- force. Surface is a long way from the centre of gravity. You can use Newton's equations to figure out g at the surface of this planet, what you need is its radius.

Life on earth comes in all shapes and strengths for the same gravity. Wouldn't be any different under 3g. Life simply adapts, and develops stronger compounds for large life-forms.
"You know, Paul, Reagan proved that deficits don't matter." Dick Cheney
Reply
#9
(04-28-2012, 06:04 AM)quadrat Wrote: Saturn has almost 100 times the mass of earth, but almost the same g- force. Surface is a long way from the centre of gravity. You can use Newton's equations to figure out g at the surface of this planet, what you need is its radius.

Life on earth comes in all shapes and strengths for the same gravity. Wouldn't be any different under 3g. Life simply adapts, and develops stronger compounds for large life-forms.

Makes sense. But I still can see a 'select advantage' for any form to develop height wise, depending on the gravitational force. Either that, or the organism would have to be flowing, and not solid. In fact, one might see both representations on the same high gravity planet.

Natural Selection almost always goes in many different directions, and the most successful keeps reproducing, making it a success. The Law of Natural Selection is just as iron clad as the universal law of mathematics. Natural Selection will work the same anywhere in the universe, regardless what Ron may try to deny. S5

___________________________________________________________________________________________________
All men are frauds. The only difference between them is that some admit it. I myself deny it.
H. L. Mencken
Reply
#10
I searched on the internet about the gravitation formula and it's a bit more complicate that you think.
Gravity is proportional to the mass of the objects, but it also decreases by (inversely proportional to) the square of the distance separating the gravity centers of both objects.

In the case of men walking on a planet (or trying to crawl painfuly) their weight is not calculated at the surface of the planet but by how far the surface is from the center of gravity (the geometrical center if the planet is round and homogeneous).
That measn that while the mass of the planet is 4.5x that of the Earth, weight felt on the surface would be, as you said, something like only 3.5x because the surface is further from the center than on Earth.

Now let's say the new planet is composed of lead at 90%, its mass would be 4.5x Earth's mass, but its volume smaler. As a result not only the mass in action would be greater but poeple would be walking closer to the center of gravity. Weight at the surface in this case would be higher than 4.5x, maybe 6.5x!

On Satrun, Quadrat said that wieght is similar to Earth. That's because Saturn's surface is very far from its gravitational center.
In fact as a gazeous planet it has no solid surface (or very deep beneath its atmosphere if any), what we mean by Saturn's or Juptier's surface is in fact the visible top of their atmosphere. Not somthing we could test our walking capabilities on.

WB Wrote:If this planet does support life what ever lives there would probably make dinosaurs look like mice in comparison.
Like John, I'd rather imagine these dinosaures like giant flat worms, growing as little as possible in height and with very short legs or just crawling on their belly.
Most of these animals would move slowly and horizontaly.

Trees would look like bonzais.

A more concentrated atmosphere would compensate for weight. Breathing more oxygen at once could help.

In water, presure would like in a 3 miles deep ocean here. Our deep water fishes would probably be happy in a pound at the surface of this planet.
Reply
#11
Wouldn't make much difference to trees. Trunks and branches would be a little more massive to grow tall, that's all. If you assume 3g, the pressure under water would be 3 times higher than on earth at the same depth. It's buoyancy would compensate just the same, if you go for a swim, you don't feel your weight anymore. The waves are smaller if we assume atmospheric pressure and winds like here. I could imagine humans going there to have to spend most of the day standing up to the neck in water at the beginning, most would adapt quickly by strengthening the muscles, and bones embeding more calcium. Physically unfit people should have the common sense not to go there. There's probably in principle no reason why evolution shouldn't come up with extremely strong structures made from say carbon nanotubes, or metal. It didn't so far here, but if trees had to grow two miles high, it would.
"You know, Paul, Reagan proved that deficits don't matter." Dick Cheney
Reply


Possibly Related Threads…
Thread Author Replies Views Last Post
  Orphan Planets John L 5 2,166 07-04-2011, 06:06 PM
Last Post: John L
  First potentially habitable planet near Earth John L 3 1,745 09-29-2010, 09:47 PM
Last Post: John L
  Hundreds of Earthlike Planets Discovered John L 19 5,281 07-27-2010, 08:15 PM
Last Post: Armadillo

Forum Jump:


Users browsing this thread: 1 Guest(s)