Scientists find potentially habitable planet near Earth

Sep 29, 2010
This illustration released in 2009 by the European Southern Observatory (ESO) shows the planet Gliese 581e (blue). US astronomers said Wednesday they have discovered an Earth-sized planet that they think might be habitable, orbiting a nearby star, and believe there could be many more planets like it in space.

(PhysOrg.com) -- A team of planet hunters led by astronomers at the University of California, Santa Cruz, and the Carnegie Institution of Washington has announced the discovery of an Earth-sized planet (three times the mass of Earth) orbiting a nearby star at a distance that places it squarely in the middle of the star's "habitable zone," where liquid water could exist on the planet's surface. If confirmed, this would be the most Earth-like exoplanet yet discovered and the first strong case for a potentially habitable one.

To astronomers, a "potentially habitable" planet is one that could sustain life, not necessarily one that humans would consider a nice place to live. Habitability depends on many factors, but liquid water and an atmosphere are among the most important.

"Our findings offer a very compelling case for a potentially habitable planet," said Steven Vogt, professor of astronomy and astrophysics at UC Santa Cruz. "The fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common."

The findings are based on 11 years of observations at the W. M. Keck Observatory in Hawaii. "Advanced techniques combined with old-fashioned ground-based telescopes continue to lead the exoplanet revolution," said Paul Butler of the Carnegie Institution. "Our ability to find potentially habitable worlds is now limited only by our telescope time."

Vogt and Butler lead the Lick-Carnegie Exoplanet Survey. The team's new findings are reported in a paper to be published in the Astrophysical Journal and posted online at arXiv.org. Coauthors include associate research scientist Eugenio Rivera of UC Santa Cruz; associate astronomer Nader Haghighipour of the University of Hawaii-Manoa; and research scientists Gregory Henry and Michael Williamson of Tennessee State University.

The orbits of planets in the Gliese 581 system are compared to those of our own solar system. The Gliese 581 star has about 30 percent the mass of our sun, and the outermost planet is closer to its star than the Earth is to the sun. The 4th planet, G, is a planet that could sustain life. Credit: Zina Deretsky, National Science Foundation

The paper reports the discovery of two new planets around the nearby red dwarf star Gliese 581. This brings the total number of known planets around this star to six, the most yet discovered in a planetary system other than our own solar system. Like our solar system, the planets around Gliese 581 have nearly circular orbits.

The most interesting of the two new planets is Gliese 581g, with a mass three to four times that of the Earth and an orbital period of just under 37 days. Its mass indicates that it is probably a rocky planet with a definite surface and that it has enough gravity to hold on to an atmosphere, according to Vogt.

Gliese 581, located 20 light years away from Earth in the constellation Libra, has a somewhat checkered history of habitable-planet claims. Two previously detected planets in the system lie at the edges of the habitable zone, one on the hot side (planet c) and one on the cold side (planet d). While some astronomers still think planet d may be habitable if it has a thick atmosphere with a strong greenhouse effect to warm it up, others are skeptical. The newly discovered planet g, however, lies right in the middle of the habitable zone.

"We had planets on both sides of the habitable zone--one too hot and one too cold--and now we have one in the middle that's just right," Vogt said.

The planet is tidally locked to the star, meaning that one side is always facing the star and basking in perpetual daylight, while the side facing away from the star is in perpetual darkness. One effect of this is to stabilize the planet's surface climates, according to Vogt. The most habitable zone on the planet's surface would be the line between shadow and light (known as the "terminator"), with surface temperatures decreasing toward the dark side and increasing toward the light side.

"Any emerging life forms would have a wide range of stable climates to choose from and to evolve around, depending on their longitude," Vogt said.

The researchers estimate that the average surface temperature of the planet is between -24 and 10 degrees Fahrenheit (-31 to -12 degrees Celsius). Actual temperatures would range from blazing hot on the side facing the star to freezing cold on the dark side.

If Gliese 581g has a rocky composition similar to the Earth's, its diameter would be about 1.2 to 1.4 times that of the Earth. The surface gravity would be about the same or slightly higher than Earth's, so that a person could easily walk upright on the planet, Vogt said.

The new findings are based on 11 years of observations of Gliese 581 using the HIRES spectrometer (designed by Vogt) on the Keck I Telescope at the W. M. Keck Observatory in Hawaii. The spectrometer allows precise measurements of a star's radial velocity (its motion along the line of sight from Earth), which can reveal the presence of planets. The gravitational tug of an orbiting planet causes periodic changes in the radial velocity of the host star. Multiple planets induce complex wobbles in the star's motion, and astronomers use sophisticated analyses to detect planets and determine their orbits and masses.

"It's really hard to detect a planet like this," Vogt said. "Every time we measure the radial velocity, that's an evening on the telescope, and it took more than 200 observations with a precision of about 1.6 meters per second to detect this planet."

To get that many radial velocity measurements (238 in total), Vogt's team combined their HIRES observations with published data from another group led by the Geneva Observatory (HARPS, the High Accuracy Radial velocity Planetary Search project).

In addition to the radial velocity observations, coauthors Henry and Williamson made precise night-to-night brightness measurements of the star with one of Tennessee State University's robotic telescopes. "Our brightness measurements verify that the radial velocity variations are caused by the new orbiting planet and not by any process within the star itself," Henry said.

The researchers also explored the implications of this discovery with respect to the number of stars that are likely to have at least one potentially habitable planet. Given the relatively small number of stars that have been carefully monitored by planet hunters, this discovery has come surprisingly soon.

"If these are rare, we shouldn't have found one so quickly and so nearby," Vogt said. "The number of systems with potentially habitable planets is probably on the order of 10 or 20 percent, and when you multiply that by the hundreds of billions of stars in the Milky Way, that's a large number. There could be tens of billions of these systems in our galaxy."


Watch the full press briefing at the National Science Foundation. Steven Vogt of UC Santa Cruz and UC Observatories and Paul Butler of the Carnegie Institution of Washington join NSF's Lisa-Joy Zgorski to announce the discovery of the first exoplanet that has the potential to support life.

Explore further: Exomoons Could Be Abundant Sources Of Habitability

Provided by University of California - Santa Cruz

4.8 /5 (85 votes)

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_nigmatic10
1 / 5 (5) Sep 29, 2010
36 day orbit around the sun? moving pretty fast for an Earth-type.
jscroft
3.7 / 5 (15) Sep 29, 2010
Gliese 581 is a red dwarf, and so has a much cooler surface temp than Sol. The habitable zone is this a lot closer in, leading to shorter orbital periods in the zone.

Now that we've found livable real estate, how long do you suppose it'll be before Congress figures out how to tax it?
michaelick
5 / 5 (17) Sep 29, 2010
So sad the Carl Sagan is already dead. He would be happy to hear this. "A still more glorious dawn awaits us..."
thales
4.7 / 5 (12) Sep 29, 2010
Hopefully this is the beginning of quieting those who believe Earth-like conditions are incredibly rare.
Birger
2 / 5 (2) Sep 29, 2010
If the fraction of water to rock is the same as on Earth, for reasons of geometry you would have much deeper (thicker) oceans. It would be hard for volcanic islands or continents (who are built from volcanic island arches) to reach the surface. You might get bacteria living in the abyss, but without continental shelves providing shallow-water environments, evolution would have a hard time getting any further...
Royale
4 / 5 (8) Sep 29, 2010
I bet they're very common, and there's life (some intelligent) within 1000 light years; just give them some time and they'll find them...
apex01
1 / 5 (2) Sep 29, 2010
If it has 3 times the mass of Earth, then a person should weigh 3 times more on the new planet, right?
Starbound
5 / 5 (9) Sep 29, 2010
The biggest problem is that it is tidally locked. I can imagine that the near side could be totally stripped of water, having been boiled away, and most of the water would be locked up as ice on the dark side. This could have implications on crust thickness and plate tectonics. Fortunately, the planet is quite large, which might prevent atmosphere loss on the hot side. I wonder just how big the temperature difference is. Hopefully one day soon we can directly image the planet and make temperature measurements as its planetary phase changes.
jselin
5 / 5 (9) Sep 29, 2010
The line between light and dark would most likely be an extremely windy place! There is a lot of energy on the hot side that need to find its way to the cold side.
Quantum_Conundrum
4 / 5 (16) Sep 29, 2010
Apex01:

If it is earth-like composition, the answer is no.

Gravity decreases as the reciprocal of the square of distance. So a larger planet has "stronger" gravity, but because the surface is farther away, the surface gravity doesn't increase linearly with the increase in mass.

if it is 3 times as massive as earth and of the same average composition, the radius would be less than or equal to 1.45 earth radius.

So to find the proportion of surface gravity vs earth, you would then square the radius multiplier in terms of earth, and divide that into the mass in terms of earth.

so:

3/(1.45^2) = 1.427g (or slightly greater).

the reason it might be a few hundreds greater is because stronger gravity would lead to greater compressive forces on the rock. We can safely say it might be at most 1.5g for a 3 earth masses planet of same relative composition, but is probably closer to the 1.427g.
sstritt
3.4 / 5 (10) Sep 29, 2010
If it has 3 times the mass of Earth, then a person should weigh 3 times more on the new planet, right?

the acceleration due to gravity (g)= Gm/r*2 so if the radius is 1.4 times earth and the mass is 3 times, then g would be around 1.5 times earth
Quantum_Conundrum
2.7 / 5 (7) Sep 29, 2010
When you think about planetary disk (think full moon,) when you have a tidally locked planet, half the planet faces the star.

However, of this half, only around half of this disk, i.e. the inner core of this disk, directly faces the star with an incidence angle of less than or equal to 45 degrees from normal. the outter edge of the disk is at a high enough angle that more light would reflect off of it than penetrate.

so with average temps of -24F to +10F, about 1/4th of the planet's surface should be in what we would consider a "temperate" zone.

But the problem is how does the atmpshere and water on the planet behave. As stated it would seem like it should accumulate as a massive glacier on the dark side at the point farthest from the heat.

So basicly half of it will be like Enceladus, 1/4 of it will be like Mercury, and another 1/4 of it will be approximately like Canada or Alaska on earth.
Quantum_Conundrum
3.7 / 5 (12) Sep 29, 2010
Wow.

This is obviously the best candidate for our first inter-stellar planetary orbiter mission.

Assuming fusion rocketry is possible, you could get a highly automated probe there in around 67 years at 0.3c. And I mean a very complex mission, as it would require launching 10 to 15 relay probes along the way to boost the signal. Once there, it would drop several landers and dropsonde style craft into the atmospheres of each of the planets, and orbit the best candidate, mapping it. This might take a few years.

It would take 20 years for the return signal to reach earth, so probably 87 years to start getting back data at a bare minimum from launch.

Too bad we still can't even burp a controllable Fusion reaction yet...
trekgeek1
4 / 5 (8) Sep 29, 2010


Assuming fusion rocketry is possible, you could get a highly automated probe there in around 67 years at 0.3c. And I mean a very complex mission, as it would require launching 10 to 15 relay probes along the way to boost the signal. Once there, it would drop several landers and dropsonde style craft into the atmospheres of each of the planets, and orbit the best candidate, mapping it. This might take a few years.

It would take 20 years for the return signal to reach earth, so probably 87 years to start getting back data at a bare minimum from launch.

Too bad we still can't even burp a controllable Fusion reaction yet...


If it takes 87 years to get there, you might be better off just waiting and developing better propulsion systems. Could you imagine sending a vehicle and when it arrives 87 years later there is already an Earth based space craft waiting for you to arrive?
Quantum_Conundrum
2.7 / 5 (7) Sep 29, 2010
Could you imagine sending a vehicle and when it arrives 87 years later there is already an Earth based space craft waiting for you to arrive?


1) 67 years to get there, 20 years for a light speed signal to get back.

2) For several reasons involving both classical and relativistic effects, we have shown in the past that with any remotely conceivable fusion or anti-matter engine it is extremely, ridiculously impractical for an colony ship or interstellar orbiter mission to go faster than 0.3c, because energy costs go up so much more.

3)Using "fair" estimates of real world efficiency ratings for rockets, it would probably take around 100 times as much energy for main stage and braking stage to go 0.3c as compared to 0.1c. It would probably take around another 10 times as much energy to get it to 0.4c, but you'd only cut out about 17 years, or 1/4 of the time by doing so.

For the same energy cost, you could have made 10 probes and sent them to 10 different stars at 0.3c
toddao
3 / 5 (3) Sep 29, 2010
what we need to do is master cryogenic suspension, so we can send up some astronauts. what a WILD ride that would be.

i'm guessing that without warp drive or wormholes that .3 C might be the realistic speed limit for "conventional" propulsion due to increasing mass, no?
lepidoptera
3.7 / 5 (3) Sep 29, 2010
"We had planets on both sides of the habitable zone--one too hot and one too cold--and now we have one in the middle that's just right," Vogt said.
I say we name it 'Baby Bear'
Trim
2.5 / 5 (6) Sep 29, 2010
We should start learning how to clone scientists and make artificial wombs by freezing embryos at the 8 cell stage they should keep for the hundreds of years it would take to travel there. If the womb worked OK robots could act as teachers and nursemaids, if the planet was worth it. If not no real loss.
Husky
5 / 5 (5) Sep 29, 2010
now that is what i call exciting news! and so much more to come from those new telescopes coming online.
Quantum_Conundrum
2.5 / 5 (8) Sep 29, 2010
Trim:

Titan A.E.?

I suggested something better than this several months ago.

I had considered how to build a "preserver" space ship with self replicating robotic systems to terraform a planet, build cities, and re-introduce earth life from archived DNA of everything that ever lived, including all living humans.

I figured out that it SHOULD theoretically be possible to build a ship who's computer systems are guaranteed to have maintained memory for any distance of travel, and will just barely have time to re-power it's primary fusion reactor using a combination of solar energy and other ticks as it enters the targetted solar system.

It should theoretically be possible, but it requires some unorthox thinking about what we consider as a "colony ship".

All technology, DNA and cell structures would be preserved in non-volatile memory format, and life forms would be re-constructed on a per-molecule basis upon arrival as appropriate stages of terraforming have happened.
Quantum_Conundrum
1.7 / 5 (6) Sep 29, 2010
This approach was with the assumption of just 0.1c velocity, but "relatively unlimited time" since you don't actually have organics or people on board.

It could "coast" in space for thousands, ten thousands, possibly even millions of years at 0.1c before it arrives at it's destination.
MaxwellsDemon
5 / 5 (4) Sep 29, 2010
@ toddao:
The hurdles to achieving interstellar travel are truly and profoundly disparaging. Energy, for example:
“Accelerating one ton to one-tenth of the speed of light requires at least 450 PJ or 4.5 × 1017 J or 125 billion kWh, not accounting for losses.”
http://en.wikiped...r_travel

Additionally, space is full of debris that at high velocity impacts explosively:
"At 0.2c, a 100 gram particle has a kinetic energy equivalent to the explosive energy of a 40 kiloton bomb!"
"a shield the equivalent of a 10 meter thickness of solid tungsten would be required. Such a shield covering the front of our spaceship would weigh in excess of two million tons."
http://articles.a...ssic=YES

The only remotely hopeful mechanism of interstellar travel that I’ve found so far is a wildly hypothetical concept called the Alcubierre drive.
barakn
2.3 / 5 (3) Sep 29, 2010
Let the light come to you and catch it with a bigger mirror.
barkster
5 / 5 (4) Sep 29, 2010
I notice that most everybody is focusing on the planets climate, because it's been found in the "habitable" zone.

Atmospheric composition (if any) aside.... What about a magnetic field? Could it be a cold hunk of water/ice covered rock bathed in deadly solar radiation?
toddao
5 / 5 (1) Sep 29, 2010
Alcubierre drive is a facinating concept

http://www.davidd...ive.html

maybe the LHC will discover some "Di-Lithium" :)
toddao
2.3 / 5 (3) Sep 29, 2010
i also think that warp drive is the reason that UFOs can turn on a dime at high velocity without flattening the occupants. (because the ship is actually at rest) :)
Kedas
5 / 5 (5) Sep 30, 2010
They didn't mention the most important fact.
Does it have a stargate? :)
Pkunk_
1 / 5 (4) Sep 30, 2010
what we need to do is master cryogenic suspension, so we can send up some astronauts. what a WILD ride that would be.

i'm guessing that without warp drive or wormholes that .3 C might be the realistic speed limit for "conventional" propulsion due to increasing mass, no?


Don't forget that while the voyage might take 60 years , the people on board would age ~ 40 years due to relativistic effects of travelling @ 0.3c

In fact the faster you go , the slower you age. So while it may cost 10 times to go 0.3c , don't forget that not only the mission will reach there faster , but the people on board will age MUCH slower.
TechnoCore
5 / 5 (2) Sep 30, 2010
@MaxwellsDemon

In the excellent book Accelerando by Charles Stross they build a really small spaceship weighing like 500grams. I think it was riding a laserbeam, And all it contained was basically an AI. Maybe that's a way to get there fast without using up too much energy :)
MaxwellsDemon
5 / 5 (2) Sep 30, 2010
@TechnoCore: That's a fine idea. However, I'm extraordinarily greedy, and therefore require that any potential solution involve ME (or at least some human proxy) in the cockpit. Spacetime engineering appears to be the only remotely plausible concept within that constraint.

@toddao: Herman Bondi and Robert Forward have done some theoretical work on 'negative mass propulsion' that you might find intriguing. If you like the idea of accelerating without using energy, that is. Alternatively, harnessing dark energy might do the trick too.

@Pkunk: your math's all pkunked up. The Lorentz transform is sqrt(1-B^2), which at B = .3 yields a time dilation of .9539, not .6666

In spirit you're right though - at 1G a human could circumnavigate the visible universe within their own lifetime, due to the SR time dilation effect.
kevinrtrs
1.4 / 5 (7) Sep 30, 2010
Why would there be any water on this planet?
glencadia
5 / 5 (1) Sep 30, 2010
On Baby Bear, if they live under the ocean, they look up, if they can see, and there is a hazy red light coming through the water always to the east, we'll call it east, and if they swim east, it gets hotter and shallower as they go until they can't swim any futher. If they swim west, the water gets colder and colder until they run into a brick wall of ice. They could have a very advanced civilization without even knowing that there are other stars. They have never been out of the water. If they get into the atmosphere, they still couldn't see any stars because the atmosphere is not transparent.
Skeptic_Heretic
3.4 / 5 (5) Sep 30, 2010
Why would there be any water on this planet?

Why wouldn't there be, Mr. Creationist?
Quantum_Conundrum
1.9 / 5 (7) Sep 30, 2010
kevintrs:

Even though about 1/4 of the surface is probably near or above boiling temperature, about half hte surface is in total darkness.

This would cause any water to condense and freeze on the "Dark side" in polar ice caps that would spread back towards the terminator.

It is stated that the "average" temperature is believed to be between -24F and +10F, so there could be liquid water between the terminator(boundary between day and night,) and the region of 45 degrees from the terminator.

But being gravitationally locked is a big deal due to the magnetosphere issue. It means the planet's "Day" and "Year" are exactly the same length. So while the same side always faces the sun, the planet technically rotates once every 39 days just as it orbits once every 39 days. It's unlikely that any dynamo is at work in there.
Roj
5 / 5 (4) Sep 30, 2010
The new findings are based on 11 years of observations.. Given the relatively small number of stars that have been carefully monitored by planet hunters, this discovery has come surprisingly soon.
Explore the Gliese 581 system and all its planets within 20 years of real time.

We need remote telescopes orbiting between Lagrange points L2 and L3.
http://herschel.j...ge.shtml

Using interferometer telemetry, the resolving power would be equivalent to a mirror the diameter of Earths orbit, the largest distance between two mirror elements orbiting at L2 and L3.
https://secure.wi...erometry

This technology is 100 years old.
http://planetques...lson.cfm
getgoa
1 / 5 (8) Sep 30, 2010
It is frustrating that man is so unlearned in this day and age. Arcturus and the Pleiades house the earth-like planets. It is written directly in the bible and Job paid the price--where are people looking? towards Arcturus just like the bible says to do.
GSwift7
2.1 / 5 (7) Sep 30, 2010
Many of the assumptions here are only true if this is a single body. If it's a planet/moon pair, then many other possibilities arise, especially if the moon is sufficiently large. It could even mean that the planet isn't gravitationally locked with the star. A large moon should also increase the likelyhood that the planet is tectonically active.\

If the planet has plate tectonics, then there also technically wouldn't be a permanently stable "habitable zone". As continents and oceans drifted around, the hot and cold continents would change over long time scales.

Even with lots of water, the cold side glacier would not just be water ice. It would likely be water ice at the bottom, but the top would be frozen atmosphere like Mars' polar caps. With Earthlike mineralogy, CO2 could bake out of the Silicates on the hot side and condense on the cold side.

If tidally locked, then it would only be intersting to visit due to it's lack of habitabliity. It would likely be very unpleasant
ShotmanMaslo
1.2 / 5 (6) Sep 30, 2010


Atmospheric composition (if any) aside.... What about a magnetic field? Could it be a cold hunk of water/ice covered rock bathed in deadly solar radiation?


The planet has three times the mass of Earth, so it should have even hotter interior, and comparatively stronger magnetic field. But I think the presence of water could have major influence in the creation of magnetic field, so I am not sure..

Caltech_Mark
4.3 / 5 (4) Sep 30, 2010
It may be premature to assert that 581g is tidally locked. Spin-orbit tidal resonances with other planets, the presence of a satellite, and atmospheric super-rotation are all factors that could maintain an axial rotation of this planet over the eons.
Quantum_Conundrum
2.6 / 5 (5) Sep 30, 2010
The planet has three times the mass of Earth, so it should have even hotter interior, and comparatively stronger magnetic field. But I think the presence of water could have major influence in the creation of magnetic field, so I am not sure..


There are so many things we don't know about planets.

What if this thing is a "hybrid" planet and has like 1 earth mass worth of rock and metal, and 2 earth masses worth of atmosphere? Or 2 earth masses worth of rock and metal, and 1 earth mass worth of atmosphere?

In those scenarios, or anything remotely resembing them, the planet would have surface pressures of 100s or 1000s of time that of earth. Water-Ice would exist on most of the surface, while nitrogen and CO2 and other gases would still be in the atmosphere, distributing the heat.

So if it has a thick enough atmosphere, it could be at or near isothermal equlibrium, even if it is tidally locked.
GSwift7
2.5 / 5 (8) Sep 30, 2010
"The planet has three times the mass of Earth, so it should have even hotter interior, and comparatively stronger magnetic field"

That's not 100% true. From the age of the star you may be able infer the age of the planet. That will tell you a lot. If it's a young planet then it could still be molten. It could be getting frequently blasted by large meteors and comets too.

Our solar system is made of material produced in a supernova, so it's relatively high in dense mater. That dense matter contributes to Earth's interior temperature through radioactive decay. If this new planet doesn't have much radioactive material then it could be much cooler inside, despite its size.

The albedo of the planet would matter too. If the surface/atmosphere tends to reflect or absorb lots of the energy coming from its star then that would also have an effect.

As i mentioned above, the presence of a large moon would also help keep the interior hot due to tidal 'squishing' of the planet.
Gawad
5 / 5 (1) Sep 30, 2010
That's not 100% true. From the age of the star you may be able infer the age of the planet. That will tell you a lot. If it's a young planet then it could still be molten. It could be getting frequently blasted by large meteors and comets too.
All true, though Gliese 581 is estimated to be between 7 and 11 billion years old. Though at 3 earth masses the interior is probably still very much molten and convection still operating to produce a magnetic field. Also, on one hand, it's age increases the odds of life having had time to emerge there, and once that happens, well, life tends to be very tenacious. On the other hand, that also increases the odds of Gliese 581g having become tidally locked. I hope it does have a large moon or other mechanism for preventing that, otherwise, unless it has a very thick atm CO2 and then other gases could simply have frozen out on the dark side, leaving it in near vaccuum.
Quantum_Conundrum
1 / 5 (3) Sep 30, 2010
Gawad:

Assuming the planet is tidally locked:

You need high nitrogen content because nitrogen condenses to liquid at a much lower temperature than CO2 precipitates to solid.

So CO2 is good at trapping heat, but Nitrogen is better for distributing heat in a cold environment, keeping the CO2 on the dark side from freezing over. So you probably need the nitrogen content to be somewhere between 15% and 80% of the atmosphere to prevent the CO2 from becoming dry ice.

If you have not enough nitrogen, then most of the existing nitrogen would possibly become liquid on the night side, forming huge oceans of liquid nitrogen.

But if you have the right amount of nitrogen, the heat is distributed, the nitrogen never condenses. Then because the nitrogen doesn't condense, it's much harder for the CO2 to freeze for the same reason: heat from the day side would get carried to the night side faster.
Quantum_Conundrum
1 / 5 (3) Sep 30, 2010
however...

With 1.4g to 1.5g surface gravity, and a thick enough atmosphere, Nitrogen might end up liquifying at a much warmer temperature than it does at one earth atmosphere...
Gawad
not rated yet Sep 30, 2010
Q_C, I essentially agree with you. I think my statement would have been more clear written with a comma, as "...a very thick atm, CO2 and then other gases...". But I was right up against the character limit. I didn't mean to imply it needed a thick atm of C02. As you say, you don't necessarily need to trap the heat very long, just distribute it to the dark side quickly enough. Some C02 does help, though and that's the tricky thing about the gas...it traps heat well, but starts to snow out of the air at a relatively balmy -90C. Same thing with moisture...traps heat well, but once you lose it the temp starts to drop much faster (even if with it you feel more miserable at -5C than without at -20C). Anyway, I think that you've got a relatively narrow window of atmospheric make up and dynamics that makes or breaks this one for life because of likely tidal lock. Even then, if the temp doesn't stay above freezing on the dark side, virtually all the water will end up frozen there.
Thex1138
not rated yet Sep 30, 2010
Wait... How did they figure out that one side is always facing the sun??????
dtxx
1.8 / 5 (6) Sep 30, 2010
Wait... How did they figure out that one side is always facing the sun??????


They don't know that for sure.
Gawad
3.5 / 5 (2) Sep 30, 2010
Wait... How did they figure out that one side is always facing the sun??????


It's assumed, based on the distance between the star and planet. It's not certain; as other's here have pointed out, some factors such as a large moon may keep the planet from becoming tidally locked to it's star.
GSwift7
2.1 / 5 (7) Oct 01, 2010
"Wait... How did they figure out that one side is always facing the sun??????

They don't know that for sure."

Actually we are pretty sure about that. The math is well-proven and generally accepted. The only thing that may prevent it would be presence of a moon large enough and close enough to the planet so that the planet and moon are mutually tidally locked (like pluto and its moon charon).

The mechanism is actually simple. This planet is so close to its star that the gravit of the star causes a bulge on one side of the planet. That bulge is tugged by the stars gravity so that it always faces the star. Unless you have some really exotic factor to prevent it, this planet is 100% likely to be tidally locked. Wiki has a good explanation of the math. It's simple torque at its heart. There are 35 known tidally locked bodies in our solar system, including Mercury and our Moon. It's a well-understood phenomenon.
GSwift7
1.5 / 5 (6) Oct 01, 2010
Correction: I said the only thing that may prevent tidal locking is a large, close moon. A thought occured to me that MAYBE if you got enough ice accumulated on the dark side of the planet it could flip around the other way. That would be REALLY BAD NEWS for any life on that planet, if it's possible. I don't have the math muscles to figure out how much ice you would need though.
bishop
1 / 5 (3) Oct 01, 2010
Guys..., don't you remember this Australian dude that received a strong laser signal from around there, like 2 years ago ??? At that time they didn't knew about this planet "g" (only the "e" and maybe an other one, "d" or "c"?)...

http://www.realuf...rom.html

NOW, I'm VERY ex-ci-ted !!!!!!
Modernmystic
1.8 / 5 (11) Oct 01, 2010
VERY doubtful there's life here, or that if there is it's anything other than microbes.

It's tidally locked, it orbits a variable star, it probably doesn't have a magnetic field, etc etc etc.

This aint Kansas folks...sorry.
GSwift7
1.8 / 5 (5) Oct 01, 2010
Yes, Modern, it's almost certainly a horrible place, the only question is how horrible. Imagine the extremes seen on this thing. It must be like hell. Like Mercury, only with the potential of an atmosphere to make things even worse, if that's possible.
J23
4.5 / 5 (2) Oct 01, 2010
Wait, I don't understand why it wouldn't have a magnetic field if it's larger than the Earth and has more or less the same gravity?

I would imagine a core like ours could produce a magnetic field, unless the red dwarf has a low metallicity or something like that and Gliese 581 g doesn't have an iron core, though the large number of planets around the star should rule that out...can someone explain this to me?
scogostology
1 / 5 (2) Oct 02, 2010
This is just the tip of the iceberg because there are potentially more than 64 million earth-like and habitable planets in our Universe and in about another 2000 yrs, we shall discover, connect and even travel to some of them, (if we have not destroyed our world and civilization with nuclear bombs and weapons of mass destruction.) IKEY GALACTICCA, SCOGOSTOLOGY, SGSG scogostology.wordpress.com
Skeptic_Heretic
3.3 / 5 (3) Oct 02, 2010
Wait, I don't understand why it wouldn't have a magnetic field if it's larger than the Earth and has more or less the same gravity?

I would imagine a core like ours could produce a magnetic field, unless the red dwarf has a low metallicity or something like that and Gliese 581 g doesn't have an iron core, though the large number of planets around the star should rule that out...can someone explain this to me?

Well, the age of the planet comes into play here. Similar to Mars (with little to no magnetic field left) if this planet is cool cored, or worse, completely solidified, the magnetic field should be rather weak, allowing for the atmosphere to have been blown away long ago.

It's the age of the planet and what we currently understand about planetary dynamics (which is a rather small amount).
Quantum_Conundrum
1.6 / 5 (7) Oct 02, 2010
Well, the age of the planet comes into play here. Similar to Mars (with little to no magnetic field left) if this planet is cool cored, or worse, completely solidified, the magnetic field should be rather weak, allowing for the atmosphere to have been blown away long ago.

It's the age of the planet and what we currently understand about planetary dynamics (which is a rather small amount).


Let's say if it is cold cored, being 3 to 4 earth masses certainly gives it a huge advantage compared to Mars on 2 fronts.

1) Stronger gravity has got to help keep the atmosphere there anyway.

2) More mass would mean residual magnetic fields should be stronger.

Mars' mass is 0.107 earth masses, which is 28 to 37 times less massive than Gliese 381g, so the surface gravity is about 3.75 times stronger.
LuckyBrandon
2.1 / 5 (7) Oct 03, 2010
It is frustrating that man is so unlearned in this day and age. Arcturus and the Pleiades house the earth-like planets. It is written directly in the bible and Job paid the price--where are people looking? towards Arcturus just like the bible says to do.


really...even though back when the bible was originally written there was no real concept of a universe....and keep in mind, you are taking from words of a book that is HIGHLY incomplete and bastardized and was written by MAN, and what was included was also chosen by MAN.
Modernmystic
1 / 5 (8) Oct 04, 2010
A tidally locked planet probably isn't rotating very fast, this too would mean that if there is a magnetic field it's not very strong.
zbarlici
5 / 5 (1) Oct 04, 2010
It goes without saying that a lot of things play into the habitable planet scenario. Location is one of them, and they found it :)
JYK
2.3 / 5 (3) Oct 04, 2010
We should start learning how to clone scientists and make artificial wombs by freezing embryos at the 8 cell stage they should keep for the hundreds of years it would take to travel there. If the womb worked OK robots could act as teachers and nursemaids, if the planet was worth it. If not no real loss.


Oh, my! So many scifi-horror scenarios in this idea! Robo-teachers, potential for bad embryo development, disposable people (ie. "no real loss"), etc. And THEN what do they find on the other end?
mg1
3 / 5 (2) Oct 05, 2010
There are three scenarios, we find an empty planet, we meet friendly aliens and are welcomed, or we look up one day at a small micro-black hole in our atmosphere sucking away our life-blood. At least for a few hours we'd be able to say "Yes we were right there is life in our galaxy."
otto1932
5 / 5 (1) Oct 06, 2010
There are three scenarios, we find an empty planet, we meet friendly aliens and are welcomed, or we look up one day at a small micro-black hole in our atmosphere sucking away our life-blood. At least for a few hours we'd be able to say "Yes we were right there is life in our galaxy."
It wouldnt be in our atmosphere but would quickly sink to the core. And it would take a considerable length of time to do its work. Ask jigga.

Hey- where is that bottomless multicellular scamp anyways? Back in high school?

-Actually, could a MBH orbit the planet inside the atmosphere? What would we see? Would we be doused with hawking radiation every hour or so as the thing flashed by overhead?
Skeptic_Heretic
1 / 5 (1) Oct 06, 2010
Let's say if it is cold cored, being 3 to 4 earth masses certainly gives it a huge advantage compared to Mars on 2 fronts.
But on every other front it's a completely ridiculous thing to aim for. Mars is next door. If we can get there we can start building by bringing industry from Earth.

If you get to Gliese 581g what next? Nothing...
jscroft
1.8 / 5 (5) Oct 07, 2010
Anybody read Jack of Shadows, by Roger Zelazny? It's set on a tidally-locked planet, albeit with a twist...
Titto
1 / 5 (2) Oct 21, 2010
20 light years??? that means never!!!!
First proof we were on the moon........ I do not see any proof?
Modernmystic
1.4 / 5 (7) Oct 21, 2010
Hopefully this is the beginning of quieting those who believe Earth-like conditions are incredibly rare.


It might if it was something like Earth...