Second Earth' Possibly Discovered

[anoopsaxena76]

Apparently with a smaller star, the effect of gravity and heating would be less and with no satellite found so far and assuming presence of water bodies on the planet, tides would be absent or negligible. Add to it the 37 day 'solar year', and one face of the rock in perpetual darkness. With an atmosphere, assuming like ours, that would be some weather.

Okay some of the points that immediately come to my mind.

1.) Since it is in a habitable zone, one would expect the temperature to be more or less closer to the one, we have on earth.

2.) The smaller the star, the slower the star burns out, so it means a longer life. What we do not know, or at least I do not know (scientists may have figured out), is which state the star is in?

3.) The distance between the star and the planet itself has to be taken into account.

4.) I think you confused the word weather with "perpetual day" on one side. Weather is due to the inclination on one's axis. That is why my original question.

5.) Does it have a moon? I think we couldn't be sure as yet. There is no way we can detect such a small body so far away. Besides, tides can be generated by the stars itself, depending on the orbit of the planet.

Regards,
Anoop

 

[Zeluvaa]

Okay some of the points that immediately come to my mind.

1.) Since it is in a habitable zone, one would expect the temperature to be more or less closer to the one, we have on earth.

2.) The smaller the star, the slower the star burns out, so it means a longer life. What we do not know, or at least I do not know (scientists may have figured out), is which state the star is in?

3.) The distance between the star and the planet itself has to be taken into account.

4.) I think you confused the word weather with "perpetual day" on one side. Weather is due to the inclination on one's axis. That is why my original question.

5.) Does it have a moon? I think we couldn't be sure as yet. There is no way we can detect such a small body so far away. Besides, tides can be generated by the stars itself, depending on the orbit of the planet.

Regards,
Anoop

1) Mean temperature scientists are predicting are from 0-40 degree Celsius. Overall temperature taking into effect greenhouse effect will be colder than Earth.

2)The star is a red dwarf roughly 7-11 billion years old. And since it is only a third of Sun's mass, it is expected to last billions of years more than the Sun.

3) The planet is most likely tidally locked with the star. Thus there would not be any axial tilt and thus no seasons in conventional sense.

Since the planet is tidally locked, one side will be in perpetual darkness hence much more colder than the side constantly facing the star - which would be much hotter. However the in between zone would have perfect temperatures.

Interestingly A Message From Earth (AFME) was sent to another one of Gliese 581's planet called Gliese 581c in 2008 using a radio telescope. There were 501 messages selected from Bebo website through competition. It will reach the planet in 2029.

Perhaps we can send one to Gliese 581g now.

 

[anoopsaxena76]

1) Mean temperature scientists are predicting are from 0-40 degree Celsius. Overall temperature taking into effect greenhouse effect will be colder than Earth.

Yes but that is taking into accounts many predictions. Besides, let's say the temperature is off by 20 degrees towards colder side, even then life can exist.

I guess you also mean the same.

2)The star is a red dwarf roughly 7-11 billion years old. And since it is only a third of Sun's mass, it is expected to last billions of years more than the Sun.

3) The planet is most likely tidally locked with the star. Thus there would not be any axial tilt and thus no seasons in conventional sense.

Agreed, those were my points too.

Regards,
Anoop.

 

[Developereo]

according to it both T4 and predators r hit

Predators came in at #31 worldwide -- maybe not a total flop, but certainly not a hit. And not in the same class as most Arnold movies.

1) Mean temperature scientists are predicting are from 0-40 degree Celsius. Overall temperature taking into effect greenhouse effect will be colder than Earth.

How can we make these predictions with knowing the atmospheric composition? Is the atmosphere more like Venus or Earth?

2)The star is a red dwarf roughly 7-11 billion years old. And since it is only a third of Sun's mass, it is expected to last billions of years more than the Sun.

Life on Earth remained primitive for three billion years; it is only in the last 500 million years that diversity kicked in. So huge geological timespans are not necessarily needed for complex life to evolve.

3) The planet is most likely tidally locked with the star. Thus there would not be any axial tilt and thus no seasons in conventional sense.

Since the planet is tidally locked, one side will be in perpetual darkness hence much more colder than the side constantly facing the star - which would be much hotter. However the in between zone would have perfect temperatures.

Not necessarily. The extreme temperature differences could just as easily fuel perpetual monster storms in the temperate zones. It is hard to imagine complex, let alone intelligent, life evolving without at least some stability.

On the plus side, we have been proven wrong so many times on life's adaptability on Earth itself, so it's possible life can evolve in extreme circumstances. The bad news is that such extremeophiles always tend to be primitive.

So, bottom line, we may find primitive life on other planets but it won't be a significant discovery. Nobody is going to get excitged about an extra-terrestrial amoeba. Most non-scientists will quicky shrug it off and life will go on as usual. It is only the discovery of intelligent life, though not necessarily technologically advanced, that will change human society.

 

[Zeluvaa]

How can we make these predictions with knowing the atmospheric composition? Is the atmosphere more like Venus or Earth?

I do not know how they made the predictions. Current technology does not allow us to determine atmospheric or surface temperatures for the planet due to the star. But I guess they may have made a prediction on the basis of the planet's distance from the star and the star'e energy output.

Life on Earth remained primitive for three billion years; it is only in the last 500 million years that diversity kicked in. So huge geological timespans are not necessarily needed for complex life to evolve.

One of the advantage of being around a red dwarf is that it gives a lot of time for life to begin and hang around. Even though it took complex life 500 million years, it still took more than 3.5 billion years from the start regardless.

Not necessarily. The extreme temperature differences could just as easily fuel perpetual monster storms in the temperate zones. It is hard to imagine complex, let alone intelligent, life evolving without at least some stability.

On the plus side, we have been proven wrong so many times on life's adaptability on Earth itself, so it's possible life can evolve in extreme circumstances. The bad news is that such extremeophiles always tend to be primitive.

Life may evolve and be sustained in the oceans at that planet, even if surface climate is erratic and dangerous. Regardless, we do not know much about the planet and right now all we have is mostly speculation.

So, bottom line, we may find primitive life on other planets but it won't be a significant discovery. Nobody is going to get excitged about an extra-terrestrial amoeba. Most non-scientists will quicky shrug it off and life will go on as usual. It is only the discovery of intelligent life, though not necessarily technologically advanced, that will change human society.

I disagree. If we manage to find life, even in primitive form, outside of Earth, that would be a shattering, history changing event. It will break the perception that Humans are unique, that we are special, alone.

It will be a humbling moment for Humans, as it will prove that we may just be one of many beings and life in the universe. It will pose an even bigger dilemma for religions and their teachings.

 

[Safriz]

Looking at how badly we are abusing the planet we already got,i wont be supporting Human race to exploit another planet.

 

[Developereo]

I do not know how they made the predictions. Current technology does not allow us to determine atmospheric or surface temperatures for the planet due to the star. But I guess they may have made a prediction on the basis of the planet's distance from the star and the star'e energy output.

I understand they used spectroscopic analysis of the star's light filtering through the planet's atmosphere to get some idea of its atmospheric composition. But I don't know how complete a picture it gave.

One of the advantage of being around a red dwarf is that it gives a lot of time for life to begin and hang around. Even though it took complex life 500 million years, it still took more than 3.5 billion years from the start regardless.

My point was that it is not the span of time that matters, but some other factor. Life here stayed essentially stagnant for 3 billion years. Then something happened and all of a sudden, evolution kicked off in full gear. We don't know what that something was. Would it happen everywhere regardless, or was it a chance coincidence having to do with the right sized satellite, or Jupiter, or some interstellar cloud that the Solar system happened to pass through?

We just don't know.

If we manage to find life, even in primitive form, outside of Earth, that would be a shattering, history changing event. It will break the perception that Humans are unique, that we are special, alone.

It will be a humbling moment for Humans, as it will prove that we may just be one of many beings and life in the universe. It will pose an even bigger dilemma for religions and their teachings.

I am not so sure about that. I agree that the discovery of the first extra-terrestrial amoeba will be huge news. But if we find nothing more complex, the excitement will die down in the general public. If we keep finding more and more planets with nothing more complex than amoebas, we will be back to square one: humans being unique in the universe.

 

[Chogy]

Is there life outside the earth? I am sure there is.

The problem, though, is the developmental level of that life. I suspect that for every planet with beings on it that have developed radio, there might be 10,000 that will never get beyond bacteria, mold, and algae. And while these might be exciting to scientists, I would guess they will be carbon-based and not dissimilar from what we have.

When people hear "life", I think too many expect intelligence/sentience. They think E.T. or grays, and I think these may end up being incredibly rare.

If we could magically transport to this planet, we might find some algae or cyanobacterial mats in the grey zone, but the odds of finding cities of sentient beings, probably not high.

 

[anoopsaxena76]

I understand they used spectroscopic analysis of the star's light filtering through the planet's atmosphere to get some idea of its atmospheric composition. But I don't know how complete a picture it gave.

In my opinion, no. By doing spectroscopic analysis, with current technology, one can only predict the existence of a planet. Not it's composition.

My point was that it is not the span of time that matters, but some other factor. Life here stayed essentially stagnant for 3 billion years. Then something happened and all of a sudden, evolution kicked off in full gear. We don't know what that something was. Would it happen everywhere regardless, or was it a chance coincidence having to do with the right sized satellite, or Jupiter, or some interstellar cloud that the Solar system happened to pass through?

We just don't know.

I disagree here. With the interstellar gases forming, sun, the earth and the other planets, it took time for Earth to be what it is today. These geographical processes do take that amount of time. For the basic single cell organic life to evolve, the conditions had to first get right.

I am not so sure about that. I agree that the discovery of the first extra-terrestrial amoeba will be huge news. But if we find nothing more complex, the excitement will die down in the general public. If we keep finding more and more planets with nothing more complex than amoebas, we will be back to square one: humans being unique in the universe.

Not sure. The curiosity of a human is not satiable. The discovery opens up a host of avenues like.
a.) Can we settle there in the future, say a million years from now. At least before the Sun explodes?
b.) Can we guarantee that not finding a more complex / intelligent life means it does not exist? It could also mean, that we need better science to figure things out.
c.) A renewed energy to look out for more such planets and build better equipments to observe the planet in discussion.

Regards,
Anoop.

 

[Developereo]

In my opinion, no. By doing spectroscopic analysis, with current technology, one can only predict the existence of a planet. Not it's composition.

Actually, spectrocopic analysis is used precisely to determine gaseous composition. Here's how it works.

We first take readings of the star's light and determine its spectroscopic signature. Then, as the planet starts to pass in front of the star, the star's light has to pass through the planet's atmosphere and certain frequencies get absorbed by gases in the atmosphere. When we compare this spectroscopic signature with the earlier one, we can tell which elements are present in the planet's atmosphere.

I disagree here. With the interstellar gases forming, sun, the earth and the other planets, it took time for Earth to be what it is today. These geographical processes do take that amount of time. For the basic single cell organic life to evolve, the conditions had to first get right.

No, that's the whole point. Life on Earth formed very very early on, almost 3.5 billion years ago. But it stayed single cellular for 3 billion years. Something happened 500 million years ago to kick start evolution and the question is how common that something would be.

If it's a rare event, then we wil find lots and lots of extraterrestrial amoebas, but nothing more interesting. If it's common, then the universe may be teeming with complex life.

 

[Zeluvaa]

Actually, spectrocopic analysis is used precisely to determine gaseous composition. Here's how it works.

We first take readings of the star's light and determine its spectroscopic signature. Then, as the planet starts to pass in front of the star, the star's light has to pass through the planet's atmosphere and certain frequencies get absorbed by gases in the atmosphere. When we compare this spectroscopic signature with the earlier one, we can tell which elements are present in the planet's atmosphere.

Currently there has been no analysis of Gliese 581 g's atmosphere. I have read many researchers say that the stars glare is too much for us to find out atmospheric composition with current equipments.

No, that's the whole point. Life on Earth formed very very early on, almost 3.5 billion years ago. But it stayed single cellular for 3 billion years. Something happened 500 million years ago to kick start evolution and the question is how common that something would be.

If it's a rare event, then we wil find lots and lots of extraterrestrial amoebas, but nothing more interesting. If it's common, then the universe may be teeming with complex life.

I guess you are talking about the Cambrian Explosion.

Many theories have been given for this explosion ranging from change in level of oxygen, snowball earth, mass extinction, etc. Some recent evidences have revealed that the explosion may not have been that big. That there might have been "appearances" of animals before the explosion.

 

[gubbi]

Currently there has been no analysis of Gliese 581 g's atmosphere. I have read many researchers say that the stars glare is too much for us to find out atmospheric composition with current equipments.

Not yet. But may be people are trying those experiments.

@ Anoopsaxena: Developereo has nicely explained why the weather there might be quite a phenomena, assuming (like I previously said) that the rock indeed has an atmosphere and huge water bodies.

@ Developereo: Excellent explanations. Couldnt have put it better.

 

[FSLN]

If it's true,then pack your bags guys,we are leaving this pro-war planet.

only afew people in the USA and mabe Russia will be able to leave, they will leave us to rot here...

 

[anoopsaxena76]

Actually, spectrocopic analysis is used precisely to determine gaseous composition. Here's how it works.

We first take readings of the star's light and determine its spectroscopic signature. Then, as the planet starts to pass in front of the star, the star's light has to pass through the planet's atmosphere and certain frequencies get absorbed by gases in the atmosphere. When we compare this spectroscopic signature with the earlier one, we can tell which elements are present in the planet's atmosphere.

I could be wrong here, but my point was that, currently we do not have technology to study an exoplanet that way. Our spectroscopic analysis is limited to planets in our solar system and stars.

As I said, I can be wrong, so I will try to find out more on this and will get back.

No, that's the whole point. Life on Earth formed very very early on, almost 3.5 billion years ago. But it stayed single cellular for 3 billion years. Something happened 500 million years ago to kick start evolution and the question is how common that something would be.

If it's a rare event, then we wil find lots and lots of extraterrestrial amoebas, but nothing more interesting. If it's common, then the universe may be teeming with complex life.

Ahh okay I see what you mean. True, we are dealing with many unknowns over there.

 

[anoopsaxena76]

Nevertheless, we estimate the equilibrium temperature given L⋆ = 0.0135L⊙ for the
host star. We assume a Bond albedo for the planet of A=0.3, a typical value for objects in
the inner Solar System (Earth’s Bond albedo is 0.29). For the 36.6-day planet candidate,
its semi-major axis of 0.146 AU leads to an equilibrium temperature of 228 K. If instead the
Bond albedo is assumed to be 0.5, the equilibrium temperature becomes 209 K. This planet
candidate would thus appear to also satisfy another necessary condition for habitability,
that Teq < 270 K.
An equally important consideration is the actual surface temperature Ts. The
equilibrium temperature of the Earth is 255 K, well-below the freezing point of water, but
because of its atmosphere, the greenhouse effect warms the surface to a globally-averaged
mean value of Ts = 288 K. If, for simplicity, we assume a greenhouse effect for GJ 581g
that is as effective as that on Earth, the surface temperatures should be a factor 288/255
times higher than the equilibrium temperature. With this assumption, in the absence of
tidal heating sources, the average surface temperatures on GJ 581g would be 236 – 258 K.
Alternatively, if we assume that an Earth-like greenhouse effect would simply raise the
equilibrium temperature by 33 K, similar to Earth’s greenhouse, the surface temperature
would still be about the same, 242 – 261 K.

This is from the paper by the lead scientist of the group which discovered the planet.

The paper is available for free and hence I quoted from it. I do not know how to attach it here though for everyone's easy reference.

Anyway, the important points to note are that the temperature and composition is speculated about and while going through some astronomy groups, the general belief was that currently our spectroscopic analysis is not advanced enough to study exoplanets' atmosphere. The above text seems to point that too.

But then again, I could be wrong. Will try to ask a scientist, but that will take weeks.

Regards,
Anoop