My Pet Peeve About Commonality of Earth-Like Planets

[Airbrush]

If Earth-like planets were very common, we would have detected a lot of them already from the Kepler Mission.

 

Kepler is watching about 150,000 stars, the vast majority of which are smaller than the Sun. This means the Goldilocks Zone for these smaller stars is closer to the star than in our solar system. This means they should have seen more planets with periods of shorter than one year. They are waiting until they see 3 transits before confirming a planet. There has been plenty of time already to have seen habitable planets around smaller stars, and we haven't seen them.

 

They jump to a wild conclusion that there are 50 Billion planets in our galaxy and if only 1% of these are Earth-like, than there must be half a Billion Earth-like planets in our galaxy. Who is interested in Earth-like planets farther away than about a thousand light years? I am only interested in LOCAL Earth-like planets, that we could possibly travel to in the next few thousand years.

 

Let me know if you feel my exasperation.

Edited September 18, 2012 by Airbrush

[Moontanman]

If Earth-like planets were very common, we would have detected a lot of them already from the Kepler Mission.

 

Kepler is watching about 150,000 stars, the vast majority of which are smaller than the Sun. This means the Goldilocks Zone for these smaller stars is closer to the star than in our solar system. This means they should have seen more planets with periods of shorter than one year. They are waiting until they see 3 transits before confirming a planet. There has been plenty of time already to have seen habitable planets around smaller stars, and we haven't seen them.

 

They jump to a wild conclusion that there are 50 Billion planets in our galaxy and if only 1% of these are Earth-like, than there must be half a Billion Earth-like planets in our galaxy. Who is interested in Earth-like planets farther away than about a thousand light years? I am only interested in LOCAL Earth-like planets, that we could possibly travel to in the next few thousand years.

 

Let me know if you feel my exasperation.

 

You do realize that a transiting planet is dependent on the plane of the planets orbit crossing the star from the stand point of the earth. Very few stars/planets are so aligned so we would not expect to see very many planets in this situation. I'm not sure of how many such planets have been found but if for instance we see 10% of all stars are aligned so their planets do transit from our perspective and we see that 1% of those do have a planet in the correct zone it would indicate a rather high percentage of planets in the "life" zone. To make a judgement call on this you would have to be able to plug in real numbers to the values. But since few stars/planets are visible this way I don't expect to see many "earth like" planets via this method close to the earth.

[Airbrush]

You do realize that a transiting planet is dependent on the plane of the planets orbit crossing the star from the stand point of the earth. Very few stars/planets are so aligned so we would not expect to see very many planets in this situation. I'm not sure of how many such planets have been found but if for instance we see 10% of all stars are aligned so their planets do transit from our perspective and we see that 1% of those do have a planet in the correct zone it would indicate a rather high percentage of planets in the "life" zone. To make a judgement call on this you would have to be able to plug in real numbers to the values. But since few stars/planets are visible this way I don't expect to see many "earth like" planets via this method close to the earth.

 

Yes, we will see transits in only about 0.5% of stars with planets. Later they will extrapolate that whatever transits they detect, the actual number is about 200 times what they can see.

 

But the recent news I heard is they were seeing more small planets than larger ones. This would lead one to suppose there are very many Earth-sized planets. Yet, I was watching "How the Universe Works" on the Science Channel, and they said the closest thing they can find to Earth-like is the 4th planet out from Gliese, which is twice Earth's size. It's been over 3 years since the mission began. So why don't they see more smaller planets? Maybe the program is based on data only about 2 years old?

[Moontanman]

Yes, we will see transits in only about 0.5% of stars with planets. Later they will extrapolate that whatever transits they detect, the actual number is about 200 times what they can see.

 

But the recent news I heard is they were seeing more small planets than larger ones. This would lead one to suppose there are very many Earth-sized planets. Yet, I was watching "How the Universe Works" on the Science Channel, and they said the closest thing they can find to Earth-like is the 4th planet out from Gliese, which is twice Earth's size. It's been over 3 years since the mission began. So why don't they see more smaller planets? Maybe the program is based on data only about 2 years old?

 

 

It's a possibility that the show was out of date, I haven't seen anything about how the mission is going since the Gliese planets were announced either.