More Earthlike planets out there than thought?


Creative Writer
An interesting read calculating that Earthlike planets may be out there in numbers far greater than thought. Of course colonisation might need to follow converting planets to habitable conditions. But the fact that there is already life on planets means that those planets are more easily transformed.

Last Updated: Sunday, 17 February 2008, 21:51 GMT

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'Hundreds of worlds' in Milky Way

By Helen Briggs
Science reporter, BBC News, Boston

Scientists say there may be many more worlds in our solar system

Rocky planets, possibly with conditions suitable for life, may be more common than previously thought in our Solar System, a study has found.

New evidence suggests more than half the Sun-like stars in the Milky Way could have similar planetary systems.
There may also be hundreds of rocky worlds undiscovered in the outer part of our galaxy, astronomers believe.
Future studies of such worlds will radically alter our understanding of how planets are formed, they say.
New findings about planets were presented at the American Association for the Advancement of Science (AAAS) in Boston.
Nasa telescope
Michael Meyer, an astronomer from the University of Arizona, said he believes Earth-like planets are probably very common around Sun-like stars.
I expect that we will find a very large number of planets

Alan Stern

"Our observations suggest that between 20% and 60% of Sun-like stars have evidence for the formation of rocky planets not unlike the processes we think led to planet Earth," he said.
"That is very exciting."
Mr Meyer's team used the US space agency's Spitzer space telescope to look at groups of stars with masses similar to the Sun.
They detected discs of cosmic dust around stars in some of the youngest groups surveyed.
The dust is believed to be a by-product of rocky debris colliding and merging to form planets.
Nasa's Kepler mission to search for Earth-sized and smaller planets, due to be launched next year, is expected to reveal more clues about these distant undiscovered worlds.
Frozen worlds
Some astronomers believe there may be hundreds of small rocky bodies in the outer edges of our own Solar System, and perhaps even a handful of frozen Earth-sized worlds.
We have to find the right mass planet and it has to be at the right distance from the star

Debra Fischer
San Francisco State University

Speaking at the AAAS, Nasa's Alan Stern said he believes we have found only the tip of the iceberg in terms of planets within our own Solar System.
More than a thousand objects had already been discovered in the Kuiper belt alone, he said, many rivalling the planet Pluto in size.
"Our old view, that the Solar System had nine planets will be supplanted by a view that there are hundreds if not thousands of planets in our Solar System," he told BBC News.
He believes many of these planets will be icy, some will be rocky, and there may even be objects the same mass as Earth.
"It could be that there are objects of Earth mass in the oort cloud (a cloud surrounding our planetary system) but they would be frozen at these distances," Mr Stern added.
"They would look like a frozen Earth."
Goldilocks zone
Excitement about finding other Earth-like planets is driven by the idea that some might contain life or perhaps, centuries from now, allow human colonies to be set up on them.
The key to this search, said Debra Fischer of San Francisco State University, California, was the Goldilocks zone.
This refers to an area of space in which a planet is just the right distance from its parent star so that its surface is not-too-hot or not-too-cold to support liquid water.
"To my mind there are two things we have to go after; we have to find the right mass planet and it has to be at the right distance from the star," she said.
The AAAS meeting concludes on Monday.


Avoid A Void
interesting story tim. i agree that there has to be at least one habitable planet out there somewhere. still i feel that our scientist think in one dimension so-to-speak. "the planet has to be the right distance from the sun". that may be so for us but not for another civilization. it could be possible that other life forms and intelligent ones at that require something else.

i think gene roddenberry had it correct by creating life that wasnt totally similar to us. vulcans lived on a hot, humid world. klingons on a dark, dank world. the gorn, reptiles with intelligence. etc, etc.

the point is we dont know what to expect and we need to broaden our prespective of what could be out there. it will make it easier to find and accept when we do find it or they find us.


Creative Writer
I don't think it is intelligent life they are talking about, but any life, that suggests the planet is terraformable to within human range of living.


Avoid A Void
i understand. i guess when i was talking about being one sided i should have thought of myself also. i realize now i live in that same perspective as others, that life has to be more than an amoeba.

i would welcome the discovery of a world that could be habitable to us


Creative Writer
The argument against though is that the expense and mineral resource depletion to send people out won't be productive, since it will deplete the Earths resources, plunge us into economic recession.

Their aren't many pluses I can see to colonising attempts.

One is that if there is other intelligence out there, the very physical act of colonisation will get us noticed, or eligible to join their club. But that is a risk considering the economic problems of getting a small colony crew out there.

A second could be the discovery of new minerals/elements that could provide new forms of safe energy for us. If a few elements enter our periodic table, returning those elements could be worth the expense.