Possible Earth-like planet discovered

Houston Comical (AP) ^ | June 13, 2005, 2:14PM

[The_Victor]

WASHINGTON  — A planet that may be Earth-like — but too hot for life as we know it — has been discovered orbiting a nearby star.

The discovery of the planet, with an estimated radius about twice that of Earth, was announced today at the National Science Foundation.

"This is the smallest extrasolar planet yet detected and the first of a new class of rocky terrestrial planets," Paul Butler of the Carnegie Institution in Washington said in a statement. "It's like Earth's bigger cousin."

Geoffrey Marcy, professor of astronomy at the University of California, Berkeley, added: "Over 2,000 years ago, the Greek philosophers Aristotle and Epicurus argued about whether there were other Earth-like planets. Now, for the first time, we have evidence for a rocky planet around a normal star."

Though the researchers have no direct proof that the new planet is rocky, its mass means it is not a giant gas planet like Jupiter, they said. They estimated the planet's mass as 5.9 to 7.5 times that of Earth.

It is orbiting a star called Gliese 876, 15 light years from Earth, with an orbit time of just 1.94 Earth days. They estimated the surface temperature on the new planet at between 400 degrees and 750 degrees Fahrenheit.

Gliese 876 is a small, red star with about one-third the mass of the sun. The researchers said this is the smallest star around which planets have been discovered. In addition to the newly found planet the star has two large gas planets around it.

Butler said the researchers think that the most probable composition of the planet is similar to inner planets of this solar system — a nickel/iron rock.

Gregory Laughlin of the Lick Observatory at the University of California, Santa Cruz, said a planet of this mass could have enough gravity to hold onto an atmosphere. "It would still be considered a rocky planet, probably with an iron core and a silicon mantle. It could even have a dense steamy water layer."

Three other extrasolar planets believed to be of rocky composition have been reported, but they orbit a pulsar — the flashing corpse of an exploded star — rather than a normal type of star.

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On the Net:

National Science Foundation: http://www.nsf.gov

[IllumiNaughtyByNature]

Good point. I will be interested to see what the astro-propeller heads here tell us. :o)

[inquest]

No, it looks right to me. The earth orbits at 93 million miles. If this thing has a longer orbital period than the earth, then it would be orbiting farther out than us if it were in our solar system. While it's true that its sun is less massive than ours (2/3 less massive), that difference in mass is not enough to bring the orbital radius down from about 150 million miles (which is about where Mars is at, with a period of 1.88 years) to 2 million miles.

[IllumiNaughtyByNature]

1.88 years

doesn't the original post say days?

[mikrofon]

What is the mathematical formulae for gravity?

G^mn = -(8pG/c²)T^mn
ds² = c²(1-2MG/c²r)dt² - dr²/(1-2MG/c²r) - r²(dq²+sin²qdf²).
dt = (1-2MG/c²r)^1/2dt
dt1/dt2 = (1-2MG/c²r1)^1/2/(1-2MG/c²r2)^1/2
rc = 2MG/c²
dt1/dt2 = (1-MG/c²R)(1+MG/c²(R+h)) =  1 - (MG/c²)[1/R - 1/(R+h)]
1-dt1/dt2 = (MG/c²)(h/R²)
(n2-n1)/n2 = (MG/c²)(h/R²)

[IllumiNaughtyByNature]

Here is what is throwing me off.

with an orbit time of just 1.94 Earth days

Is this a revolution on its own axis or around its sun?

[airborne]

A planet that may be Earth-like — but too hot for life as we know it —

Well then, it isn't earth-like, is it?

[null and void]

A rocky world that size [Jovian] (an impossibility)

I'll bite. Why is this impossible?

[inquest]

The 1.88 years is for Mars. 1.94 days is for Gliese, and it does refer to the orbit time around its sun, not its rotation on its axis (which I don't think they're even able to measure at this point).

I brought up Mars to give a comparison to what it would be like if this planet had an orbital period of 1.94 years, so as to show why 1.94 years is unlikely.

[Redcloak]

"It's hot, Jim."

[cookcounty]

If Earth-like, then for sure it has well-developed life on it.

Any evolutionist (or would they prefer to be called "abiogenesists?) can tell you that.

[Euro-American Scum]

Looks like global warming affected this planet....

And this, too, is Bush's fault.

[IllumiNaughtyByNature]

Thanks for the info.

[Huntress]

Hehehe

[Drammach]

Earth-like, in the context of this article, refers to an inner planet, not being a gas giant, but being a "rocky" planet, with a nickel iron core, similar to earth..

Mars is also an earth-like planet, although half the size and 1/10th the gravity, and a CO2 atmosphere..
Likewise, Venus is an earth-like planet, having a nickel iron core equal to earth, being equal in mass and size, but having a dense CO2 atmosphere, and being much too close to the sun, resulting in extremely high planetary temperature..

[Eaker]

Iron-cored planet ping!!

[Mon]

ping to self

[Junior]

From what I understand, it's impossible for a rocky planet that big to form. That's why all the really big planets are gas giants.

[null and void]

Hmmm. I wonder why? I can understand there being a size limit to a gas giant, (When it gets big enough, it's not a planet, it's a star!) but I don't see a limit to how many rocks you could pile in one place?

[pax_et_bonum]

Aluminum.

You said so yourself.

Molten aluminum.

[Eaker]

LOL!!

I think you had one too many Corona beers!!