Planet Gliese 581g may not exist.

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3488

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Remember Gliese 581g, the Earth-like planet whose discovery scientists announced two weeks back, saying it could potentially sustain life? Bad news: Not only were the initial reports that “the chances for life on this planet are 100 percent” overblown; now, new data suggests that the planet may not actually exist.

Steven Vogt, the researcher who led the team that announced the Gliese 581g discovery (and the utterer of the now-infamous “chances for life on this planet are 100 percent” line, which he cla..............

Article here.

I suspect the vast majority of extrasolar planets detected by this method, may now be in doubt & the number of 'confirmed' extrasolar planets will now fall sharply. I expect though once better imaging techniques are in place, James Webb Telescope is launched & on station, KEPLER has been observing longer, etc, they will start rising once again. The very few imaged directly like Fomalhaut b, H788 a,b,c, Beta Pictoris b, etc do physically exist for sure as well as those that have passed the transiting method (three consecutive observed transits across their parent stars).

This is a bitter disappointment for sure, perhaps Gliese 581g does exist, but we cannot be sure now, in fact the others thought to be orbiting the red dwarf star Gliese 581 may not really exist either as they were 'detected' the same way.

Perhaps the Peer Review process really needs to be tightened up. It gives science a very bad name, mistakes happen, that's part of being human, but wild speculation & hyperbole, of which Gliese 581g was a great example, does not do science any favours.

Also the wild speculation & hyperbole about supposed subsurface oceans on Europa & Enceladus needs to stop, until we have more direct concrete information.

Andrew Brown.
 
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Couerl

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We all knew this was one of those too good to be true stories. What bugs me though, aside from the overblown hype is the idea that even the Webb won't be all that great of a planet hunter.
 
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Gravity_Ray

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Well I hope they continue to work this issue out at Gliese, and that knowledge should also be helpful at other stars. Unfortunately as long as there is a media that is ready to over hype anything, its to be expected for some media hype.

Dont want to go off topic, but Gliese is one thing, but determining the existence of oceans on Europa and Enceladus really should be moved up on the "to-do" list. Instead of some silly mission to a NEO these two moons should be looked at with more detail. Finding an extra-Earth ocean will be just as much of big news as an Earth like planet at Gliese.

An ocean in our own solar system is a greater find than an Earth like planet a few tens of light years away. That can be hyped as much as they want.
 
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MeteorWayne

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Well, there's nothing intrinsically wrong with the technique.

However, as with all scientific data and analysis, one must exercise plenty of care so as to not announce discoveries before they are robust enough to stand up to scrutiny. Dismissing the existance of the planet before all the evidence has been examined would be just as irresponsible as announcing it too early.

Let the scientific process take it's course.
 
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kg

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The article posted doesn't say what method they were using. Were they detecting transits, radial velocity or some other method? What went wrong?
 
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MeteorWayne

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Radial velocity.

Radial velocity is tricky, you have to ensure that a whole bunch of effects are properly cancelled out... the earth's orbital motion and rotation, tidal effects from the moon, relative motion between the two systems, etc, etc...

Like I said, let the scientific process play out before judging...
 
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rocketmonkey

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As I said in the article, I don't take this with much significance. The laws of mathematics, estimation, and probability say that there are 10000000000000000000000 habitable planets in the universe today. :ugeek: One that is 20.5 light years away is not that crazy.

And every scientific discovery has doubt. :roll: ;) :cool:
 
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kelvinzero

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rocketmonkey":3qmgrbhz said:
As I said in the article, I don't take this with much significance. The laws of mathematics, estimation, and probability say that there are 10000000000000000000000 habitable planets in the universe today. :ugeek: One that is 20.5 light years away is not that crazy.

And every scientific discovery has doubt. :roll: ;) :cool:
Thats another thing that I think people don't get, especially the ones urging us to send an interstellar probe right away.

The methods tend to rely on fortuitous alignments of the planet's orbits wrt to us, tiny orbits around the stars, and other such features. Just because scientists think they may have discovered this world 20 ly away does not mean they do not expect to find even better and closer candidates shortly. There must be a lot of stars in a 20 LY radius.. 100 stars? 1000?

One thing I would be interested to know is how many habitable-zone planets the scientific community expects should exist within twenty LY, based on the number we have discovered and the luck involved in discovering each one.
 
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MeteorWayne

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I should point out that Gliese 581 f and g have never been officially accepted as extrasolar planets, and have never shown up in the Extrasolar Planets Encyclopedia...

http://exoplanet.eu/catalog-RV.php

They are on this list; the "unconfirmed, contoversial, or retracted" list:

http://exoplanet.eu/catalog-contro.php

The current status is:

"Planet detections published in papers submitted to professional journals (S)"
 
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robnissen

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kelvinzero":1wrwta05 said:
There must be a lot of stars in a 20 LY radius.. 100 stars? 1000?
Not thousands. There are about 111 stars within 80 star systems within 20 LY of earth.
 
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kk434

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Radial velocity method only gives a lower mass estimate, does that mean that the 3 earth masses is the lowest possible weight for this planet and if Gliese system is not edge on the planet can be much larger than 3 earth masses?
(If this planet exists)
 
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MeteorWayne

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That's correct. There's really not enough evidence one way or the other.
 
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EarthlingX

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SDC : Astronomer Stands By Discovery of Alien Planet Gliese 581g Amid Doubts
By Mike Wall
SPACE.com Senior Writer
posted: 13 October 2010
02:55 pm ET

Despite the doubts raised recently over the existence of the potentially habitable alien world Gliese 581g, the planet's co-discoverer is standing behind his find.

Steven Vogt, leader of the team that detected Gliese 581g, said he respects the work of the researchers who questioned the planet's existence yesterday (Oct. 12). He said he cannot comment on the scientists' results, since he hasn't seen their data.

But he has confidence in his own team's conclusions.

"I stand by our data and analysis," Vogt, an astronomer at the University of California, Santa Cruz, said in an e-mail interview with SPACE.com. "I feel confident that we have accurately and honestly reported our uncertainties and done a thorough and responsible job extracting what information this data set has to offer. I feel confident that anyone independently analyzing this data set will come to the same conclusions."

Vogt added that he looks forward to reading the other team's results when they're published in a peer-reviewed journal. He's not necessarily expecting Gliese 581g to be yanked off the list of extrasolar planets, though.

"In 15 years of exoplanet hunting, with over hundreds of planets detected by our team, we have yet to publish a single false claim, retraction or erratum," Vogt said. "We are doing our level best to keep it that way."
...
 
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emperor_of_localgroup

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Since the beginning of finding exoplanets, I have been taking all news of exoplanets with a question mark.

I'll totally get into exoplanets only when they show us an optical picture, which doesn't look like another star. Artist's renderings do not cut with me.

What if the stars with so called exoplanets are really failed pulsars? Orbital fluctuations of the stars (center of star's orbit) can be caused by so many factors.

Astronomer's (in fact, true for most scientists) minds work with this motto, IMHO, if it fits one theory, ignore all other possibilities.
 
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