Near Earth-sized planet found in habitable zone: Gliese 581C

[3488]

RHM3 .<br /><br />I agree. I would doubt the existence of such a massive silicate, metal planet like a super Mercury, in orbit around this metal poor star. Thinking about it again, I wonder if this planet is a rocky / gas planet, a kind of hybrid between Earth & Uranus, an Earth sized planet with a huge, dense atmosphere & that the quoted size is far too small.<br /><br />This planet is not Earthlike & the media as usual have gone overboard. <br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[qso1]

3488:<br />This planet is not Earthlike & the media as usual have gone overboard.<br /><br />Me:<br />Agree there, and would add that the media had some help this time. I think even the scientists who discovered this are bulking the story up a bit. The fact remains, we cannot yet see these worlds which means we cannot obtain spectral data. So the only reason its reported to be earthlike is its rocky, or thought to be rocky. Its in the right orbital zone for liquid water to exist, and its only a little larger than Earth.<br /><br />On the plus side however, a little media excitement over a space related story can't be all bad considering what constitutes news nowadays. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[lost_shaman]

qso1 : <font color="yellow">I think even the scientists who discovered this are bulking the story up a bit.</font><br /><br />Well you know if you really think that and don't like the prospects for Gliese 581c, then there's always Gliese 581d! <br /><br />At 7.7 Earth masses orbiting at 0.245 AU, Gliese 581d also orbits within the outer edges of the Habitable zone and would itself be Headline News were it not for Gliese 581c taking the spotlight. <br /><br />

 

[3488]

Good point lost_shamen.<br /><br />Gliese 581 D IS an interesting object too. In fact the entire system is of interest.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[heyscottie]

But remember, if we hypothesize a larger radius, which most of us seem to agree is likely, it becomes MORE earth-like, not less, as surface gravity tends closer to g.<br /><br />The low metallicity of Gliese 581 has been noted, and I agree that it makes it somewhat harder for the system's planets to be super Mercurys. This again actually helps us, as it raises the possibility that the planets are differentiated.<br /><br />The media HAVE gone overboard in saying that the planet is earthlike, but I think we would go equally overboard in saying it is NOT earthlike.<br /><br />Too many unknowns, too many unknowns!<br />

 

[3488]

Very true heyscottie.<br /><br />This MUST be researched further. I wonder if Spitzer could help with IR spectra???<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[qzzq]

Best thing to say it is <i>most</i> Earthlike of all the planets discovered outside our system so far. <div class="Discussion_UserSignature"> <p> </p><p>***</p> </div>

 

[robnissen]

<font color="yellow">At 7.7 Earth masses orbiting at 0.245 AU, Gliese 581d also orbits within the outer edges of the Habitable zone </font><br /><br />Good point. Less likely to be tidally locked, less danger from solar flares, and if you throw in a little green-house effect, it might be downright toasty.

 

[qso1]

lost_shaman:<br />Well you know if you really think that and don't like the prospects for Gliese 581c, then there's always Gliese 581d!<br /><br />Me:<br />The prospects will improve for me when I start seeing images and spectra. Thats not to say this isn't good news...it is indeed. But its also IMO, just a transitional step to the bigger newsmakers sure to come.<br /><br />Gliese581c or d may well prove earthlike in many ways. But I suspect some future world in orbit around a star with better prospects for supporting life as we know it...will eventually be the most eartlike world yet. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

heyscottie:<br />The media HAVE gone overboard in saying that the planet is earthlike, but I think we would go equally overboard in saying it is NOT earthlike. <br /><br />Too many unknowns, too many unknowns!<br /><br />Me:<br />True. Whats needed is a sharper definition of the term earthlike. I'm not a professional astronomer but because I write about this stuff...I'm working on what could or should constitute earthlike worlds once it is better known what kind of planets we are actually looking at. This won't be possible till imaging and spectral analysis is brought to bear on these worlds. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

qzzq:<br />Best thing to say it is most Earthlike of all the planets discovered outside our system so far.<br /><br />Me:<br />Agree there, and truthfully, thats usually what is said, or something like that. But by the time the news is digested and second, third hand reported...the true thing said gets lost in translation. I have posted a couple of responses to someone who asked the very question..."How can astronomers say this planet has liquid water"? And I respond by saying they never said it had liquid water. Just that it resides in a zone where liquid water could develop. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[ctrlaltdel]

Assuming this planet is poor in metals, does this indicate a weak magnetic field? Considering 581C's proximity to it's star, even small solar flares would be damaging to life on such a world.

 

[qso1]

That brings up another question. Is Gliese 581 itself a flare star? The red dwarfs I'm familiar with are flare stars but I'm not sure about this one. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[3488]

Apaarently not. Gliese 581 is onlder red dwarf, 'only' about 400 million years younger than our own sun. Gliese 581 has settled down, unlike Proxima Centauri, which appears to be only 800 million years old!!!<br /><br />How about this APOD?<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[robnissen]

<font color="yellow">Whats needed is a sharper definition of the term earthlike.</font><br /><br />Considering how hard it has been to get an agreed definition of "planet" (See, Pluto), its probably going to be next to impossible to get an agreement on "earth-like." That being said, here is an article in Slate that tries:<br /><br />http://www.slate.com/id/2165044/<br /><br />Looking at the APOD drawing of sunrise (thx Andrew), does anyone know what the apparant magnitude of Gliese would be from this planet. My guess giving the size and closeness, it would be very high (blinding to humans?).

 

[owenander]

Definition of planet would be really easy, but just like ancient civs thought Earth should be special, people think the 8/9 large planets should be special too.<br /><br />Body orbits star = planet<br />Body orbits planet = moon<br />Other bodies like comets and asteroids can be categorized by composition and the fact they do not have sufficient gravity to "clear" their orbit.<br /><br />I'm really excited about the new planet found, at only 5x greater mass, it really isnt TOO big to be habitable. Hopefully other Earthlike characteristics are found as well.

 

[qso1]

I saw that article.<br /><br />I was working on one myself but this guy beat me to the punch. Mine goes into more detailed however. As for how hard it will be to get a definition considering the IAU and planets. I mentioned that in my piece. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[heyscottie]

Satire from "The Onion":<br /><br />http://www.theonion.com/content/amvo/earth_like_planet_discovered

 

[qso1]

heyscottie:<br />Satire from "The Onion":<br /><br />Me:<br />I liked the middle guys answer LOL. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[lampblack]

<font color="yellow">Satire from "The Onion": </font><br /><br />Well... like everyone else, the Onion missed the true significance of Gliese 581 C, as explained here. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <font color="#0000ff"><strong>Just tell the truth and let the chips fall...</strong></font> </div>

 

[dragon04]

As already stated, Gliese 581c isn't the only interesting object in the system.<br /><br />I've posted it before, but here's a link to an extrasolar planet site that lists all confirmed bodies in orbit around various stars that includes data about orbits in habitable zones.<br /><br />Most of the planets identified are Jupiter mass bodies or larger, but that doesn't preclude terrestrial and water bearing satellites that may orbit the host worlds.<br /><br />There are a lot of planets in the goldilocks zones of stars out there. While it's purely speculative, based on known satellites of Jovian planets in our own solar system, it's not a stretch of the imagination to consider Mars sized water bearing satellites in orbit around them. <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[alokmohan]

Goldilock planet is not defined.Earth like planet should be of mars and earth size.Only then we may have water in all the states ,solid,liquid and gas.And life as we know it can exist in such planets.We have to find out as it is the holy grail of astronomers.

 

[nexium]

Five times more mass does not reduce the probaility of liqiud, solid, and vapor forms of water. The liquid state will be possible at 105 c = 221 f if the surface pressure is about 2 atmospheres. The melting point of ice is independent of the pressure except above about a million atmospheres. Neil

 

[heyscottie]

lampblack: Loved the Krypton thread, especially all the shoehorning to make known "facts" about Krypton fit... I definitely agree that we should call Gliese 581c Krypton when it is formally named...

 

[lampblack]

Hey, thanks! And thus a movement begins... <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <font color="#0000ff"><strong>Just tell the truth and let the chips fall...</strong></font> </div>