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First Earth-Sized Exoplanet May Have Been Found

kdawson posted more than 5 years ago | from the but-not-as-we-know-it dept.

Space 222

Adam Korbitz writes "New Scientist is reporting the extrasolar planet MOA-2007-BLG-192Lb — whose discovery was announced just last summer — may actually be the first truly Earth-sized exoplanet to be identified. A new analysis suggests the planet weighs less than half the original estimate of 3.3 Earth masses; the new estimate pegs the planet's size at 1.4 Earth masses. The planet orbits a small red dwarf star, some 3,000 light-years from here, at an orbital distance of 0.62 astronomical units, about the same distance as Venus from our sun. One significance of the planet's discovery is that it points to the probable ubiquity of smaller terrestrial planets in somewhat Earth-like orbits around red dwarf stars, the oldest and most numerous stars in the galaxy. Here is a video report from the discoverers."

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GNAA (-1, Flamebait)

Anonymous Coward | more than 5 years ago | (#26523211)

gay nigger association of america

Re:GNAA (4, Informative)

gravos (912628) | more than 5 years ago | (#26523259)

Although this may be the first Earth-sized exoplanet, 335 exoplanets are already listed in the Extrasolar Planets Encyclopaedia. [exoplanet.eu]

Food for thought.

Re:GNAA (5, Informative)

lorelorn (869271) | more than 5 years ago | (#26523519)

Not really. The detection methods currently used to find exoplanets mean that the larger and closer the planet is to its parent star, the easier it is for us to find.

As our techniques become more sophisticated, we will be able to find more planets of a comparable size to our own. Those 335 can be thought of as the 'first wave' of discovered exoplanets. Large bodies close to their parent stars. These planets are interesting for what they can tell us about how solar systems can form.

The next wave of discovered exoplanets will be smaller, say between the sizes of Venus and Neptune, and therefore far more interesting from the perspective of extrasolar life.

Earth-sized != Earth-like (5, Interesting)

Anonymous Coward | more than 5 years ago | (#26523547)

Just because it's an earth-sized planet doesn't mean it's Earth-like. Red dwarf stars are very small (no more than half the mass of the Sun). They don't put out much energy so the habitable zones are very small and very close to the planet. Being so close to the sun makes it likely that the planet would be tidally locked (same side always facing the sun) which isn't so good for life. Finally red dwarf stars often have high stellar variation (sometimes fry you, sometimes freeze you), also not so good for life.

So exciting, but keep looking.....

http://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems

Re:Earth-sized != Earth-like (0)

Anonymous Coward | more than 5 years ago | (#26524633)

Sure, but being Earth-sized is a fucking prerequisite to being Earth-like, which means that for the first time there's a *chance* it's Earth-like, as you admit by your use of the words "likely" and "often" instead of "certain" and "always".

Re:Earth-sized != Earth-like (2, Funny)

binarylarry (1338699) | more than 5 years ago | (#26524899)

Don't give me any of that 'Star Trek' crap. It's too early in the morning.

Bloody smeg head.

Re:GNAA (4, Funny)

Nimey (114278) | more than 5 years ago | (#26523711)

This must be the first Slashdot post with a GNAA subject line that's been modded "informative" in years.

Re:GNAA (-1, Offtopic)

Ethanol-fueled (1125189) | more than 5 years ago | (#26523457)

Anybody want to pitch in? [slashdot.org]

Re:GNAA (0)

Anonymous Coward | more than 5 years ago | (#26523493)

That's the lamest GNAA post yet. Come on, not even the "Are you gay..." line. It's like you're not even trying.

Believe it or not, I met a GNAA member in Kuwait. Really, we were trading Iraq stories outside of the NLC Villa and I told her how I got my job through posting on /. She then revealed her "secret identity", but I think she's cool since she told my Country Manager that she hoped he'd die in a mortar attack.

Quick (0, Flamebait)

mfh (56) | more than 5 years ago | (#26523265)

Pack up all the religious nuts and MAN THE COLONY SHIP!

Re:Quick (0)

CorSci81 (1007499) | more than 5 years ago | (#26523295)

Don't forget the telephone sanitizers.

Re:Quick (0, Troll)

Anonymous Coward | more than 5 years ago | (#26523387)

Holy shit dude, that means sending off basically the entire Slashdot population! Who'll be left here to talk about Linux and Open Sores and Darwinism and Gloomal Warbling etc.?

When can I pack my bags? (4, Funny)

erroneus (253617) | more than 5 years ago | (#26523269)

I'm all about getting the hell out of here!

Ummm (1)

EmbeddedJanitor (597831) | more than 5 years ago | (#26523571)

Earth might be broken in some ways, but it is (most likely) a lot better environment than anything else out there. Earth is a far better starting position than Mars or whatever and fixing what's broken here would be far more achievable than trying to build a viable human-sustaining ecosystem on some other planet.

On the flip side... (5, Insightful)

interactive_civilian (205158) | more than 5 years ago | (#26523679)

Earth might be broken in some ways, but it is (most likely) a lot better environment than anything else out there. Earth is a far better starting position than Mars or whatever and fixing what's broken here would be far more achievable than trying to build a viable human-sustaining ecosystem on some other planet.

On the flip side, the spin-off technologies from making a sustainable habitat off planet would probably do wonders for improving the quality of life on planet. Everything from medical technology to air scrubbing and environmental cleanup, food and nutrition to understanding of local ecology and balancing it, energy technology to waste disposal and recycling, and probably much more.

Re:On the flip side... (1, Interesting)

Anonymous Coward | more than 5 years ago | (#26524801)

No need for any new technologies. Just stop fucking with the existing systems, wind the population down to 10m and enjoy. This is Eden and to not get that is very sad. The very concept of "it needs improving" is why we are so fucked today. See http://www.kansascity.com/news/world/story/986910.html

Re:Ummm (1, Interesting)

jo42 (227475) | more than 5 years ago | (#26524389)

The problem isn't Earth - its humanity. And if we do get out there, we'll break that too.

Re:Ummm (1)

DigiShaman (671371) | more than 5 years ago | (#26524709)

Life's a bitch, aint it?

Re:Ummm (3, Interesting)

ppanon (16583) | more than 5 years ago | (#26524931)

Not necessarily. The problem is the "unthinking" masses of humanity. We have it really easy on Earth compared to the artificial environments that we would need to sustain ourselves in space. First we'll have to figure out a long-term approach for how to reliably protect our reproductive organs from ambient high-energy radiation once away from the Earth's magnetic field so that independent colonies don't get overwhelmed by birth defects. Eventually though, living in space would apply a whole new set of evolutionary pressures for survival and human space-farers would have to adapt. If we survive long enough to permanently colonize space, it would probably transform that part of humanity that would make it into space by making it much more aware of risk evaluation and risk taking, and general incompetence will get weeded out fairly quickly and ruthlessly by the ambient dangers of space.

It might take a few failed colonies at first, but eventually a society would evolve a way to ensure that happens. Perhaps mandatory civil service that involves external colony maintenance as a requirement for political office? Or maybe even the same for obtaining the voting franchise - a sort of Starship Troopers lite.

In fact, if you were a space-going race you probably wouldn't want to establish contact with a species that hadn't already gone through that winnowing out process. I would even go so far as to say that that difference might eventually lead to true divergence of humans into two species: the earth-bound and the space-faring.

If "we" get out there, the people that colonize another planet probably won't be the same "people" that are messing up Earth right now because those people wouldn't survive long enough to make it that far. Yeah, it's kind of an elitist view, but evolution is the ultimate meritocracy and, in very harsh environments, the people that forget that don't stay in the gene pool long.

Re:Ummm (4, Funny)

Nefarious Wheel (628136) | more than 5 years ago | (#26524623)

I want to live in a garden and have the universe as my toy, spinning at my whim and containing all my dreams, pets and machines. I want green, sunlit gardens and waterfalls with Waldos stepping through the murk and smoke of sunless moons, digging my wealth. I want iced tea, fast machines, flying cars and friendship that never dies. And I want another planet to study. Yes, another planet.

But the doctor says I can't have iced tea. He said nothing about the rest.

Re:Ummm (5, Insightful)

PTBarnum (233319) | more than 5 years ago | (#26524733)

I anticipate that someday science will advance to the point where ordering up your own private garden planet, and a fleet of intelligent and loyal robots to tend it for you, is considered routine. A wormhole network connecting your plant to a set of resource-rich sunless moons will be included at no extra charge.

Everyone will have eternal life and health, lots of friends, and be allowed by their doctors to drink all the ice tea they want.

But we still won't have flying cars.

Re:When can I pack my bags? (2, Insightful)

azakem (924479) | more than 5 years ago | (#26523605)

You should probably pack now and get moving, I hear it's kind of a long flight.

Re:When can I pack my bags? (2, Funny)

erroneus (253617) | more than 5 years ago | (#26523673)

Not as bad as you think... I hope to achieve near light speed within the first twenty-four hours. In your time, I am not entirely sure what that will be, but the question is moot as you may be pretty close to dead by then...and your kids...

Re:When can I pack my bags? (5, Insightful)

fractalspace (1241106) | more than 5 years ago | (#26523709)

Remember what we see is a 3000 year old image of the planet. It may not even exist today.

Re:When can I pack my bags? (3, Funny)

erroneus (253617) | more than 5 years ago | (#26523753)

You're like a kid with a pin and a balloon. You just had to ruin it didncha?

Re:When can I pack my bags? (0)

Anonymous Coward | more than 5 years ago | (#26523761)

Remember what we see is a 3000 year old image of the planet. It may not even exist today.

Its more likely that when you get there you'll find chavs have moved in next door and property prices will be shit.

or the previous tennant left the light on and you'll be hit with a 3000 year old electricity bill.

Re:When can I pack my bags? (3, Interesting)

biocute (936687) | more than 5 years ago | (#26524347)

This got me thinking:

If inhabitants there invented faster-than-light space travel, and arrived on Earth thousands of years ago. Eventually their civilization was destroyed by some freak natural disasters and all techs were lost.

We are just their descendants, now looking at our home planet?

Re:When can I pack my bags? (1)

Neo Quietus (1102313) | more than 5 years ago | (#26525069)

Hey, were you watching the news yesterday?

"Two months ago, a satellite detected an object under the sands of the Sahara Desert.
An expedition was sent.
An ancient starship, buried in the sand. Deep inside the ruin was a single stone that will change the course of our history forever.
On the stone was etched a galactic map and a single word more ancient than the clans themselves:
Hiigara.
Our home."

Re:When can I pack my bags? (0)

Anonymous Coward | more than 5 years ago | (#26524419)

Does this mean we should start eyeing up teenage planets?

Re:When can I pack my bags? (1)

fyoder (857358) | more than 5 years ago | (#26524467)

Remember what we see is a 3000 year old image of the planet. It may not even exist today.

Or it might, but it's no longer ruled by space pharaohs.

Re:When can I pack my bags? (4, Funny)

Petrushka (815171) | more than 5 years ago | (#26524573)

Remember what we see is a 3000 year old image of the planet. It may not even exist today.

It's not clear to me what "today" should mean in this context. Presumably there's a frame of reference in which Earth today and this other planet 3000 years ago are simultaneous ...

... er, come to think of it, that frame of reference would be ... here, wouldn't it?

Re:When can I pack my bags? (3, Interesting)

sleeponthemic (1253494) | more than 5 years ago | (#26524015)

Make sure you put velcro on your tool bag - they've been known to float away.

Re:When can I pack my bags? (1, Interesting)

jamesh (87723) | more than 5 years ago | (#26524263)

3000 light years means that we are seeing it as it was 3000 years ago. If you could get to the speed of light right now, it would be 3000 years until you got there (assuming that the relative distance between us is roughly constant). But you can't go that fast, you'd have to go a lot slower than that.

In the next 3000 years we are sure to develop much faster methods of travel, so will will overtake you (i'll wave as we pass) and when you get there all the hot alien babes will be taken.

announcement (0)

Anonymous Coward | more than 5 years ago | (#26523301)

Pluto got robbed, man!

ps June 2, 2008 (4, Informative)

MRe_nl (306212) | more than 5 years ago | (#26523313)

Using standard nomenclature, the star hosting the newly discovered planet is dubbed MOA-2007-BLG-192L with MOA indicating the observatory, 2007 designating the year the microlensing event occurred, BLG standing for bulge, 192 indicating the 192nd microlensing observation by MOA in that year and the L indicating the lens star as opposed to the background star further in the distance. The planet maintains the name but adds a letter designating it as an additional object in the star's solar system, so it is called MOA-2007-BLG-192Lb.

Hello MOA-2007-BLG-192Lb. How are you? We're fine thank you.
How's the weather? Would you like to play a game?

Re:ps June 2, 2008 (1)

davolfman (1245316) | more than 5 years ago | (#26524073)

Does this remind anyone else of the system for naming planets in Stargate?

Re:ps June 2, 2008 (1)

Tacvek (948259) | more than 5 years ago | (#26524493)

I'll meet you on P3X-834, to discuss this similarity in naming systems.

Re:ps June 2, 2008 (-1, Offtopic)

Anonymous Coward | more than 5 years ago | (#26524267)

MOA-2007-BLG-192Lb

But it's friends just call it "Dennis".

might be a lil off topic (3, Informative)

ani23 (899493) | more than 5 years ago | (#26523323)

but how do /.'ers figure out which is the actual link to the article. Case in point this one. there are 5 different links which go to 5 different places. is there one link whihc goes to the actual article or is it just a mashup of information?

Re:might be a lil off topic (0)

Anonymous Coward | more than 5 years ago | (#26523663)

It should be made obvious which link leads where by the wording of the summary. It's just reading an article on wikipedia actually.
Admittedly, sometimes it's a little confusing. Not this time though, imo.

Re:might be a lil off topic (3, Insightful)

Silicon Jedi (878120) | more than 5 years ago | (#26524163)

You really must be new here. Slashdotters don't RTFA.

Well... (3, Interesting)

actionbastard (1206160) | more than 5 years ago | (#26523327)

MOA-2007-BLG-192Lb ain't LV-426. If you know what I mean...

Re:Well... (1)

john.picard (1440397) | more than 5 years ago | (#26523577)

It's like that movie where the thing came out of his stomach and killed all the people on the fuckin' spaceship, God rest their souls.

Re:Well... (1)

Daniel Dvorkin (106857) | more than 5 years ago | (#26523775)

You won't know that for sure unless you set down there on Company orders. My advice? Don't.

Smeg me... (1)

theshowmecanuck (703852) | more than 5 years ago | (#26524731)

I don't care as long as they got good curry!

'Earth-sized' can be misleading (4, Insightful)

Vandil X (636030) | more than 5 years ago | (#26523371)

I know the use of the term 'Earth-sized' brings more views, but hopefully the non-science/tech people out there reading it will realize that that is just a physical comparison and not a suggestion that life is present.

e.g. Venus is also 'Earth-sized' but is highly inhabitable (for life as we know it)

Re:'Earth-sized' can be misleading (3, Funny)

Vandil X (636030) | more than 5 years ago | (#26523375)

doh. highly uninhabitable.

Re:'Earth-sized' can be misleading (2, Informative)

morgan_greywolf (835522) | more than 5 years ago | (#26523681)

Downright inhospitable, in fact, which is -- I think -- the word you were looking for.

Re:'Earth-sized' can be misleading (1)

ceoyoyo (59147) | more than 5 years ago | (#26523819)

What term would you suggest?

Earth-like is a fuzzy phrase that gets used sometimes when someone wants to generate some hype. Earth-sized is pretty specific. Any undue excitement is entirely the fault of the reader.

A Venus type orbit around a red dwarf is probably pretty chilly.

Re:'Earth-sized' can be misleading (1)

GradiusCVK (1017360) | more than 5 years ago | (#26524279)

Uninhabitable. See also inflammable.

Re:'Earth-sized' can be misleading (0, Offtopic)

GradiusCVK (1017360) | more than 5 years ago | (#26524313)

Sorry, didn't see you already caught this. Where's that delete comment button...

Re:'Earth-sized' can be misleading (0)

Anonymous Coward | more than 5 years ago | (#26524507)

And the Venusians are quite proud of this fact.

Re:'Earth-sized' can be misleading (0)

Anonymous Coward | more than 5 years ago | (#26524979)

Well, duh. It's in orbit around a red sun, so clearly it must be Krypton-like - not Earth like.

I wouldn't exactly hold my breath for Kryptonian overlords to welcome though (but just in case, Hail Zod!).

Darkover (1)

dokhebi (89124) | more than 5 years ago | (#26523399)

Maybe it's Cottman IV. Do you think the Chierie are there waiting for us?

Just my $0.02 worth...

Re:Darkover (1)

Daniel Dvorkin (106857) | more than 5 years ago | (#26523481)

It sounds like it's cold enough! Stock up on rabbithorn fur.

Re:Darkover (1)

weetabeex (1065032) | more than 5 years ago | (#26524153)

How much is that in euros these days?

Settle Venus and Mars first. (2, Interesting)

john.picard (1440397) | more than 5 years ago | (#26523533)

Why don't we figure out how inhabit to Venus and Mars first, and then look for things farther away? At 3000 light years, it's a bit too far to think of starting a settlement there.

Re:Settle Venus and Mars first. (0)

Anonymous Coward | more than 5 years ago | (#26523801)

I think the point of looking for Earth-sized planets outside of our solar system is looking for the possibility of extraterrestrial life, not looking for a place to build our condos...

Re:Settle Venus and Mars first. (1)

morgan_greywolf (835522) | more than 5 years ago | (#26523941)

I think the point of looking for Earth-sized planets outside of our solar system is looking for the possibility of extraterrestrial life, not looking for a place to build our condos...

But we can do that on our own planet. In fact, just hang out here long enough. You're sure to find some.

Re:Settle Venus and Mars first. (1)

John Hasler (414242) | more than 5 years ago | (#26524063)

> Why don't we figure out how inhabit to Venus and Mars first...

Go right ahead. No one is stopping you.

> ...and then look for things farther away?

Because that is what some people want to do? You needn't look if it bothers you.

> At 3000 light years, it's a bit too far to think of starting a settlement there.

I wasn't aware that anyone was doing so.

Re:Settle Venus and Mars first. (3, Interesting)

burning-toast (925667) | more than 5 years ago | (#26524635)

Venus will never be a good candidate for habitation unless we build platforms which "float" on its atmosphere's surface due to the close proximity to the sun. Wikipedia has some decent overview here: http://en.wikipedia.org/wiki/Colonization_of_Venus [wikipedia.org]

Mars is also quite small and does not hold onto its atmosphere very well (which coincidentally means it also doesn't have a strong magnetic field of it's own in which to protect potential inhabitants from solar radiation amongst other things (again due to its size)), so colonizing it will only really be possible if we build sealed enclosures on its surface or find a way to generate a LOT of atmosphere over a long time AND we find a way to protect our self from radiation from space in a feasible manner.

I am not an educated member in these related fields, but this is the information I have picked up while taking a passing interest in this stuff.

On top of that, finding other planets which are earth like does not have to happen in an either / or situation with attempting to colonize other planets. Both research paths can and are being pursued at the same time because it takes an entirely different scientist and research field to find extra-planetary bodies than it will to find a way to terraform one.

- Toast

Re:Settle Venus and Mars first. (1)

theshowmecanuck (703852) | more than 5 years ago | (#26524797)

I didn't see anything in that Wikipedia article talking about magnetic fields. I would think it would be more important for a planet closer to the sun than earth (i.e. Venus) to have a strong magnetic field to protect us weak Earthlings from the stronger solar radiation that Venus would have to have (being closer to the sun and all). I think that particular article is more wishful thinking than anything else (gasp!!! on Wikipedia???). ;)

Re:Settle Venus and Mars first. (1)

burning-toast (925667) | more than 5 years ago | (#26525133)

Epic fail. As stated in my post the magnetic field issue pertains to Mars due to its small size, not Venus.

Transforming another planet in our solar system into something habitable is wishful thinking in it's entirety at this point. OTOH, simply finding other planets is something we can already do, we just need to refine the techniques and technology.

As far as terraforming goes we have been met with moderate failure just trying to build a self contained biosphere on planet earth (which we know to be an inhabitable body for fact): http://en.wikipedia.org/wiki/Biosphere_2 [wikipedia.org]

- Toast

Re:Settle Venus and Mars first. (1)

burning-toast (925667) | more than 5 years ago | (#26525191)

Also, objects such as Jupiter, Saturn, and the rest of the Milky Way Galaxy let off enormous amounts of radiation. You can read more about problems encountered by the Galileo probes for Jupiter: http://en.wikipedia.org/wiki/Galileo_(spacecraft)#Other_radiation_related_anomalies [wikipedia.org]

And other sources about radiation on Mars:
http://www.space.com/spacenews/archive07/undergroundmars_0205.html [space.com]

http://www.lip.pt/events/2006/ecrs/proc/ecrs06-s0-141.pdf [www.lip.pt]

http://www.voanews.com/english/archive/2003-03/a-2003-03-14-11-Mars.cfm [voanews.com]

Turns out.. (0)

Anonymous Coward | more than 5 years ago | (#26523551)

The cylons have already been there.

So? (5, Interesting)

bradbury (33372) | more than 5 years ago | (#26523559)

If you are familiar with the work of Charlie Lineweaver's group in AU, you would be aware that not only should Earth-like planets exist but that a significant number of them are older, and potentially more advanced than we are. This might then lead you to explore whether or not Matrioshka Brains (forms of civilizations significantly more advanced that our own exist.) And indirectly to an understanding that extremely advanced stellar civilizations have very different heat signatures (or detection signatures) from our own. Thus the detection of an earth-like planet is not that significant. The detection of a star going dark, signaling a civilization making a Kardashev-Type-I to a Kardashev-Type-II transition -- now that would be interesting.

Re:So? (5, Interesting)

osu-neko (2604) | more than 5 years ago | (#26523793)

If you are familiar with the work of Charlie Lineweaver's group in AU, you would be aware that not only should Earth-like planets exist but that a significant number of them are older, and potentially more advanced than we are.

Familiarity with Lineweaver's work does not make one "aware" of that "fact", it merely makes one aware that some people have argued that that is the case. :p

Lineweaver, Davis, and such have proposed a number of ideas which are intriguing, but it's all on very tiny and shaky foundations. Not saying they're wrong, but if they're reasonably close to right, that's more luck than anything, given the sample size of there real data it's all based on (e.g. estimating how many Earth-like planets develop life in their first billion years based on the one and only example we have of it happening).

Re:So? (1)

ramul (1103299) | more than 5 years ago | (#26524435)

And how come they haven't detected us and come to say hello if they are so advanced? If they do exist we can conclude that they are quite rude.

Re:So? (2, Insightful)

burning-toast (925667) | more than 5 years ago | (#26524701)

Along that same line of logic: How come we haven't found them and said "Hi!"? I would suggest that problems we face may not be terribly different from problems other potential civilizations have come across (should they exist).

I'm sure there are plenty more issues we have yet to discover with long-range communications through space. Let alone the process of finding other intelligent beings to communicate with or finding an intelligible way to communicate between two entirely different species... Don't let the dreamed up solutions from Sci-Fi movies make you think there are easy or even possible solutions to those problems.

Ever try and carry on a conversation with a dolphin for example? How about over thousands of light-years worth of space?

- Toast

Re:So? (4, Funny)

Anonymous Coward | more than 5 years ago | (#26523803)

If you are familiar with the work of L. Ron Hubbard's group in OT8, you would be aware that not only should Earth-like planets exist but that a significant number of them are older, and potentially more advanced than we are. This might then lead you to explore whether or not the Marcab Confederacy (form of civilization significantly more advanced that our own exist.) And indirectly to an understanding that extremely advanced stellar civilizations have very different Body Thetans (or Operating Thetans) from our own. Thus the detection of an earth-like planet is not that significant. The detection of a star going dark, signaling a civilization making an R5-Implants to an R6-Implants transition -- now that would be interesting.

Re:So? (1)

QuantumG (50515) | more than 5 years ago | (#26523973)

Or collecting solar power is considered so primitive to an "advanced" civilization that your prediction that stars are going to blink out from them building solar collectors around them is just naive.

Re:So? (0)

Anonymous Coward | more than 5 years ago | (#26524289)

Or collecting solar power is considered so primitive to an "advanced" civilization that your prediction that stars are going to blink out from them building solar collectors around them is just naive.

Also, blinking out would bring the berserkers for sure!

Re:So? (2, Funny)

sleeponthemic (1253494) | more than 5 years ago | (#26523977)

you would be aware that not only should Earth-like planets exist but that a significant number of them are older

Haha, foolish human. Everybody knows that Earth holds the record for the oldest planet at a 6000 years.

Re:So? (-1, Troll)

Anonymous Coward | more than 5 years ago | (#26524717)

will you just shut the fuck up? do you have to spread your hate everywhere you go?

how about shoving a hot poker up your ass? i would find that amusing. bitch.

Re:So? (3, Funny)

sleeponthemic (1253494) | more than 5 years ago | (#26524853)

Irony

Re:So? (2, Informative)

ceoyoyo (59147) | more than 5 years ago | (#26523983)

For those who like to see some actual observations back up speculation, detection of an Earth-sized planet is a big deal. Until we see some, we can't really say how many such planets exist. Once we see one we know that we can detect them. Once we see two, we can start to make (poor) estimates of how many there are. From there the estimates only get better.

I'm sure Dr. Lineweaver would agree, see as how the first research interest listed on his web page is "the analysis of recent exoplanet data and its ability to address the question 'Is our Solary System typical?'" (http://www.mso.anu.edu.au/~charley/)

Re:So? (0)

Anonymous Coward | more than 5 years ago | (#26524875)

Evey Hammond: Are you like a crazy person?

Re:So? (1)

0xdeadbeef (28836) | more than 5 years ago | (#26525021)

If civilizations are that common, then the threat of attack by competing civilizations is more pronounced, therefore survivors will go to great lengths to hide themselves.
We should assume that our simple technology will never detect a Type-II civilization because they would never announce their presence so obviously as by enclosing a star.

Quick quiz (5, Interesting)

The Bungi (221687) | more than 5 years ago | (#26523581)

Since the strength of the gravitational field of a planet is a factor of its mass, and the gravitational pull on the surface is in direct relation to the distance from the center of the planet... could it not be possible to have a planet the size of say, Neptune, with a geological makeup similar to the Earth, that has a lower mass and therefore the acceleration at the surface is exactly 1g (as we understand it here on Earth). That is within the bounds of physics, is it not?

Or maybe the effective gravity is stronger, but the planet spins faster. Faster days as well?

The problem I guess would be the existence of a formation process that actually creates a planet with such a large surface but happens to be mostly rock instead of mostly gas (supposedly gas giants are "failed stars"). If it has a molten iron core, would it not collapse in on itself?

Interesting, imagine a planet with the surface composition and atmosphere of Earth (and supposedly biomass) but 10 or more times the surface. That would be amazing.

Re:Quick quiz (1)

cdrguru (88047) | more than 5 years ago | (#26523807)

You are missing something.

If a planet has a geological makeup like Earth but is 10x the size, then it will have 10x the mass have a surface gravity 10x that of Earth.

A gaseous planet 10x the size of Earth might well have a surface gravity (such as it is?) that of Earth as it might be about the same mass.

Either way, I wouldn't like to go there. A planet with a 10G gravitational constant wouldn't be my idea of a good time, although it might be fun to stand off a ways and see what was going on there. A long ways - I'm allergic to anything much over 1.5G. A mini-gas giant wouldn't be very interesting at all.

Re:Quick quiz (1)

The Bungi (221687) | more than 5 years ago | (#26523951)

No, but you're missing my point. Of course if you take Earth and make it 10x larger then it will have 10x the mass, and therefore you'll experience 10x the acceleration at surface level, assuming no variations in rotational speed (acceleration in the opposite direction). That will be hard on your joints, to say the least.

What I'm theorizing about is a planet whose geological structure makes it have *less* mass, and therefore generate the same gravitational field as Earth (1g), while at the same time increasing the effective surface by the same amount of relative size. Not mass.

Perhaps it's a planet where the majority of the crust is some sort of very strong honeycomb-like structure, maybe more lightweight material (like pumice?) with a smaller iron core or something like that.

Re:Quick quiz (3, Informative)

Anonymous Coward | more than 5 years ago | (#26524461)

It would have to be composed of dramatically different mix of elements; low density due to structural differences would not be possible beyond some fairly small radius -- far, far, smaller than Earth. Basically, once an object is large enough that gravity can form the object in to a sphere, the mass of the object will be high enough to obliterate any pore space beyond a fairly shallow depth. The details can be fairly readily calculated knowing the strength of rock, which is indeed well known for rock types that would constitute the bulk of any likely Earth-size planet.

The likelihood of maintaining a structurally low density planet, beneath a very shallow layer at the top of the planet's crust, is further reduced due to the problem of heat. Rock weakens as heat increases, and heat increases with depth. Even a geologically dead planet would have or have had considerable heat at depth at some point in its life, at which time the low density material would have collapsed.

This also ignores how such a body could form, certainly beyond my creativity to imagine.

A planet simply is not going to be low density by virtue of its structure. You need different materials.

The bulk of the Earth is made of silicate rock, iron, and nickel, giving it an average density of about 5.5 grams per cubic centimeter. You could build a planet of somewhat lower density using various kinds of ice.

The problem there, however, is that you probably won't be able to achieve density much lower than something between 1.2 and 1.8 grams per cubic centimeter (the precise amount depends on how exotic a composition you're willing to invent and its total mass -- substances will possess increasingly dense crystal structures as the material is put under higher pressure). That's a lot less than Earth, but not close to the level's originally suggested. And this planet certainly isn't going to look an awful lot like Earth. It'll look more like Titan.

Re:Quick quiz (2, Informative)

ceoyoyo (59147) | more than 5 years ago | (#26524007)

A planet with the same composition as Earth but with 10 times the mass will NOT have 10 times the surface gravity. It's radius will be larger, so the surface gravity will be less than 10x, but greater than 1x.

Re:Quick quiz (1, Interesting)

Anonymous Coward | more than 5 years ago | (#26524199)

If the density is the same as Earth, then 10x the radius is 1000x the volume and hence 1000x the mass.

Gravity goes like GM/(r^2) so the increase radius partially cancels the increase in mass but not completely.

In the end, gravity is 10x stronger.

(Posting as AC because already started moderating ...)

Re:Quick quiz (3, Informative)

Daniel Dvorkin (106857) | more than 5 years ago | (#26523865)

could it not be possible to have a planet the size of say, Neptune, with a geological makeup similar to the Earth, that has a lower mass and therefore the acceleration at the surface is exactly 1g

It's entirely possible for a gas giant -- according to Wiki, the "surface gravity" of Neptune is 1.14g, and for Uranus it's 0.886g. I put "surface gravity" in quotes here for obvious reasons, but something like the "cloud city" in The Empire Strikes Back would be quite livable on either of these planets. As for rocky planets, it seems doubtful. Anything solid that was of Neptunian size and mass would, I think, very quickly collapse into a much more compact mass with much higher surface gravity.

Re:Quick quiz (3, Insightful)

samkass (174571) | more than 5 years ago | (#26524319)

according to Wiki, the "surface gravity" of Neptune is 1.14g, and for Uranus it's 0.886g. I put "surface gravity" in quotes here for obvious reasons, but something like the "cloud city" in The Empire Strikes Back would be quite livable on either of these planets.

Assuming, of course, that you don't mind being crushed to pulp, or have some way of surviving 1000mph windstorms. Of course, for energy you'd have all the natural gas you could ever wish for, if only there were some oxygen around to burn it with.

Re:Quick quiz (2)

Daniel Dvorkin (106857) | more than 5 years ago | (#26524485)

Crushed to a pulp? "Surface" pressure on Neptune is 1 bar, same as Earth. For power, if you have controlled fusion there's no lack of hydrogen ... Weather might be a problem, although if you stay high enough you should be able to avoid the worst of it, and float with the rest.

Re:Quick quiz (1)

ceoyoyo (59147) | more than 5 years ago | (#26523883)

Sure. Neptune itself has a surface gravitational acceleration of exactly 1g, if you define "surface" creatively enough.

If you want a solid surface, you're probably aiming a little high with something Neptune-sized. You could postulate a planet made entirely out of less dense materials, with very few metals and such, but realistic solid planet building materials don't have a really huge density range.

You can have surprisingly massive planets of terrestrial-like composition with surprisingly low surface acceleration because they have larger diameters though.

Re:Quick quiz (1)

kzieli (1355557) | more than 5 years ago | (#26523897)

Not really feasible. Saturn has a gravitational pull of 0.92G and Neptune has 1.14G and both of them have ended up as gas planets. The real killer for humans would the the atmospheric pressure, not the gravity. Jupiter is the only planet where the gravitational pull is significantly greater then on earth 2.36g. Volume increase much faster then surface area. so you need to reduced the density to match, otherwise your surface gravity goes up. push this too far and you don't have enough left to make a solid surface that can maintain structural integrity, or hold up heavy things like oceans. The interesting thing which isn't present in our solar system is a world that is predominantly made of liquid. I believe some nineteenth century astronomers thought that Neptune was such a world.

Re:Quick quiz (1)

Fluffeh (1273756) | more than 5 years ago | (#26524121)

that can maintain structural integrity, or hold up heavy things like oceans.

that can maintain structural integrity, or let light things like oceans float to the surface - there fixed that for you.

Re:Quick quiz (0)

Anonymous Coward | more than 5 years ago | (#26523943)

Surface gravity is proportional to radius * average_density, so if you take the Earth and multiply its radius by x and divide its density by x, then you still get 1.0 g at the surface.

Anyone else... (1)

McCat (1438893) | more than 5 years ago | (#26523751)

immediately think of Asimov's "Nemesis" novel when they read this article?

Re:Anyone else... (1)

Nimey (114278) | more than 5 years ago | (#26523871)

no.

3000 LY (0)

Anonymous Coward | more than 5 years ago | (#26523957)

As if there weren't enough stars below 25ly ... someone donate a better telescope plz !!!

ronpaul? (0, Offtopic)

tdwMighty (1453161) | more than 5 years ago | (#26523979)

Why is ronpaul a tag? Is he an exoplanet? I never knew that!

Re:ronpaul? (0, Offtopic)

Carbon016 (1129067) | more than 5 years ago | (#26524759)

He is a little out there.

As warm as Pluto or as cold as Venus... (2, Informative)

xristoph (1169159) | more than 5 years ago | (#26524101)

Or the other way round, of course ;) From TFA:

The planet orbits its host star at a distance equivalent to that of Venus from our Sun. Because the host star is probably between 3000 and 1 million times fainter than our Sun, the top of the planet's atmosphere is likely colder than Pluto. However, planetary formation theory suggests a thick atmosphere blankets the planet, which combined with radioactive decay in the planet's interior may make it as warm as Earth.

So it could be inhabitable, it might have an ocean, and maybe there are aliens that look like E.T. living there. Maybe. But does it have a Stargate?

Sized? (2, Interesting)

nog_lorp (896553) | more than 5 years ago | (#26524173)

I'm used to size meaning volume...

Otherwise you might say a bullet is the size of 100 feathers...

who cares about the discoverers? (2, Interesting)

Gothmolly (148874) | more than 5 years ago | (#26524283)

I want to see video of the planet.

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