
US scientists find potentially habitable planet near Earth - DanielBMarkham
http://news.yahoo.com/s/afp/20100929/sc_afp/usastronomyplanet_20100929210707
======
avar
Phil Plait just posted a writeup about this:
[http://blogs.discovermagazine.com/badastronomy/2010/09/29/po...](http://blogs.discovermagazine.com/badastronomy/2010/09/29/possible-
earthlike-planet-found-in-the-goldilocks-zone-of-a-nearby-star/)

~~~
hartror
His write up is far more suitable for the HN audience, has plenty of science,
grains of salt and uses the very scientific word "probably" a lot (that isn't
a joke).

~~~
BrandonM
_His write up is far more suitable for the HN audience, has plenty of science,
grains of salt and uses the very scientific word "probably" a lot (that isn't
a joke)._

I agree. I submitted the link fully expecting that it would simply vote up
someone else's submission, but apparently it hadn't been submitted yet. Now it
has been: <http://news.ycombinator.com/item?id=1742200>

------
dbrannan
Voyager 2 (man's fastest space craft) is traveling 35,000 miles per hour / 60
= 583 miles per second.

187,000 miles per second equals the speed of light.

Light can travel 57,395,520,000,000 miles in one year (roughly 5.7 trillion
miles).

So, in 21 years that would equal 57,395,520,000,000 miles x 21 years, or
roughly 120 trillion miles.

Thus, if Voyager 2 was our space craft we'd have 583 miles per second x 60
seconds x 60 minutes x 24 hours x 365 days x 21 years to get 386,095,248,000
billion miles towards our new planet.

There is a huge gap between 386 billion and 120 trillion miles, like 311
times.

That means it would take us roughly 310 x 21 years = 6528 years to get there
using current technology.

I just don't see us going there as being very practical.

\--------

EDIT: I'm getting down voted for doing the math! Seriously?

~~~
mfukar
Wow. I'd never thought I'd see Voyager 2 being cited as the state-of-the-art.

~~~
sgt
We just need to put our heads together and create a warp drive. Come on
people, let's do it. It must be possible! "Warp drive by 2030" - next Obama
speech.

------
olegkikin
The fastest space craft we have (twin Helios probes) travels at 250 000 km/h

(20 light years) / (250 000 km/h) = 86,340 years

~~~
brc
That was my first thought. Sounds close but is unimaginably far away. I keep
flipping back to the difficulties for stone-age man to cross the english
channel, and the exponential speed of technological progress, and yet I still
can't see it happening for a long, long time. But 100 years ago we couldn't
fly the length of a football field, now we do it as a matter of routine.

Thus my mind is a flip-flopping mess of 'can't be done', 'you never know',
'can't be done'... you ge the picture.

Then I start worrying about technological progress being lost through
war/politics/religion and having a library of Alexandria moment and having to
start all over again.

~~~
russell
English Channel: until about 9000 years ago you could walk across. Stone age
people had boats too.No historical analogy can come close to interstellar
distances.

~~~
brc
Fine ; Atlantic Ocean to stone age man. In hindsight, sure, boat development
was coming along and it was only a matter of time. But you take the average
stone age man, and tell him that you can sail (or fly) across the ocean one
day to another land - that's the sort of leap of faith we require now to
believe in interstellar travel. Sure the distances are bigger than any
analogy, but distances are just a function of speed. At the moment, it can't
be done, so we have to rely on some nebulous concept of 'in the future the
technology will be developed'. I want to say 'can't be done' but such
challenges continually get overcome by the relentless march of technology. So
I have to say 'can't say can't'. Thus it messes with my head.

------
hugh3
This is exciting, if not surprising, news. We knew that potentially habitable
planets must be out there somewhere, but I'm still very excited that we now
know where the first one is.

Expect to hear the name "Gliese 581g" a lot more in the future, because this
will be the standard hypothetical nearby life-bearing system people will be
talking about for years to come. Habitable and only twenty light years away?

The tidally locked nature of the planet is a bit of a bummer, though. If there
_were_ water on the surface, I wonder what would happen to it. Will there be a
liquid-water ring, or will the water inevitably wind up getting stuck on the
cold side, never to remelt? Perhaps a constant system of glaciers flowing from
cold side to hot side, melting, blowing to the cold side and snowing down
again?

~~~
equark
It's pretty unlikely this will remain highly talked about after Kepler
releases its findings in a few months. Preliminary results show huge numbers
of small earth-like planets. I believe they expect to find dozens or hundreds
in the habitable zone. Kepler is really what everybody is waiting for and
should completely revolutionize planet-finding.

~~~
wlievens
Actually, the most interesting results won't be here til the second half of
2012, if you take the following [somewhat chauvinistic] criteria into account:

\- A really interesting planet orbits a planet similar to the sun.

\- The goldilocks zone around a planet similar to the sun puts it in an orbit
radius of around 1 year (give or take 20% or so) because orbit period is a
function of solar mass and distance.

\- It takes three occurances to be sure that a "dip" you see in light
emissions is probably a _pattern_ rather than a _coincidence_. It's like
colinear points on a plane: two points always make a line, but for three
points to be on a line you're pretty damn lucky.

\- Kepler was launched in 2009.

So in the end of 2012 we'll have a list of (hopefully hundreds of) confirmed
earth-like planets that orbit sol-like stars with a rotation period around 1
year. That is _awesome_.

------
patrickgzill
My first thought was "use big heat pipes to transfer heat from the hot side to
the cool side".

~~~
hugh3
Indeed, anyone living there would not have an energy problem at all.

------
chegra
"Time dilation would make it possible for passengers in a fast-moving vehicle
to travel further into the future while aging very little, in that their great
speed slows down the rate of passage of on-board time. That is, the ship's
clock (and according to relativity, any human travelling with it) shows less
elapsed time than the clocks of observers on Earth. For sufficiently high
speeds the effect is dramatic. For example, one year of travel might
correspond to ten years at home. Indeed, a constant 1 g acceleration would
permit humans to travel as far as light has been able to travel since the big
bang (some 13.7 billion light years) in one human lifetime. The space
travellers could return to Earth billions of years in the future. A scenario
based on this idea was presented in the novel Planet of the Apes by Pierre
Boulle." -
[http://en.wikipedia.org/wiki/Time_dilation#Time_dilation_and...](http://en.wikipedia.org/wiki/Time_dilation#Time_dilation_and_space_flight)

~~~
ugh
"A scenario based on this idea was presented in the novel Planet of the Apes
by Pierre Boulle." — also The Forever War by Joe Haldeman:
<http://en.wikipedia.org/wiki/The_Forever_War>

~~~
warfangle
Also, A World Out of Time, by Larry Niven - where a ramjet pilot returns to
earth, only to find it ruined and way too hot:
<http://en.wikipedia.org/wiki/A_World_Out_of_Time>

------
fleitz
Sweet, it's only 20 light years away. A quick 10 month journey at warp 3.

~~~
nfg
<http://en.wikipedia.org/wiki/Time_dilation>

~~~
akozak
Clearly fleitz is assuming he'll be a passenger.

~~~
hugh3
Talking about warp factors and talking about time dilation don't go well
together, unfortunately. The Star Trek universe is, as best I can figure out,
nonrelativistic.

~~~
texel
This is a bit of hand waving (which is OK because we're talking about
imaginary sci-fi constructs) but it was my understanding that since warp drive
bends space _around_ you, you're not actually going anywhere near the speed of
light, and therefore you experience time similarly relative to people at rest.

~~~
hugh3
I'd have to see that on a Minkowski diagram before I believed it made sense.

~~~
waterlesscloud
Two words- Minkowski Compensators.

~~~
pavel_lishin
Just reverse the phase polarity in the coupler coils.

------
tectonic
From
[http://blogs.discovermagazine.com/badastronomy/2010/09/29/po...](http://blogs.discovermagazine.com/badastronomy/2010/09/29/possible-
earthlike-planet-found-in-the-goldilocks-zone-of-a-nearby-star/)

"But perhaps the most interesting and exciting aspect of all this is what it
implies. The Milky Way galaxy is composed of about 200 billion stars, and is
100,000 light years across. The fact that we found a planet that is even
anything like the Earth at all orbiting another star only 20 light years away
makes me extremely optimistic that earthlike planets are everywhere in our
galaxy. 20 light years is practically in our lap compared to the vast size of
our galaxy, so statistically speaking, it seems very likely it’s not unique. I
don’t want to extrapolate from a data set of two (us and them), but if this is
typical, there could be millions of such planets in the galaxy. Millions."

------
shajith
Does anyone know if the "Message from Earth"[1] sent towards Gliese 581c can
conceivably be received at this new planet?

If there is intelligent life in that system capable of detecting and
transmitting signals of that form (NOT assuming that by any stretch), a
response is due in ~2049.

While we're on that topic, wouldn't such a hypothetical civilization already
have discovered other electromagnetic radiation from our system by now? Or
does it have to be a focused high-power signal as this one?

[1] <http://en.wikipedia.org/wiki/A_Message_From_Earth>

------
Encosia
I find the idea of inhabiting a planet "tidally locked" to its star
fascinating. I'd never heard of such a thing until reading that article.

~~~
dstorrs
IANAP, but it seems pretty unlikely that this would be possible, at least in
any way short of living in underground bunkers. I would expect that either the
atmosphere would boil off from the hot side (if there wasn't enough gravity to
retain it), or the gravity COULD retain it in which case you would get
constant world-wide hurricane force winds.

~~~
hugh3
IAAP but I'm not so sure what would happen, it's nonobvious. I did find this
short article, based on a more thorough research paper from 1997, suggesting
it might be possible though:

<http://www.treitel.org/Richard/rass/tidelock01.txt>

 _In short, not only can such a tide-locked planet maintain an atmosphere, but
it might even be habitable over much of its surface, with an active water
cycle and maybe even a near-breathable surface._

~~~
dstorrs
That is really cool. Thank you for the correction, and for the article.

------
herdrick
This was announced a year or two ago, right - is there anything new there?

EDIT: OK, that was Gliese 581 C. This is the new best hope.

------
tocomment
Do you guys think we'll come up with a catchy name for this planet (or future
"habitable" planets discovered?) Any idea how that naming process would work?

I can't imagine seeing "Gliese 581g" in headlines for years to come.

~~~
mfukar
How about 'Tarsonis'?

~~~
rblion
Bipolarland would work too. It literally has a split planetary personality.

------
nohat
It's amazing to watch the increasing habitability of newly discovered extra-
solar planets. Remember a few years ago when a super jovian was an exciting
discovery? Sure it was an easy assumption: planets ought to be common, if our
system had 9 (yes back before poor pluto was demoted). The spector of the
anthropic principle was always there though. Now, to see the discoveries mount
- as fast and earthlike as our instruments are capable? That's exciting. Hell,
20 light-years? That's not so far away from the planned orion interstellar
trip.

------
christangrant
"The planet is tidally locked to the star, meaning that one side is always
facing the star "

How is the gravity about the same as earths if the planet does not spin, or is
the planet spinning at the same rate that it is revolving around it's star,
like the moon. So I guess gravity does not just come from the centripetal
force. Are there any other forces that contribute to planetary gravity? If not
the planetary year should be very small.

...rambling

~~~
jcl
Gravitational force is dependent on mass, not how much an object is spinning.

~~~
christangrant
So centripetal force is independent from planetary gravitational force...

------
tocomment
A couple more questions. Would the presence of a magnetic field affect
habitability? If so how? How likely is a planet this size to have a magnetic
field like Earth's?

Say we did colonize this planet, would be be able to launch crafts into orbit
from the surface? It seems like our rockets can barely escape Earth's gravity?

------
jarin
That is great, but have they determined whether or not it has unobtainium
deposits yet?

On a serious note, how is it that the planet has 4 times the mass of Earth but
the surface gravity is "the same or slightly higher" than Earth's?

~~~
ramchip
> On a serious note, how is it that the planet has 4 times the mass of Earth
> but the surface gravity is "the same or slightly higher" than Earth's?

It could be bigger than Earth:
[http://www.wolframalpha.com/input/?i=surface+gravity+of+4+ea...](http://www.wolframalpha.com/input/?i=surface+gravity+of+4+earth+mass+and+2+earth+radius)

------
malloreon
Time to blow this popsicle stand! So long, suckers!

------
ankimal
I wonder if we ll reach it on a speed-o-light craft or teleport to it?

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rubashov
> Gliese 581g, has a mass three to four times that of Earth

> The surface gravity would be about the same or slightly higher than Earth's

I'm confused. Maybe it's way less dense than earth, so on the surface you're
far from the center of gravity?

~~~
hugh3
The density is unknown, but we assume it to be rocky because... well, at 2
Earth masses there's not much else it could be made of. It can't be ice
because it's too warm, and it can't be gas because gas planets that size won't
hold together.

But by my calculations a four Earth-mass planet with the same density as Earth
should have gravity of about 1.73g. (using
<http://www.ericjamesstone.com/weird_stuff/gravitator.htm>) Which is not
_that_ similar to Earth gravity, but not too far off either, in the scheme of
things.

~~~
ww520
That's a very cool calculator. I tried to work out the math based on sphere
volume: V=4/3 x PI x R^3.

    
    
      Earth Mass   Radius   Surface Gravity
        1X         6378km        1.00g
        2X         8035km        1.26g
        3X         9198km        1.45g
        4X        10124km        1.59g
        5X        10906km        1.71g
    

If it's 2X or 3X, it's just adding 30% to 40% body weight. For 4X or 5X, it's
like adding 100lb to an 150lb body. We have plenty of people in the 250lb to
350lb range and they have no problem in mobility. Human body can handle the
load. It might still be helpful to have exoskeleton help.

~~~
hugh3
You'd probably still have issues if you tried to live there. Your legs can
support twice your body weight if they need to, but can your neck support a
double-weight head? Human spines are already pretty under-spec for their task,
so people living in 2g gravity would probably suffer from a lot more back
problems.

It's a pretty small-beer problem on the scale of colonise-another-star-system
problems though.

~~~
roc
Not to mention that large humans do take time to become large. A 200 pound man
doesn't wake up one day weighing 340 pounds. Yes, a human body can adapt to
it, massive health problems notwithstanding, but that doesn't mean you can
step off a space craft into that situation. To say nothing of doing so after a
multi-generation trip through bone- and muscle-wasting space.

------
albahk
This is old news - James Cameron already made a documentary about this place.

edit: My point here, not well made, was that the potential of a discovery of
this magnitude, i.e. a virgin planet capable of sustaining humans etc will
eventually be exploited and ruined much the same way we have done to earth.
The earth or this new planet is not the problem, but the way we exist on it.

~~~
anigbrowl
If you were meant to live in perfect harmony with nature, you'd be a tree.

