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GnarleyMarley
Apr 25, 2007, 02:40 AM
http://www.cnn.com/2007/TECH/space/04/25/habitable.planet.ap/index.html

http://i.a.cnn.net/cnn/2007/TECH/space/04/25/habitable.planet.ap/story.gliese.afp.gi.jpg

WASHINGTON (AP) -- European astronomers have found the most Earth-like planet outside our solar system, and here's what it might be like to live there:

The "sun" wouldn't burn brightly. It would hang close, large and red in the sky, glowing faintly like a charcoal ember. And it probably would never set if you lived on the sunny side of the planet.

You could have a birthday party every 13 days because that's how fast this new planet circles its sun-like star. But watch the cake -- you'd weigh a whole lot more than you do on Earth.

You might be able to keep your current wardrobe. The temperature in this alien setting will likely be a lot like Earth's -- not too hot, not too cold.

And that "just right" temperature is one key reason astronomers think this planet could conceivably house life outside our solar system. It's also as close to Earth-sized as telescopes have ever spotted. Both elements make it the first potentially habitable planet besides Earth or Mars.

Astronomers who announced the discovery of the new planet Tuesday say this puts them closer to answering the cosmic question: Are we alone?

"It's a significant step on the way to finding possible life in the universe," said University of Geneva astronomer Michel Mayor, one of 11 European scientists on the team that found the new body. "It's a nice discovery. We still have a lot of questions."

There's still a lot that is unknown about the new planet, which could be deemed inhospitable to life once more is learned about it. But as galaxies go, it's practically a neighbor. At only 120 trillion miles away, the red dwarf star that this planet circles is one of the 100 closest to Earth.

The results of the discovery have not been published but have been submitted to the journal Astronomy and Astrophysics.

Alan Boss, who works at the Carnegie Institution of Washington where a U.S. team of astronomers competed in the hunt for an Earth-like planet, called it "a major milestone in this business."

The planet was discovered by the European Southern Observatory's telescope in La Silla, Chile, which has a special instrument that splits light to find wobbles in different wavelengths. Those wobbles can reveal the existence of other worlds.

What they revealed is a planet circling the red dwarf star, Gliese 581. Red dwarfs are low-energy, tiny stars that give off dim red light and last longer than stars like our sun. Until a few years ago, astronomers didn't consider these stars as possible hosts of planets that might sustain life.

The discovery of the new planet, named 581 c, is sure to fuel studies of planets circling similar dim stars. About 80 percent of the stars near Earth are red dwarfs.

The new planet is about five times heavier than Earth, and gravity there would be 1.6 times as strong as Earth's. Its discoverers aren't certain if it is rocky like Earth or if its a frozen ice ball with liquid water on the surface. If it is rocky like Earth, which is what the prevailing theory proposes, it has a diameter about 11/2 times bigger than our planet. If it is an iceball, as Mayor suggests, it would be even bigger.

Based on theory, 581 c should have an atmosphere, but what's in that atmosphere is still a mystery and if it's too thick that could make the planet's surface temperature too hot, Mayor said.

However, the research team believes the average temperature to be somewhere between 32 and 104 degrees and that set off celebrations among astronomers.

Until now, all 220 planets astronomers have found outside our solar system have had the "Goldilocks problem." They've been too hot, too cold or just plain too big and gaseous, like uninhabitable Jupiter.

The new planet seems just right -- or at least that's what scientists think.

"This could be very important," said NASA astrobiology expert Chris McKay, who was not part of the discovery team. "It doesn't mean there is life, but it means it's an Earth-like planet in terms of potential habitability."

Eventually astronomers will rack up discoveries of dozens, maybe even hundreds of planets considered habitable, the astronomers said. But this one -- simply called "c" by its discoverers when they talk among themselves -- will go down in cosmic history as No. 1.

Besides having the right temperature, the new planet is probably full of liquid water, hypothesizes Stephane Udry, the discovery team's lead author and another Geneva astronomer. But that is based on theory about how planets form, not on any evidence, he said.

"Liquid water is critical to life as we know it," co-author Xavier Delfosse of Grenoble University in France, said in a statement. "Because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extraterrestrial life. On the treasure map of the Universe, one would be tempted to mark this planet with an X."

Other astronomers cautioned it's too early to tell whether there is water.

"You need more work to say it's got water or it doesn't have water," said retired NASA astronomer Steve Maran, press officer for the American Astronomical Society. "You wouldn't send a crew there assuming that when you get there, they'll have enough water to get back."

The new planet's star system is a mere 20.5 light years away, making Gliese 581 one of the 100 closest stars to Earth. It's so dim, you can't see it without a telescope, but it's somewhere in the constellation Libra, which is low in the southeastern sky during the mid-evening in the Northern Hemisphere.

Even so, Maran noted, "We don't know how to get to those places in a human lifetime."

But, oh, the view, if you could. The planet is 14 times closer to the star it orbits. Udry figures the red dwarf star would hang in the sky at a size 20 times larger than our moon. And it's likely, but still not known, that the planet doesn't rotate, so one side would always be sunlit and the other dark.

Two teams of astronomers, one in Europe and one in the United States, have been racing to be the first to find a planet like 581 c outside the solar system.

The European team looked at 100 different stars using a tool called HARPS (High Accuracy Radial Velocity for Planetary Searcher) to find this one planet, said Xavier Bonfils of the Lisbon Observatory, one of the co-discoverers.

Much of the effort to find Earth-like planets has focused on stars like our sun with the challenge being to find a planet the right distance from the star it orbits. About 90 percent of the time, the European telescope focused its search more on sun-like stars, Udry said.

A few weeks before the European discovery earlier this month, a scientific paper in the journal Astrobiology theorized a few days that red dwarf stars were good candidates.

"Now we have the possibility to find many more," Bonfils said.

Abstract
Apr 25, 2007, 07:19 AM
Little do they know that once us humans step foot on that planet, we're going to find a flag planted into the ground that says "Chuck Norris Was Here." *shakes head*

Queso
Apr 25, 2007, 07:31 AM
I like the fact they think it doesn't spin. I take it this means roughly one half of the planet is going to be frozen waste, if there's water that is.

I wonder how many others there are out there.

BTW, on a ever-so-slightly related astronomical note, has anyone seen just how big the star Antares (http://en.wikipedia.org/wiki/Antares) is compared to our Sun? :eek:

dmw007
Apr 25, 2007, 08:06 AM
Well, I suppose it looks like we found a replacement for our planet once we finally kill it. ;)

Actually, it is a cool discovery. Now we just need to figure out a way to get there. :)

Queso
Apr 25, 2007, 08:38 AM
Well, I suppose it looks like we found a replacement for our planet once we finally kill it. ;)

Actually, it is a cool discovery. Now we just need to figure out a way to get there. :)
Hollow out Juno, set it spinning, name it Thistledown and send it off.

Scarlet Fever
Apr 25, 2007, 08:55 AM
BTW, on a ever-so-slightly related astronomical note, has anyone seen just how big the star Antares (http://en.wikipedia.org/wiki/Antares) is compared to our Sun? :eek:

wheres the jaw-dropping smilie when you need it...

Queso
Apr 25, 2007, 08:59 AM
wheres the jaw-dropping smilie when you need it...
Not to thread hijack, but here's a quick comparison off Wikipedia, showing our Sun, Arcturus and Antares to scale. That's one BIG ball of gas!!

http://upload.wikimedia.org/wikipedia/en/thumb/a/a6/Arcturus-antares-2.gif/551px-Arcturus-antares-2.gif

The black line BTW isn't the dimensions of Antares, but the orbit of Mars to the same scale. Antares stretches out to the edges of the yellow/orange circle. Sat at the centre of our Solar System, Antares would nearly reach the orbit of Jupiter.

PlaceofDis
Apr 25, 2007, 09:19 AM
interesting. perhaps it has a very slow rotation though? suppose it'd take a while to figure out though.

and that picture is astounding dynamicv.

mattscott306
Apr 25, 2007, 09:19 AM
Not to thread hijack, but here's a quick comparison off Wikipedia, showing our Sun, Arcturus and Antares to scale. That's one BIG ball of gas!!

The black line BTW isn't the dimensions of Antares, but the orbit of Mars to the same scale. Antares stretches out to the edges of the yellow/orange circle. Sat at the centre of our Solar System, Antares would nearly reach the orbit of Jupiter.

I wonder how far in comparison to our sun does a planet have to be to sustain life...

QCassidy352
Apr 25, 2007, 09:22 AM
I find it interesting, though, that Mars also satisfies the definition of an "earth-like planet" that is being applied to this planet. So it would not necessarily be suitable for human habitation...

Marble
Apr 25, 2007, 11:16 PM
If it doesn't rotate isn't it unlikely to have a magnetic field strong enough to shield the planet from solar radiation?

Keebler
Apr 26, 2007, 10:18 AM
i think it's kind of neat, but it makes me wonder how long it would take us to get there. maybe we need to make some 'how to dvds', set up an invetro tube and launch a baby or 2 or more ;) and launch it towards that planet :)

if we could only put half the effort into repairing this planet's problems, maybe we wouldn't need to worry about another one :)

notjustjay
Apr 26, 2007, 12:07 PM
So is this a Class M planet? :D

I read in our local papers that with our current-fastest spacecraft technology, it would take us 5 billion years to get there.

We really need to work on lightspeed travel.

faintember
Apr 26, 2007, 12:13 PM
That looks totally cool, and would lead to a great sequel: Dark Side of the 581 c
Please send all flames to my private message inbox. Thanks!
We really need to work on lightspeed travel.We really need to work on doing something other than launching missions to the ISS.

PlaceofDis
Apr 26, 2007, 12:27 PM
I find it interesting, though, that Mars also satisfies the definition of an "earth-like planet" that is being applied to this planet. So it would not necessarily be suitable for human habitation...

i do too. but its probably due to the size, proximity to us, and other similar aspects. being in our solar system makes mars the most easily accessible planet for us to get to, and try to sustain life on at this point in time.

Jaffa Cake
Apr 26, 2007, 02:12 PM
The discovery of the new planet, named 581 c...

Very sexy name there, although to be fair the fact that it's in the 'Goldilocks zone' does make up for it a bit.

Diatribe
Apr 26, 2007, 02:32 PM
We really need to work on doing something other than launching missions to the ISS.

Nah, we're busy spending all our money killing ourselves. No time nore money to explore space. :p

dartzorichalcos
Apr 26, 2007, 05:55 PM
I would want to go and explore that planet. If that's ever possible.

Eric5h5
Apr 26, 2007, 06:59 PM
I read in our local papers that with our current-fastest spacecraft technology, it would take us 5 billion years to get there.

Holy mackerel, the math skills of your local papers are going down the toilet, not to mention knowledge of science. Maybe it would take that long if you walked. :rolleyes: The speed of light is "only" 186,000 miles per second or so. That comes out to more like 90,000 years (give or take a few thousand) at 150,000 mph, which you could probably achieve with a slingshot maneuver using traditional rockets. Plus we have ion drive technology now, which has ten times the thrust-per-pound of fuel compared to those traditional rockets. As long as you don't mind the leisurely pace of acceleration...how does 0 to 60 in 4 days sound. ;) But the thing with space is, there's no friction, so you can accelerate forever as long as you have enough fuel. Or until you reach the speed of light, which is the only speed limit that matters. :) So I'm sure we could shave off thousands of years from that time.

Anyway, not anywhere near 5 billion years...what dingbat came up with that figure. But not quite an afternoon's drive, either....

--Eric

dmw007
Apr 27, 2007, 08:15 AM
Not to thread hijack, but here's a quick comparison off Wikipedia, showing our Sun, Arcturus and Antares to scale. That's one BIG ball of gas!!




Wow, that is quite the difference in size! :eek: :D

noaccess
Apr 27, 2007, 09:06 AM
Found an even bigger star (http://en.wikipedia.org/wiki/LBV_1806-20). It's toward the center of our galaxy.

http://upload.wikimedia.org/wikipedia/en/1/13/LBV_1806-20.jpg

EDIT: Or this even bigger one (http://en.wikipedia.org/wiki/Vv_cephei). Link (http://upload.wikimedia.org/wikipedia/commons/c/c7/Sun_and_VV_Cephei_A.png) to full image.

Diatribe
Apr 27, 2007, 09:27 AM
A cool site to see how big stars are:

The size of our world (http://www.rense.com/general72/size.htm)

orangemacapple
Apr 27, 2007, 09:52 AM
so... we found a planet that has a temperate climate and can sustain life. with that info, it stands to reason there is life there already (given the same building blocks for life is abundant).

so, are we going to go there and war with them for the right to live there. i doubt they really want us any more than we would want an alien life to come take over our planet.

we would have to kill all the intelligent life there to take over the planet. look what we did when we found the new world (americas). we killed 160m natives either through war or disease and relegated the rest to uninhabitable regions. we'll have to do the same thing there.

why would they give up everything peacefully? we are not a peaceful race. we would not allow them to govern us. we feel we have a divine right to this universe. we are the best.

we've just about killed our planet, and rather than fix it we would rather go find another one to conquer and devastate.

WOULD YOU GO TO BE A SLAVE TO AN ALIEN RACE? of course not -- you would make them your slaves.

we would pillage their planet of resources. think about what america currently does for oil. look what europe did to america for gold.

we have a population explosion. the new planet probably does too -- or needs the room to expand on its own if it doesn't have that problem yet. why do we have the right to take someone else's home away from them. if there is a god, i don't think he'd very happy with our actions.

LEAVE THEM BE! but that's not how it'll be -- there'll always be that little niggling in our minds now that we've found this new "EDEN".

notjustjay
Apr 27, 2007, 10:03 AM
Holy mackerel, the math skills of your local papers are going down the toilet, not to mention knowledge of science. Maybe it would take that long if you walked. :rolleyes: The speed of light is "only" 186,000 miles per second or so.

I admit that I did not really double-check their math. Granted, I also assumed speeds demonstrated by older spacecraft.

Assume the distance from Earth to the outer planets is about 5 light-hours.

It took our Voyager satellites some... 25-30 years to achieve this distance?

This new planet is 20 light years away, or about 175,000 light-hours.

OK, so that's about one million years. Phew. Perhaps there's hope for mankind after all ;)

... yes, you're right, there are probably ways to go much faster than Voyager satellites did.

Now I'm starting to wonder just where my newspaper got its numbers.

obeygiant
Apr 27, 2007, 10:05 AM
so, are we going to go there and war with them for the right to live there. i doubt they really want us any more than we would want an alien life to come take over our planet.


The odds are ok to find life on another planet, but to find intelligent life is another matter. By the time the human race actually gets to the point of exploring extra-solar worlds things will be much different. To live 581 c might require a change in the way we breathe air or a change in our physiology. They say 581 c has 1.6 times the gravity of the earth. So after a few generations of humans living there people may start to get shorter and have much denser muscles in order to adapt to the environment.

Queso
Apr 27, 2007, 10:08 AM
EDIT: Or this even bigger one (http://en.wikipedia.org/wiki/Vv_cephei). Link (http://upload.wikimedia.org/wikipedia/commons/c/c7/Sun_and_VV_Cephei_A.png) to full image.
Wow. Now that one's enormous. Almost out as far as Saturn :eek:

The odds are ok to find life on another planet, but to find intelligent life is another matter. By the time the human race actually gets to the point of exploring extra-solar worlds things will be much different. To live 581 c might require a change in the way we breathe air or a change in our physiology. They say 581 c has 1.6 times the gravity of the earth. So after a few generations of humans living there people may start to get shorter and have much denser muscles in order to adapt to the environment.
I do remember reading an article a few years ago which described how humans living on Mars would likely evolve after a few generations. It had them as over 10 feet tall with all sorts of weird mutations going on.

I'll see whether I can find it, but I think it predates the Web so it may be a fool's errand.

orangemacapple
Apr 27, 2007, 10:14 AM
The odds are ok to find life on another planet, but to find intelligent life is another matter. By the time the human race actually gets to the point of exploring extra-solar worlds things will be much different. To live 581 c might require a change in the way we breathe air or a change in our physiology. They say 581 c has 1.6 times the gravity of the earth. So after a few generations of humans living there people may start to get shorter and have much denser muscles in order to adapt to the environment.

what life on THIS planet is NOT intelligent. do we feel that if they are non-humanoid they are not intelligent. what have we done to the whales and other aquatic life. how many species of land and aquatic life are now extinct or nearly so. we view them as either food or pests or useful for manufacturing processes.

Airforce
Apr 27, 2007, 10:20 AM
what life on THIS planet is NOT intelligent.

Bacteria, my dog isn't too intelligent, the bug I killed earlier outside wasn't too bright.....:D

orangemacapple
Apr 27, 2007, 10:27 AM
Bacteria, my dog isn't too intelligent, the bug I killed earlier outside wasn't too bright.....:D

EXACTLY! in YOUR mindset he has no intelligence. did you stop to think what his role is and his mission? (he probably eradicates refuse or pollinates flowers).

but YOU, in your mighty intelligence just squashed him, for nothing more than the pleasure of killing -- seeing his guts spayed all over.

Airforce
Apr 27, 2007, 10:29 AM
EXACTLY! in YOUR mindset he has no intelligence. did you stop to think what his role is and his mission? (he probably eradicates refuse or pollinates flowers).

but YOU, in your mighty intelligence just squashed him, for nothing more than the pleasure of killing -- seeing his guts spayed all over.

Crazy hippy :p

orangemacapple
Apr 27, 2007, 10:33 AM
Crazy hippy :p
but it's people like me that allow you to live. but there are others not of this mindset (like the kid in va tech... and don't forget g w bush is in your (and that kid's) same mindset also)

obeygiant
Apr 27, 2007, 10:57 AM
what life on THIS planet is NOT intelligent. do we feel that if they are non-humanoid they are not intelligent. what have we done to the whales and other aquatic life. how many species of land and aquatic life are now extinct or nearly so. we view them as either food or pests or useful for manufacturing processes.

Well, simply put, there is bacteria and algae. Then animals :). Then animals that can build rocketships and lazer blasters. These type of animals is what i was referring to. This wasn't meant to be a political discussion. Finding some kind of bactieria or chlorophyll on another planet or moon is distinct possibility.

paddy
Apr 27, 2007, 11:05 AM
but it's people like me that allow you to live.

I suppose I should say thanks then.???

Diatribe
Apr 27, 2007, 11:07 AM
Without wanting to turn this into a political discussion, but imagine if all the money spent on wars and armies would be used on research. We'd know all about our planet and would be travelling to other stars in no time.

Airforce
Apr 27, 2007, 11:13 AM
Without wanting to turn this into a political discussion, but imagine if all the money spent on wars and armies would be used on research. We'd know all about our planet and would be travelling to other stars in no time.

But I'd be out of a job...:eek: :p

Diatribe
Apr 27, 2007, 11:16 AM
But I'd be out of a job...:eek: :p

But you could fly to other planets... (professionally I mean) :p

obeygiant
Apr 27, 2007, 11:19 AM
Without wanting to turn this into a political discussion, but imagine if all the money spent on wars and armies would be used on research. We'd know all about our planet and would be travelling to other stars in no time.

I agree. However, in today's world there would have to be financial incentive for everybody to get excited about space travel. When they find an asteroid filled with copper ore or some other ore, the world's first trillionairs will be made by mining and delivering the goods back to earth.

Queso
Apr 27, 2007, 11:20 AM
Without wanting to turn this into a political discussion, but imagine if all the money spent on wars and armies would be used on research. We'd know all about our planet and would be travelling to other stars in no time.
I wondered about that. The $450bn spent so far on Iraq would probably have gotten us quite a bit closer to nuclear fusion.

Although they'd probably immediately use it to power weapons :rolleyes:

orangemacapple
Apr 27, 2007, 11:23 AM
Well, simply put, there is bacteria and algae. Then animals :). Then animals that can build rocketships and lazer blasters. These type of animals is what i was referring to. This wasn't meant to be a political discussion. Finding some kind of bactieria or chlorophyll on another planet or moon is distinct possibility.

but how long does it really take for simple life to evolve into "intelligent" life?

there is of course a lag in what we are now perceiving from that distant star and the considerable length of time it has been in such a habitable mode before we observed it. add that to the time it will take us to increase our technology to get there and the time to actually traverse that distance, i think that would be significant time for life to evolve to intelligent life.

given that the building blocks for life are abundant everywhere and "sex" is an inherent trait among atoms, evolution/mutation is quickly assured.

obeygiant
Apr 27, 2007, 11:48 AM
I wondered about that. The $450bn spent so far on Iraq would probably have gotten us quite a bit closer to nuclear fusion.

Although they'd probably immediately use it to power weapons :rolleyes:

If they used the war budget for space, we'd probably have a moon base by now. Which is the next step to putting someone on Mars.

obeygiant
Apr 27, 2007, 11:51 AM
but how long does it really take for simple life to evolve into "intelligent" life?

there is of course a lag in what we are now perceiving from that distant star and the considerable length of time it has been in such a habitable mode before we observed it. add that to the time it will take us to increase our technology to get there and the time to actually traverse that distance, i think that would be significant time for life to evolve to intelligent life.

given that the building blocks for life are abundant everywhere and "sex" is an inherent trait among atoms, evolution/mutation is quickly assured.

Im just guessing here but for single celled organisms to evolve into thinking animals would be in the order of millions of years. But if 581 c has something like cave people, if we left now by the 90,000 years to get there they could have an entire civilization, or they could meet us half way.

Jaffa Cake
Apr 27, 2007, 11:54 AM
but how long does it really take for simple life to evolve into "intelligent" life?Once 'intelligent' life has evolved on our planet we might be better placed to make an estimate. ;)

FJ218700
Apr 27, 2007, 12:23 PM
even substituting "multicellular" for "intelligent" and assuming similar evolutionary pressures and organic compositions for each, it would take 3 BILLION yrs to go from unicelluar (bacterial precursors) -- > compartmentatized unicelluar organisms (eukaryotes) --> mullticelluar eukaryotes

Eric5h5
Apr 27, 2007, 12:28 PM
But if 581 c has something like cave people, if we left now by the 90,000 years to get there they could have an entire civilization, or they could meet us half way.

Better make darn sure to get the directions right when we meet half-way. I can hear it now: "Hello? Where the heck are you guys? I said turn LEFT at Alpha Centauri! LEFT! Now you're going to have to turn around and waste another 20,000 years backtracking...stupid cave people anyway...."

--Eric

obeygiant
Apr 27, 2007, 01:07 PM
Better make darn sure to get the directions right when we meet half-way. I can hear it now: "Hello? Where the heck are you guys? I said turn LEFT at Alpha Centauri! LEFT! Now you're going to have to turn around and waste another 20,000 years backtracking...stupid cave people anyway...."

--Eric

lol, i hope the cave people on 581c have Verizon. I can't imagine they'd be 'in-network' tho.

Marble
Apr 27, 2007, 02:13 PM
Besides, by the time the space voyage is over, the 'cave people' would probably have developed into an advanced technological society.

orangemacapple
Apr 27, 2007, 02:21 PM
i don't think we have to worry too much about going there. i'm positive it's already be colonized by the daleks or klingons. at least that's what i heard on the interstellar radio news broadcast.

we're not the only ones in search of a new place to live.

Cromulent
Apr 27, 2007, 02:21 PM
We really need to work on lightspeed travel.

Isn't it impossible to travel at the speed of light due to the effects it has on time? I mean if you travel at the speed of light you would see the same thing for your entire journey as you would be keeping pace with the light and therefore no new light would hit your retinas. Or am I completely wrong on that?

plinden
Apr 27, 2007, 02:23 PM
I wonder where they got the gravity as being 1.6x earths. At 1.5 x the radius and five times the mass, I get 2.2g (5/1.5^2)

Isn't it impossible to travel at the speed of light due to the effects it has on time? I mean if you travel at the speed of light you would see the same thing for your entire journey as you would be keeping pace with the light and therefore no new light would hit your retinas. Or am I completely wrong on that?
Yes, you're wrong. The speed of light is a constant for all observers, so even if you're travelling at .99c, the light hitting your retinas will be travelling at the same speed from all directions. The colour of the light coming from external sources will be different - shifted to the red behind you and shifted to the blue in front - but you wouldn't notice any difference in the appearance of the space craft or any of the crew since you are relatively (in the physics sense of the word) stationary.

orangemacapple
Apr 27, 2007, 02:24 PM
Isn't it impossible to travel at the speed of light due to the effects it has on time? I mean if you travel at the speed of light you would see the same thing for your entire journey as you would be keeping pace with the light and therefore no new light would hit your retinas. Or am I completely wrong on that?
no, because you would be looking where you're going. if you looked behind you it would be the same never-ending thing that you can't get away from.

orangemacapple
Apr 27, 2007, 02:29 PM
I wonder where they got the gravity as being 1.6x earths. At 1.5 x the radius and five times the mass, I get 2.2g (5/1.5^2)
what does mass have to do with radius? the radius of a ton of feathers has no more mass than a ton of bricks. that's like multiplying bricks times feathers to get gravity.

plinden
Apr 27, 2007, 02:35 PM
what does mass have to do with radius? the radius of a ton of feathers has no more mass than a ton of bricks. that's like multiplying bricks times feathers to get gravity.

Sigh ... the gravitational force of any object X at any distance is proportional to its mass and inversely proportional to the square of the distance.

Force on 1kg at surface of Earth = GMe/Re^2 (G = gravitional constant, Me = mass of earth, Re = radius of earth)

Force on 1kg at surface of Planet = Gx5Me/(1.5xRe)^2 = 5/(1.5^2)xGMe/Re^2 = 5/(1.5^2) x force on 1kg on Earth.

Gravitional force on surface of planet = 2.2g.

QED.

(Edit: and before you jump in again, kg is a measurement of mass which is constant whatever the force of gravity is. It's weight that would differ and weight != mass)

Edit 2:
no, because you would be looking where you're going. if you looked behind you it would be the same never-ending thing that you can't get away from.
I hope you're just pulling his leg.

orangemacapple
Apr 27, 2007, 02:50 PM
I hope you're just pulling his leg.


yes, i was pulling his leg, but it makes more sense.

MacNut
Apr 27, 2007, 02:58 PM
Better make darn sure to get the directions right when we meet half-way. I can hear it now: "Hello? Where the heck are you guys? I said turn LEFT at Alpha Centauri! LEFT! Now you're going to have to turn around and waste another 20,000 years backtracking...stupid cave people anyway...."

--EricI hope they are using GEICO.:p

CorvusCamenarum
Apr 27, 2007, 03:30 PM
Isn't it impossible to travel at the speed of light due to the effects it has on time?

Actually it's a problem of mass and energy, as they are interchangable (E=mc^2). As acceleration and velocity increase, so does mass, as you're constantly putting more energy into it. More mass means more energy needed to apply more acceleration. Long story short, to attain a velocity of c requires an infinite amount of energy. You can get closer and closer to c, but barring the discovery of warp drive, you'll never get completely there.

orangemacapple
Apr 27, 2007, 04:09 PM
Actually it's a problem of mass and energy, as they are interchangable (E=mc^2). As acceleration and velocity increase, so does mass, as you're constantly putting more energy into it. More mass means more energy needed to apply more acceleration. Long story short, to attain a velocity of c requires an infinite amount of energy. You can get closer and closer to c, but barring the discovery of warp drive, you'll never get completely there.

actually, i've solved the problem of going faster than the speed of light.

when you pass the speed of light, time travel becomes possible.

the error everyone seems to be making is the energy required to exceed 186,000 miles per second. the expenditure of energy becomes prohibitive.

there is a much better way to do it!

slow down light. we already know how to do that. now, we just need to put a spaceship in the slowed light stream and we can travel that 90k years in no time at all.

there's always more than one way to skin a cat.

book coming soon!

Erasmus
Apr 27, 2007, 07:38 PM
If you can pull an accelleration of a full g all the way (Well, half way and a full g decel, cos there's no point getting there travelling at 20 trillion m/s) you can get there in 8.8 years. Not bad, eh? Of course the problem is getting the fuel to do it. Fusion might work, but Antimatter would be optimal.

New life goal...

Oh, and about the problem of moving faster than the speed of light. True, you can't, but when you travel at very high speeds, time dialation / length contraction (Which are really the same thing, just from different points of view) means that the person doing the acceleration can get to somewhere 20.4 light years away in less than 9 years. It will take more like 25 years (plus 20.4 year light speed communication time) for someone on Earth to see them get there.

Erasmus
Apr 27, 2007, 07:43 PM
I wondered about that. The $450bn spent so far on Iraq would probably have gotten us quite a bit closer to nuclear fusion.

Although they'd probably immediately use it to power weapons :rolleyes:

You may already know this, but nuclear fusion powered weapons already exist. They are called thermonukes. ie. normal nuke sets off nuclear fusion chain reaction making bigger explosion. First one was set off over Bikini Atoll a very long time ago???

obeygiant
Apr 27, 2007, 08:16 PM
If you can pull an accelleration of a full g all the way (Well, half way and a full g decel, cos there's no point getting there travelling at 20 trillion m/s) you can get there in 8.8 years. Not bad, eh? Of course the problem is getting the fuel to do it. Fusion might work, but Antimatter would be optimal.


Don't forget you'd have to slow down!

Here (http://en.wikipedia.org/wiki/Interstellar_travel) is a interesting Wiki article about interstellar travel.

Erasmus
Apr 27, 2007, 08:21 PM
Don't forget you'd have to slow down!

Here (http://en.wikipedia.org/wiki/Interstellar_travel) is a interesting Wiki article about interstellar travel.

Hence the bit in brackets. I took account of that. If you didn't need to slow down, the time taken would be a LOT less.

plinden
Apr 27, 2007, 09:06 PM
If you can pull an accelleration of a full g all the way (Well, half way and a full g decel, cos there's no point getting there travelling at 20 trillion m/s) you can get there in 8.8 years. .
No, because that would imply you would be going faster than the speed of light The planet is 20.5 light years away ... that's the minimum time anything would take to get there.

Erasmus
Apr 27, 2007, 09:11 PM
No, because that would imply you would be going faster than the speed of light The planet is 20.5 light years away ... that's the minimum time anything would take to get there.

I'm sorry, but it is YOU who is mistaken.

The concept of not being able to break the speed of light only applies for stationary observers.

If you travel at high speed, length contraction means the distance you have to travel will be shorter. This means that it IS possible to reach this planet in less than 9 years.

Different observers see different things. A stationary observer would see the spacecraft taking over 20.4 years to get to the planet.

Trust me... I'm a future Rocket Scientist : ) I do know what I'm talking about, but if you insist on arguing, I'm happy to oblige ; )

mattscott306
Apr 27, 2007, 10:07 PM
Kind of like that movie contact except opposite?

Erasmus
Apr 27, 2007, 10:34 PM
Kind of like that movie contact except opposite?

Well, yes, but no, no and no.

Clocks on fast moving things run slower then clocks that don't. ie. Atomic clock on 747 and flown around the world when compared to atomic clock left on ground showed a discrepancy too large to be an error. Also, particles created in the upper atmosphere by cosmic rays should never survive long enough to make it to the ground, but they are frequently detected here, because of time dilation / length contraction.

I believe the movie Contact featured wormholes, and so the person wasn't actually moving... So, bad analogy.

plinden
Apr 28, 2007, 02:22 AM
if you insist on arguing, I'm happy to oblige ; )
No, I'm not going to argue. Your original unedited comment made no mention of time dilation.

Since I'm never going to go above 30,000 feet, I look at from my point of view. It's all relative.

Erasmus
Apr 28, 2007, 02:36 AM
No, I'm not going to argue. Your original unedited comment made no mention of time dilation.

Since I'm never going to go above 30,000 feet, I look at from my point of view. It's all relative.

OK, I suppose that's true, but I did edit my post to add the extra bit immediately after posting.

And if you replied immediately after I submitted my unedited post, it took you, what... 25 minutes to write two lines???