# http://planetquest.jpl.nasa.gov/TPF/tpf_what_is.htmlAugust 17, 2003 9:09 PM   Subscribe

NASA thinks we can find another Earth in another nearby star. When we do, how can we possibly travel light-years to get there? It might not be as hard as you'd think . . .
posted by stbalbach (31 comments total)

Holy shit. Star Trek indeed.
posted by angry modem at 9:28 PM on August 17, 2003

The author of the second link is named William Speed Weed.
posted by rusty at 9:39 PM on August 17, 2003

"The physics is not out of reach," says Robert Frisbee, an engineer who directs advanced propulsion concepts studies at NASA's Jet Propulsion Laboratory in Pasadena, California.

Yes indeed. Trust a Frisbee to get us there.
posted by coelecanth at 10:13 PM on August 17, 2003

Trust a Frisbee to get us there.

What if the spaceship flies up on the roof and gets stuck there?
posted by kindall at 10:18 PM on August 17, 2003

"A rocket's ultimate speed is limited to about twice the velocity of its nozzle exhaust."

In a vacuum? This makes no sense to me. Would a rocket simply cease to accelerate once it had attained that speed? Why? In a vacuum,the velocity of an object is practically meaningless except in reference to something else. Why would a rocket stop accelerating just because it had achieved some arbitrary speed relative to its point of origin? Can any physicists here explain this to me?
posted by George_Spiggott at 10:41 PM on August 17, 2003

The author of the second link is named William Speed Weed.

there is going to be one hell of an explosion when the antispeedweed reads this.
posted by quonsar at 10:42 PM on August 17, 2003

R: ultimate speed, never mind, I think I understand what he's saying. A rocket must carry reaction mass and throw it out the back really hard in order to accelerate. The upper limit of the speed a rocket can attain relative to its point of origin is a function of the proportion of the total mass that it's carrying which is used for reaction, and how fast you shoot it out the back.

Pardon me for derailing the making fun of names discussion, but it took me a while to make sense of what he was saying.
posted by George_Spiggott at 11:00 PM on August 17, 2003

And you can fly
High as a kite if you want to
Faster than light if you want to
Speeding through the universe
Thinking is the best way to travel

It's all a dream
Light passing by on the screen
And there's you and I on the beam
Speeding through the universe
Thinking is the best way to travel

We ride the waves
Distance is gone, will we find out?
How life began, will be find out?
Speeding through the universe
Thinking is the best way to travel

And you can fly
High as a kite if you want to
Faster than light if you want to
Speeding through the universe
Thinking is the best way to travel

(moody blues high as a kite circa 34 years ago)
posted by five fresh fish at 11:44 PM on August 17, 2003

There are two basic reasons to send people to Earth-like planets:

1) Compare Earth to what has happened elsewhere to help figure out our own world, so we don't screw up;

2) Make a lot of babies somewhere else just in case we screw up (this assumes you think people are a good thing to have around, as I do).
posted by skyscraper at 12:14 AM on August 18, 2003

Funny. We had another recent flight-related post featuring an article (The Flight of the Birdmen) by William Speed Weed. He seems quite widely published, and no wonder... what magazine could resist that byline?
posted by taz at 12:19 AM on August 18, 2003

But will we go?
I say we should at least try. Maybe if we can start spending money the planet cannot afford on finding another world, we can stop spending so much money the planet cannot afford to make better ways of blowing each other up. Just make sure the management consultants and telephone sanitizers are in the first ship.
posted by dg at 12:22 AM on August 18, 2003

In 1903 Russian physicist Konstantin Tsiolkovsky discovered the great impediment to interstellar travel: A rocket's ultimate speed is limited to about twice the velocity of its nozzle exhaust.

Tsiolkovsky's rocket equation only works when the rocket velocity is much less than the exhaust velocity.
posted by eddydamascene at 1:04 AM on August 18, 2003

The author of the second link is named William Speed Weed.
and at the end of the page: Copyright 2003 The Walt Disney Company.

Seriously now, is it possible to use quantum entanglement in astronomy? Entangle 2 photons, send one to Alpha Centauri, keep the other here. When the one in route to AC finds something, observe it on the photon kept captive.
posted by MzB at 1:23 AM on August 18, 2003

Well, you could try using quantum entanglement, but what useful information could you hope to get back? I could see it being used in communications between distant spaceship and earth, but not to gain anything useful.
posted by BigCalm at 1:30 AM on August 18, 2003

if it works:
1. think of it as a radar with no reflection, as the captive photons will provide the info. It might be possible to map a whole system with a laser beam.
2. using the right frequencies one could figure out the chemical composition of the atmosphere (for a planet).

being used in communications between distant spaceship and earth
your case, as mine, implies faster than light communication.
Hmmmm, something is wrong in this picture ... Help!
posted by MzB at 1:59 AM on August 18, 2003

send one to Alpha Centauri, keep the other here

I wonder if you can keep the other here without destroying the entanglement.
posted by eddydamascene at 2:07 AM on August 18, 2003

"In 1903 Russian physicist Konstantin Tsiolkovsky discovered the great impediment to interstellar travel: A rocket's ultimate speed is limited to about twice the velocity of its nozzle exhaust."
"In 1904, Russian physicist Konstantin Tsiolkovsky was found beaten to death with a physics text book"
posted by Freaky at 5:54 AM on August 18, 2003

stbalbach, I assume you are aware that you have munged the title of this otherwise excellent post. Therefore I am pointing this fact out merely to be annoying. Is it working yet?
posted by walrus at 7:03 AM on August 18, 2003

If you're looking for a good (fictional) read on this subject, check out The Sparrow by Mary Doria Russell.
posted by MsVader at 8:12 AM on August 18, 2003 [1 favorite]

We can't do it. Once we leave the solar system the scary space serpents will surely devour us! There be monsters there!
posted by effer27 at 8:13 AM on August 18, 2003

One dictum I've heard that may have some merit goes something like: "by the time we've achieved the ability to physically travel to other stars we won't want to." Overcoming the barriers to practical interstellar travel implies a degree of technical sophistication that would be, from our current perspective, godlike. By the time we achieve it (if we do), we might very well be able to create any kind of reality we can imagine, and have no need of, or interest in, physically moving our carcasses across interstellar distances.

I don't assert that this is true, just that it's been said, and seems not unreasonable.
posted by George_Spiggott at 8:43 AM on August 18, 2003

We live with the knowledge that someday, even if we're lucky enough to avoid nuclear, meteoric, and environmental destruction, that eventually, the Earth and everything on it will be destroyed by the sun's death throes in something like 5 billion years.

5 billion years is a long time, but even so, we can have no illusions about the permanence of life as we know it or any remnant of our civilization or culture.

Dire as it is, it's one of the cornerstones of my understanding of the world. I'm not sure I want to let it go.
posted by scarabic at 9:01 AM on August 18, 2003

this assumes you think people are a good thing to have around, as I do

Well, you would, wouldn't you, hu-mon? I suspect whoever may be out there already has different views on the subject if they've been paying any attention to the mess we've made of this particular galactic backwater.
posted by languagehat at 12:09 PM on August 18, 2003

Last night he could not make it
He tried hard but could not make it
Last night he could not make it
On a holiday
So many miles
Looking for a place to stay
Near some friendly star
He found this mote
Now we wonder....
posted by wobh at 12:49 PM on August 18, 2003

We come from a blue planet light-years away
Where everything multiplies at an amazing rate
We're out here in the universe buying real estate
Hope we haven't gotten here too late

We're looking for a planet with atmosphere
Where the air is fresh and the water clear
With lots of sun like you have here
Three or four hundred days a year

Bought Manhatten for a string of beads
Brought along some gadgets for you to see
Heres a crazy little thing we call TV
Do you have electricity?

I know we may seem pretty strange to you
But we got know-how and a golden rule
We're here to see manifest destiny through
Ain't nothing we can't get used to

We're humans from earth
We're humans from earth
You have nothing at all to fear
I think we're gonna like it here
posted by NortonDC at 1:06 PM on August 18, 2003

You guys ruined a perfectly good post. What the fuck?
posted by Hildago at 1:49 PM on August 18, 2003

languagehat, why do you hate Earth so much?
posted by George_Spiggott at 5:15 PM on August 18, 2003

Earth haters unite!
posted by wobh at 7:08 PM on August 18, 2003

Scarabic, I was teaching an astronomy class a while back and I mentioned the five billion year sun engulfs earth doomsday. After class, a respectable woman in her 50s approached me as said, "Did you say the Earth will be destroyed by the sun in five million years?" To which I replied, "No, I said five billion years." The woman let out a relieved sigh. True story.
posted by squirrel at 10:24 PM on August 18, 2003

hmm
I haven't finished the article, and I don't doubt nor oppose there will be explorers, but his analogy is flawed.

There will not be random commonfolk setting out into space because regular people cannot afford nor have the technology for such endeavors. There is no thriving aerospace culture that regularl sends people up into space whenever they feel like it. Perhaps in the future you say. Perhaps there will be commercial companies using government technology to satisfy the curiosity of rich tourists. But what about adventurous people, willing to leave the old world? What about the actual planning and development of the technology for an interstellar expedition?

Of course in the far future things may be different. But I'm talking about when we find this baby. The aerospace culture needs to resemble sailboats and not airplanes. It is relatively easy for anybody to learn how to and build their own boat, then sail off if they wanted to. Not so for airplanes, and not so with space technology.
posted by firestorm at 3:56 PM on August 19, 2003

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