Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[ISP]

Even if aliens right now exist on alpha-centauri Bb that just now learned to use radio waves, they would know about us instantly, we would have to wait over 4 years to find out, and if they all died out over 200 years ago we would never have received their messages, in the span that planets can support intelligent enough life to use technology like radio waves to when intelligent species either possibly destroy themselves or learn better ways to communicate over distances, lets say between 200 to 1000 years... its very possible that life could have come about asked us if we were friendly and the only things on earth were perhaps dinosaurs... lets say there is life, is it even smart enough to do anything than eat and hunt?
Or is it so smart it doesnt deam us important enough for anything besides study?

The posibility that a civilization equivilent to ours will develope in one particular system within our timespan of us knowing what to look for and being around to hear or care is just rubbishly low, the posibility that we're going to hear some ancient alien garbage from some distant civilization is just about as low... I'd bet on winning the lottery with numbers I got off a winning lottery ticket I just won on again then hearing anything from space that shows intelligent origin.

What if we do hear the remnant of some alien species, unless its within out neighborhood we wont have any way to practicly communicate anything but confirmation that yes indeed they are aliens, alpha centauri would take over 8 years to send a message and get it back and thats the closest and thus shortest, it would be a life's work just to communicate with aliens and thats not even just the distance.

[Eagleon]

It's very likely our instruments aren't powerful enough yet, even to confirm that they're not in Alpha Centauri. http://www.computing.edu.au/~bvk/astronomy/HET608/essay/

[dreadmullet]

Though it would take 40,000 years to travel to the Alpha Centauri system using modern-day rockets, future means of propulsion might one day take probes to the distant world.

That's the most depressing thing I've heard in a while.

Also, yes, the chances of finding similar life around Alpha Centauri is hilariously low. With astronomy findings like this, we learn more about how planets form and what kind of planets exist, and much less about alien life. But of course people like to discuss alien life, no matter how slim the chances are.

[LordBucket]

it would take 40,000 years to travel to the Alpha Centauri system using modern-day rockets

This problem was solved decades ago.

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

"Nuclear pulse propulsion or external pulsed plasma propulsion, is a theoretical method of spacecraft propulsion that uses nuclear explosions for thrust."

http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)

"At 0.1c, Orion thermonuclear starships would require a flight time of at least 44 years to reach Alpha Centauri, not counting time needed to reach that speed (about 36 days at constant acceleration of 1g or 9.8 m/s2). At 0.1c, an Orion starship would require 100 years to travel 10 light years. The astronomer Carl Sagan suggested that this would be an excellent use for current stockpiles of nuclear weapons."

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

"Daedalus would be constructed in Earth orbit and have an initial mass of 54,000 tonnes, including 50,000 tonnes of fuel and 500 tonnes of scientific payload. Daedalus was to be a two-stage spacecraft. The first stage would operate for two years, taking the spacecraft to 7.1% of light speed (0.071 c), and then after it was jettisoned the second stage would fire for 1.8 years, bringing the spacecraft up to about 12% of light speed (0.12 c) before being shut down for a 46-year cruise period."

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

"The journey to Alpha Centauri B orbit would take about 100 years, at an average velocity of approximately 13411 km/s, about 4.5% the speed of light, and another 4.39 years would be necessary for the data to reach Earth."

[MetalSlimeHunt]

Too bad we've never actually even come close to testing any of that. Any number of problems could arise, the least of which being that any of these would turn a spaceship in to a relativistic-kill vehicle able to destroy all life on Earth with no way to defend against it.

[LordBucket]

Any number of problems could arise

...oh, yes. Very true. Good thing our species never built aircraft. Can you imagine how awful it would be if people were to die in plane accidents? Or what if somebody were to use planes as missiles to destroy buildings? Yes, much better that we never built them.

Or what about space shuttles. Any number of them might have blown up, killing everyone aboard. Good thing we never built those either.

Too bad we've never actually even come close to testing any of that.

Yes. It is.

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

"Developed by the US Naval Academy and NASA from 1987 to 1988, Longshot was designed to be built at Space Station Freedom, the precursor to the existing International Space Station. Unlike the somewhat similar Project Daedalus, Longshot was designed solely using existing technology"

We could have. But we didn't.

It is, as you said...too bad.

[MetalSlimeHunt]

I didn't say not to build them. I am disputing your claim that we could build these already without running into some kind of showstopper issue.

And there is a legitimate safety claim that is far more valid than that of aircraft, considering that when an aircraft explodes it doesn't vaporize everything on Earth's surface.

[LordBucket]

I am disputing your claim that we could build these already without
running into some kind of showstopper issue.

Let me see if I understand you correctly. I give you links like these:

http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion
"Orion is one of very few interstellar space drives that could theoretically be constructed with available technology, as discussed in a 1968 paper, Interstellar Transport by Freeman Dyson."

http://en.wikipedia.org/wiki/Project_Longshot
"Longshot was designed solely using existing technology"

And your response to this is basically, "oh, but some sort of unexpected problem might come up. Maybe. Not that I've given any examples or sources...but, you know...it could happen."

I think you need to give a a more well thought out response if you want anyone to take you seriously.

considering that when an aircraft explodes it doesn't vaporize everything on Earth's surface.

...yeah, except that you just totally made up the "vaporize everyone on earth" part.

Here's a list of nuclear payloads that have been detonated at altitude. None of them vaporzied "everyone on earth."

Again, if you want anyone to take you seriously, you need to stop making stuff up.


If you have better alternatives, that's fine. If you accept that these solutions are valid, but would prefer that they not be implemented because of risks or consequences that you personally dislike, that's ok too.

But don't just wildly make stuff up.

[MetalSlimeHunt]

And your response to this is basically, "oh, but some sort of unexpected problem might come up. Maybe. Not that I've given any examples or sources...but, you know...it could happen."

I think you need to give a a more well thought out response if you want anyone to take you seriously.

Helloooo? We've never actually built one of these. It's great that they're supposed to be feasible and all, but you don't know that they are until one is finished and works. You're asserting the infallibility of a hypothetical thing.

...yeah, except that you just totally made up the "vaporize everyone on earth" part.

Here's a list of nuclear payloads that have been detonated at altitude. None of them vaporzied "everyone on earth."

Again, if you want anyone to take you seriously, you need to stop making stuff up.

Quit accusing me of making stuff up. I'm not talking about the possibility of a reactor explosion, or a nuke going off in the atmosphere. I'm talking about the possibility of one of these ships being brought up to max speed and piloted into Earth at .4-.10c, which would constitute a relativistic-kill vehicle and would handily destroy everything on the surface of the planet to an extent that humans would be unable to survive on Earth following such an event. As I already stated.

[10ebbor10]

And your response to this is basically, "oh, but some sort of unexpected problem might come up. Maybe. Not that I've given any examples or sources...but, you know...it could happen."

I think you need to give a a more well thought out response if you want anyone to take you seriously.

Helloooo? We've never actually built one of these. It's great that they're supposed to be feasible and all, but you don't know that they are until one is finished and works. You're asserting the infallibility of a hypothetical thing.

...yeah, except that you just totally made up the "vaporize everyone on earth" part.

Here's a list of nuclear payloads that have been detonated at altitude. None of them vaporzied "everyone on earth."

Again, if you want anyone to take you seriously, you need to stop making stuff up.

Quit accusing me of making stuff up. I'm not talking about the possibility of a reactor explosion, or a nuke going off in the atmosphere. I'm talking about the possibility of one of these ships being brought up to max speed and piloted into Earth at .4-.10c, which would constitute a relativistic-kill vehicle and would handily destroy everything on the surface of the planet to an extent that humans would be unable to survive on Earth following such an event. As I already stated.

They can't do that. The design does not include enough fuel to move away and turn around to have a sufficient run up. Besides, we're going to keep track of where these ships are(no stealth in space) and can easily intercept them. A flake of paint is enough to destroy a ship at those speeds, a shrapnel bomb would be impossible to evade and guarantee interception.

Besides, if we wanted to destroy all surface live we can already do that.
Also, the kinetic energy of a 50 kg 0.1 c impact would be more or less comparable to the Tsar bomba. Destructive, but not the end of Earth.

[MetalSlimeHunt]

They can't do that. The design does not include enough fuel to move away and turn around to have a sufficient run up.

You could do a wide slingshot around one of the Gas Giants and have a decent space between you and Earth to accelerate in. Maybe not enough to hit max speed, but enough to accelerate to a speed that we do not want anything hitting Earth at.

Besides, we're going to keep track of where these ships are(no stealth in space) and can easily intercept them. A flake of paint is enough to destroy a ship at those speeds, a shrapnel bomb would be impossible to evade and guarantee interception.

The question is whether or not we can mount such a defense against a surprise RKV attack in time. Blowing it up just outside Earth's atmosphere while all the parts are still moving at .1c would do us little good, for example. It would have to be intercepted quickly enough that Earth is missed entirely.

Besides, if we wanted to destroy all surface live we can already do that.

Right, but it would take multiple devices. No one nuke is capable of totally destroying the human race. There is a possibility that a nuclear weapon could be used without proceeding to MAD, but an RKV will have by definition doomed all humanity barring any offworld colonies.

Also, the kinetic energy of a 50 kg 0.1 c impact would be more or less comparable to the Tsar bomba. Destructive, but not the end of Earth.

Project Orion's design called for a 4000 ton ship, which would be 3,628,740 kg, or 72,574.8 Tsar Bombas impacting Earth's crust at a single point if traveling at .1c (going by your figures). As the original Tsar Bomba had it's yield halved over legitimate fears that it could blast a hole through to the mantle, I rescind my previous claim that it would just destroy the surface and am now predicting that such a force would risk compromising Earth's structural integrity. Regardless of whether it does or not however, the entire atmosphere has been blown off and humanity is extinct.

[kaijyuu]

I'm assuming we'd be pointing this thing away from earth, and not towards it, so I don't see where the fear of destroying everything is coming from...

Unless you think it'll slingshot around somehow?

[MetalSlimeHunt]

I think someone would do it intentionally.

[Duuvian]

I think someone would do it intentionally.

Hmm. It seems like you would have a process to weed out people like that from flying a spaceship capable of eliminating all life on our one planet...

Is that why I can't be an astronaut? Plus it seems you could just put a bomb on the spaceship so if the captain goes space crazy, kaboom. Unless the vehicle travels faster than whatever possible signals there are available.

[Duuvian]

I think someone would do it intentionally.

Hmm. It seems like you would have a process to weed out people like that from flying a spaceship capable of eliminating all life on our one planet...

Is that why I can't be an astronaut? Plus it seems you could just put a bomb on the spaceship so if the captain goes space crazy, kaboom. Unless the vehicle travels faster than whatever possible signals there are available.

which is impossible, since the signal will probably be travelling at light speed.

but what if someone hacks the network and set off the bomb? they'd need to ensure it's disconnected from the world. It'd need to be a closed system.

Yeah, exactly. Also I edited my previous post so I'll migrate that one to this one.

EDIT: Though there is the theory that time works differently at high speed. On that note, our sun is moving as the galaxy expands so to speak if I understand correctly. Now, if an alien sun were moving at the same speed, but if a planet were to rotate faster or slower around the solar body, would their perception of time be different? Surely this can be measured via the mars rover. Or perhaps have two identical stopwatches, or a series of them for accuracy, send half to mars and leave half on earth. Retrieve the ones from mars and see if the times match.