Space - The Final Frontier

[Totoro]

There are many challenges to space travel but propulsion is the biggest challenge.

Let's see:

• Human lifetime = 85 years.
• Max. distance = 85 lightyears / 2 (signal round-trip) = 42.5

Number of stars within 40 light-years = approx. 2.000 (according to: Stars within 50 light years). Not a lot, but still .. bound to be something interesting around. However, propulsion isn't the biggest issue? What about hitting anything at a fraction of light-speed.

The lower limit is about 4.3 light years away in 43 years = 0.1c. 30.000 km/s. Say your spacecraft weighs 100 ton. Energy = 1/2 x m x v^2

1/2 x 10^5 kg x 9x10^14 (m/s)^2 = 4.5x10^19 joules. Hiroshima was about 8 x 10^13 joules. *Boom* Even hitting a tiny rock weighing 200 grams is one hiroshima.



(unless I missed my napkin calculations?)

 

[UnrealizedPotential]

Let's see:

• Human lifetime = 85 years.
• Max. distance = 85 lightyears / 2 (signal round-trip) = 42.5

Number of stars within 40 light-years = approx. 2.000 (according to: Stars within 50 light years). Not a lot, but still .. bound to be something interesting around. However, propulsion isn't the biggest issue? What about hitting anything at a fraction of light-speed.

The lower limit is about 4.3 light years away in 43 years = 0.1c. 30.000 km/s. Say your spacecraft weighs 100 ton. Energy = 1/2 x m x v^2

1/2 x 10^5 kg x 9x10^14 (m/s)^2 = 4.5x10^19 joules. Hiroshima was about 8 x 10^13 joules. *Boom* Even hitting a tiny rock weighing 200 grams is one hiroshima.



(unless I missed my napkin calculations?)

I do think propulsion is our biggest issue. Hitting something out in space is a concern, of course. Space is so big, to us at least anyway, that traveling the distance to get to the nearest star system so far has proved elusive to us. One could argue that there are other ways we could attack the problems of space travel besides propulsion. But I ask you this? If we can't get there in a reasonable amount of time, what difference does it make if we have no concerns of hitting something at a fraction of light speed if we can't get there to begin with? I want to get there in my lifetime. Right now it doesn't look good at all. Thirty years from now we may be closer. If we can get there at slower speeds , but I am dead , should I care? Yes, I should, for future generations. But for me personally, it sucks, because I won't see it.

 

[Blue Collar Guy]

I thought this thread was about Star Trek

 

[Chuckanut]

Niels Bohr - "Anyone who is not shocked by quantum theory has not understood it.

I wonder what unknown discovery will point the way to creating a FTL drive space ship?

 

[Totoro]

But I ask you this? If we can't get there in a reasonable amount of time, what difference does it make if we have no concerns of hitting something at a fraction of light speed if we can't get there to begin with? I want to get there in my lifetime. Right now it doesn't look good at all.

I'm not disagreeing. Propulsion obviously is necessary, but I don't see a fundamental limit there. Dealing with energies emerging from such speeds however became daunting:

• Accelerating 100 tons to one-tenth of the speed of light requires at least 4.5 x 10^19 joules, at 100% efficiency
• Ionizing radiation
• Hitting stuff at nuclear bomb energies

Pretty sure we can build a reactor that pushes that hard within 30 years, probably even ten or less. I am pretty skeptical about building star trek like shields in that same time frame.


Best we can try for is launch batteries of small probes with a solar sail of somesorts, radiation harden it and hope at least one of them don't get blown to pieces along the way.

 

[Totoro]

I wonder what unknown discovery will point the way to creating a FTL drive space ship?

I don't really understand it, yet Bell's Theorem is fascinating to me, as far as I get it either:

• There are multiple realities constantly emerging and disappearing
• Stuff can interact faster than light
• There is no free will

One of them has to be true. The second one is tantalizing with regards to FTL. Maybe the first one too.

 

[Koogie]

Or it could be like the sci fi shows where somebody is sent out when they first get to a point where they can send somebody.... but technology advances and they figure out how to get there MUCH faster and low and behold the first guy finally arrives after others have been there 10 or more years....

That's pretty funny when you think about it. I'm sure these have been used as sci-fi plots as well but other possible problems that come to mind when pondering extrasolar travel include:

- the trip is so long that the communications equipment they launch with becomes obsolete back on Earth and thus no one is monitoring the announcement they make of their triumphant arrival (or of problems enroute)
- the trip is so long that telescopes and remote sensing technologies advance while they are enroute and it shows that there is nothing of worth at their destination (the destination exoplanet turns out to be uninhabitable for instance)
- the trip is so long that when they arrive Earth is no longer in a state to care about it (having been wiped out by war, disease, calamity)

 

[Chuckanut]

- the trip is so long that the communications equipment they launch with becomes obsolete back on Earth and thus no one is monitoring the announcement they make of their triumphant arrival (or of problems enroute)
- the trip is so long that telescopes and remote sensing technologies advance while they are enroute and it shows that there is nothing of worth at their destination (the destination exoplanet turns out to be uninhabitable for instance)
- the trip is so long that when they arrive Earth is no longer in a state to care about it (having been wiped out by war, disease, calamity)

No doubt about it. We need FTL drive.

 

[braumeister]

I remember the one about the multigenerational starship that was the last hope of the human race. After interminable travel and innumerable obstacles, the GGGGrandchildren of the original passengers finally reached the target system.

But it turned out to already be inhabited, and an automated station in an outer orbit detected the approaching vessel, calculated that it was on a collision course with the home planet, and casually swatted it out of existence.

 

[kombat]

That's pretty funny when you think about it. I'm sure these have been used as sci-fi plots as well but other possible problems that come to mind when pondering extrasolar travel include:

[...]
- the trip is so long that when they arrive Earth is no longer in a state to care about it (having been wiped out by war, disease, calamity)

I don't see this as a "problem" with extrasolar travel, but rather a reason for it. The Sun is going to be around for a very, very long time, but not infinity. Eventually, it will die, and we'll need to relocate or perish with it.

 

[Totoro]

That's pretty funny when you think about it. I'm sure these have been used as sci-fi plots as well but other possible problems that come to mind when pondering extrasolar travel include

One of my favorites: siblings traveling at near-light speeds at different times so their lives / ages go out of sync. E.g. one ages a year, another a decade.

 

[Texas Proud]

I don't see this as a "problem" with extrasolar travel, but rather a reason for it. The Sun is going to be around for a very, very long time, but not infinity. Eventually, it will die, and we'll need to relocate or perish with it.

We got a few billion years before that happens.... and the Earth will change drastically over those years where human life might not even exist...


Also, in a billion years I think we will have much better propulsion systems than is even envisioned now... well, not quite since I know of one show who has a blink drive where you can literally blink to any other place in the universe....

 

[Koogie]

One of my favorites: siblings traveling at near-light speeds at different times so their lives / ages go out of sync. E.g. one ages a year, another a decade.

Ha.. that is good. Your examples are much better than mine..

Forever War by Haldeman was good for this theme. As was the one water world sequence in the movie Interstellar (not a superb movie otherwise). I'm going to have to go look for others. The practical physics issues that occur when we contemplate near light speed travel are much more mind bending and entertaining than a lot of the soft sci-fi pablum out there.

 

[clifp]

NASA announced their new astronaut class today five woman and seven men, that will make you feel like a tremendous slacker.

Here is a sample Bio
Dr. Jonny Kim, 33, Lt., U.S. Navy, was born and raised in Los Angeles. He enlisted in the U.S. Navy, then trained and operated as a Navy SEAL, completing more than 100 combat operations and earning a Silver Star and Bronze Star with Valor. Afterward, he went on to complete a degree in mathematics at the University of San Diego and a doctorate of medicine at Harvard Medical School. Kim is completing his residency in emergency medicine at Massachusetts General Hospital in Boston.

Robb Kulin, 33, hails from Anchorage, Alaska. He earned a bachelor’s degree in mechanical engineering from the University of Denver before going on to complete a master’s degree in materials science and a doctorate in engineering at the University of California, San Diego. He has previous experience as an ice driller in Antarctica on the West Antarctic Ice Sheet and Taylor Glaciers, and as a commercial fisherman in Chignik, Alaska. Since 2011, Kulin has worked for SpaceX in Hawthorne, California, where he leads the Launch Chief Engineering group.

Fortunately, they aren't all really handsome or pretty just most.

 

[mpeirce]

Just watched the landing of a reused SpaceX Falcon first stage on a drone ship out in the Atlantic.

This never gets old for me. So cool.

 

[daylatedollarshort]

We went to a panel presentation last night with speakers from NASA and UC Berkeley on exoplanets. At least one of the speakers thought multi-generational spaceships would become a reality someday.

As far as life on other planets, they said if other planets were as environmentally not conscious as the people of Earth, the habital time frame for a human like existence might only be 3,000 years duration before complete collapse. Finding other habital planets is looking very promising. Most stars they've studied so far seem to have planets and of those planets the estimates are 10% to 80% may be similar to Earth. So with billions and billions of stars in the universe the possibility of life on other planets is looking pretty good even at the low end 10% odds. Unless the 3K year figure is true. Then that means out of the history of the universe humanlike life might be around for only a very short amount of time on each potentially habitable planet.

One of the audience members asked if worm holes really existed and the answer was we don't know.

 

[Chuckanut]

Just watched the landing of a reused SpaceX Falcon first stage on a drone ship out in the Atlantic.

This never gets old for me. So cool.

Yea, but as some have mentioned it's a bit off center. Not a perfect bulls-eye!

We are getting spoiled.

From what I read this landing was just within the parameters for landing a booster.

"Falcon 9 will experience its highest ever reentry force and heat in today's launch. Good chance rocket booster doesn't make it back.

Musk later tweeted that the booster came in 'toasty' - high speed, high heat, used most of the emergency crush core. They pushed this one to the limit.

 

[Koogie]

This is purely conjecture on my part but I have been reading a lot of headlines lately and I wonder if I am sensing a pattern. Do you think we are witnessing the very beginnings of another space race ? This time between the US and China ? Here is a sampling.


The Chinese space industry is buying the Soviet propulsion system designs originally intended to put humans on the Moon
How a Soviet Lander Could Help Chinese Astronauts Reach the Moon

American and Chinese aircraft could be flying 4,000 miles per hour by 2030
American and Chinese defense giants are moving quickly to reach the edge of space, aiming to launch hypersonic aircraft that can cross continents in under an hour.
American and Chinese aircraft could be flying 4,000 miles per hour by 2030 | Popular Science

Space Corps: Lawmakers Lay Groundwork for New Military Branch
The Space Corps would serve under the Department of the Air Force, similar to the Marine Corps which serves under the Department of the Navy.
Legislation for 'Space Corps' Military Branch Introduced By House Armed Services Committee

 

[Keim]

I hope so. We need something to inspire us to do great things as a nation again.

This is purely conjecture on my part but I have been reading a lot of headlines lately and I wonder if I am sensing a pattern. Do you think we are witnessing the very beginnings of another space race ? This time between the US and China ? Here is a sampling.


The Chinese space industry is buying the Soviet propulsion system designs originally intended to put humans on the Moon
How a Soviet Lander Could Help Chinese Astronauts Reach the Moon

American and Chinese aircraft could be flying 4,000 miles per hour by 2030
American and Chinese defense giants are moving quickly to reach the edge of space, aiming to launch hypersonic aircraft that can cross continents in under an hour.
American and Chinese aircraft could be flying 4,000 miles per hour by 2030 | Popular Science

Space Corps: Lawmakers Lay Groundwork for New Military Branch
The Space Corps would serve under the Department of the Air Force, similar to the Marine Corps which serves under the Department of the Navy.
Legislation for 'Space Corps' Military Branch Introduced By House Armed Services Committee

 

[rocketjockey]

Just watched the landing of a reused SpaceX Falcon first stage on a drone ship out in the Atlantic.

This never gets old for me. So cool.

I launched that 1st stage the first time out here on the West Coast. Get ready for a double header because this Sunday we are punching another one out of Vandenberg.

 

[Totoro]

So with billions and billions of stars in the universe the possibility of life on other planets is looking pretty good even at the low end 10% odds. Unless the 3K year figure is true.

Even if the odds are good and the 3K figure is false, the distances are nuts. Our galaxy alone is a 100.000 light-years across. For most intents and purposes it doesn't matter that they are out there if they aren't close enough

I'd put all our efforts into contacting and screening just the few hundreds of stars close to us. Intuitively that also could make sense: it is more likely to have another 'fine place to live' close by the only known place we know that has life.

 

[braumeister]

Even if the odds are good and the 3K figure is false, the distances are nuts. Our galaxy alone is a 100.000 light-years across. For most intents and purposes it doesn't matter that they are out there if they aren't close enough

You're absolutely right, of course. But there are still a lot of us who retain some skepticism about the absolute nature of the speed of light.

After all, it was not much more than a century ago that it was felt the speed of a horse was as fast as humans were capable of withstanding.

After Newton, we felt we had it all figured out. But the 20th century proved us wrong. Who is to say that the future won't produce another stunning insight that gives us "warp drive"?

 

[Texas Proud]

Even if the odds are good and the 3K figure is false, the distances are nuts. Our galaxy alone is a 100.000 light-years across. For most intents and purposes it doesn't matter that they are out there if they aren't close enough

I'd put all our efforts into contacting and screening just the few hundreds of stars close to us. Intuitively that also could make sense: it is more likely to have another 'fine place to live' close by the only known place we know that has life.

Yea, inside our galaxy is the best we can hope for.... I just do not see use going to another... well, another that is 'large'....

 

[daylatedollarshort]

After Newton, we felt we had it all figured out. But the 20th century proved us wrong. Who is to say that the future won't produce another stunning insight that gives us "warp drive"?

Warp drive and wormholes and we're good to go!

 

[UnrealizedPotential]

Even if the odds are good and the 3K figure is false, the distances are nuts. Our galaxy alone is a 100.000 light-years across. For most intents and purposes it doesn't matter that they are out there if they aren't close enough

I'd put all our efforts into contacting and screening just the few hundreds of stars close to us. Intuitively that also could make sense: it is more likely to have another 'fine place to live' close by the only known place we know that has life.

But what form of communication would we use? How would they understand us ? What technology could we use where they would recognize it as a form of communication? I do not have an answer for that.