Castanet

I think some are already here, like the Japanese murder bees.

Size of the ship isn't really a barrier for interstellar travel, rather it's the sheer distances.

Let's look at you example: Even at 5% speed of light, the nearest solar system is still 4.37 light years away resulting in a 1-way trip of 87.4 years.

It’ll still be difficult to survive without gravity. Your body will wither away after a few years. So gotta take a big spinny-spaceship. As for brain-size, the bigger the brain, the bigger the appreciation for what you’re doing ;-)

Sadly, with the technology available today interstellar travel is mostly a pipe dream. Even if we were able to travel at the speed of light, travelling between solar systems is "impractical" IE 4.37 years 1-way to the closest system. 1000 years 1-way to the closest black hole. Travelling at anything higher than a small fraction of light speed is currently outside of our reach, yet to practically travel the stars we need to find a way to travel at multiple orders of light speed.

I say mostly, because I do think the idea of a very large multi-generational ship (in flight for 100+ years at a time) is within humanity's reach. BUT, it would easily represent the largest and most complex item that humanity has ever built. It would take decades to build, Trillions of dollars, and collaboration on a global scale. But I do think we could do it if we (by we I mean all of humanity) really wanted it.

A pipe dream... or.... a wormhole dream. Tyler, I think you’re on to something! In fact, instead of making us go the speed of light, make light go the speed of us! That’ll fix its little red wagon. lol. Anyways, we don’t even have an idea of where to go yet. We think we can casually travel from point A to B to C and dozens of other places when in reality we cant even go from point A to point A.

I’m afraid nothing of the such will happen in my lifetime. A large multigenerational ship will take literally multi generations to build as well. It too will be a spinny thing, lol.

oldtrucker wrote:

Jlabute wrote:It’ll still be difficult to survive without gravity. Your body will wither away after a few years. So gotta take a big spinny-spaceship. As for brain-size, the bigger the brain, the bigger the appreciation for what you’re doing ;-)

I think that if we had the tech to put together not a H3 fusion drive ( that would be low tech) , but a antimatter drive, then we would probably be able to find and manipulate gravitons, and create artificial gravity.
Antimatter....One drop of antiwater hitting water would result in about 10 kt of energy, so storing any real amount would require storing it on the far side of the moon for safety. What happens when the power goes out on the magnetic containment field storing a beer bottle sized amount of antimatter? The crater would be 3 miles across.

Although a step forward from where we are now, thrust from nuclear or chemical energy likely won’t do it IMO. Ion propulsion is in the same boat. Suggestions towards bending space I can only imagine would require enormous amounts of energy... more than what we can put in to space. I wonder what the most promising technology will be. We theorize about gravitons and the ability to control them, although we’ve never seen one nor understand what could control them. It’s been suggested they also travel at the speed of light ... although maybe an artificial gravitational environment can be made? We will need a compact means to do that in a specific area or pattern. Not in our lifetime I bet. We can generate gravitons already just by having mass, we can’t detect them though.

The fastest probe we’ve accomplished so far, aided by the suns gravitational pull, is 692,000 km/h. Pretty zippy at 192km/s which is 0.00064C.

oldtrucker wrote:
I think that if we had the tech to put together not a H3 fusion drive ( that would be low tech) , but a antimatter drive, then we would probably be able to find and manipulate gravitons, and create artificial gravity.
Antimatter....One drop of antiwater hitting water would result in about 10 kt of energy, so storing any real amount would require storing it on the far side of the moon for safety. What happens when the power goes out on the magnetic containment field storing a beer bottle sized amount of antimatter? The crater would be 3 miles across.

If we come up with a drive system powerful enough, we don't need artificial gravity.

Accelerate the ship at a constant 1G until the 1/2 way point, then spin 180* and decelerate at 1G for the last 1/2 of the trip. Even when constantly accelerating/decelerating at 1G It's still a very long trip tho :(

oldtrucker wrote: I looked up a few websites for that and in general it appears it would take roughly 1 year at 1 g to reach 90%C- ish. When it gets to 99.999% I don't know if it even makes sense at 1 g because at those fine decimal points it's so close to C...yet so far. At 99.999%C at trip to a system 100 light years away takes 101 earth years. Just under 6 months (not including acceleration) ship time according to a online time dilation calculator. So for those last percentage points ,could something still accelerate at 1 g? Is it relative? No.That's a fiziks question that I think is beyond my math skills.

Good point. You may want to maintain the acceleration past 90% just to maintain a false gravity. I guess it'll depend on the cost and availability of fuel for this hypothetical engine. As we approach C we run into relativistic effects that may prevent us from doing so then. The energy required to maintain 1g acceleration is on a logarithmic scale/relationship.
Kinetic Energy (KE) = 1/2 * Mass * speed squared KE=0.5mv^2
It's the Speed squared (v^2) that results in the logarithmic relationship between energy and speed. It's also the reason why it takes 4x longer to stop your car when you double your speed.

As speed increases, the energy required to maintain that same acceleration increases at the square of speed. So long story short - an engine that can maintain 1g of acceleration while travelling at 0.9C would need to output a tremendous amount of energy. Energy that we cannot even fathom - in the case of a large spaceship we're talking about "comparable to total output of a star" levels of energy. An engine powerful enough to supply all of the electricity used on earth wouldn't even come close to being powerful enough. You get the idea...

Don't forget you have to slow down as well so you can only accelerate half way then you need to turn around and decelerate.

He didn't forget. Check a few posts up.

The whole idea of interstellar flight occurring before any human currently alive passes on is ridiculous.
There is NO realistic way to get to neighboring stars with current understanding of physics AND engineering. Just a lot of science fiction with no real world solutions for solving major engineering roadblocks.

I may live long enough to see the first humans attempt a trip to Mars. I hope to still have my cognitive ability to even notice that it's happening. Until then I revel in the current missions and soon to be launched missions of robotic and human spaceflight.
Perseverance (with Ingenuity) , Parker, Europa Clipper etc.

Also the money required is beyond anything we can imagine. Even the Europa Clipper just had a cut to a key instrument due to cost. Replaced with a cheaper, less detailed instrument. Science community is a bit miffed to say the least.

Dream all you want but it is just that.

JagXKR wrote: The whole idea of interstellar flight occurring before any human currently alive passes on is ridiculous.
There is NO realistic way to get to neighboring stars with current understanding of physics AND engineering. Just a lot of science fiction with no real world solutions for solving major engineering roadblocks.

That is absolutely true. Not in our lifetime with our current knowledge and understanding. Still, if we look at the rate of advancement in human knowledge, we can only imagine the discoveries and the changes we will see in the next fifty to one hundred years. There are all kinds of possibilities out of the field of quantum physics, and scientists are studying the possibility of using gravity waves. Ya, this will be like nothing we know of to date but imagine showing some cowboy how you do your banking on your iphone. I also hope I’m still alive to watch humanity’s first attempt of humans to reach Mars. This is very exciting stuff, and while few of us could predict how long it will take for us to start travelling out of our solar system, I still predict it will be within the next hundred years. We can only imaging how different everything will be by then.

According to the science show “idiocracy”, all scientific advancements in the future will be in the area of hair-loss and penis enlargement.

To add to the artificial gravity, you could accelerate at 1g to 0.99c, then accelerate at -1g to 0.95c, etc.

I don’t think we will have anything near 10%c for 200 years until we leave the space snuff era.

Jlabute wrote:According to the science show “idiocracy”, all scientific advancements in the future will be in the area of hair-loss and penis enlargement.

VERY astute observation!


As for OldTrucker...

Your Moniker belies the level of thought about physics you engender (no insult intended to truckers).

Thanks folks for running with an interesting thread at this lousy time. Was a good read that induced a few thoughts I might comment on later. But for now I have to say thanks for engaging me.

Jlabute wrote:According to the science show “idiocracy”, all scientific advancements in the future will be in the area of hair-loss and penis enlargement.

I love that movie. I do think it was released about a decade too soon. Right about the time Trump became president would have been perfect ;)


Good idea around continuously accelerating/decelerating as you approach maximum velocity. If you have the fuel to do this, it would be a viable way to sustain an artificial gravity without greatly lengthening the trip.