Interstellar travel

[Mr Whippy]

Artificial gravity seems an easy fix if you just spin your occupants around?!

On travelling interstellar, I’m sure when the time comes we’ll have no need to for the reasons we think we do now, and to travel there will be like travelling to the local shop on foot… a case of opening and closing a few doors.



The biggie is getting out into our solar system in the short term while we’re undeveloped enough to need it’s resources and safety (eggs not all in one basket)



I was considering the other day the cost of just making a huge hill so you can basically traverse “along the ground” to about 100,000ft or 200,000ft, or wherever it gets a bit tricky.

Once you can get stuff up there super cheaply (assuming you ignore initial cost), and bring stuff back down, it’d seem pretty easy to start building some big equipment for getting out and about.

Also lots of scope for a geostationary ring full of solar panels and stuff to variably shade the Earth and provide energy.

I assume someone has done some quick scribbles on this already?

Ie. Will the plate you build it on just sink/split apart under the weight?

[Gary C]

Mr Whippy said:

Artificial gravity seems an easy fix if you just spin your occupants around?!

On travelling interstellar, I’m sure when the time comes we’ll have no need to for the reasons we think we do now, and to travel there will be like travelling to the local shop on foot… a case of opening and closing a few doors.

The biggie is getting out into our solar system in the short term while we’re undeveloped enough to need it’s resources and safety (eggs not all in one basket)

I was considering the other day the cost of just making a huge hill so you can basically traverse “along the ground” to about 100,000ft or 200,000ft, or wherever it gets a bit tricky.

Once you can get stuff up there super cheaply (assuming you ignore initial cost), and bring stuff back down, it’d seem pretty easy to start building some big equipment for getting out and about.

Also lots of scope for a geostationary ring full of solar panels and stuff to variably shade the Earth and provide energy.

I assume someone has done some quick scribbles on this already?

Ie. Will the plate you build it on just sink/split apart under the weight?

Except it would require a fundamental shift in our understanding of fundamental physics and the discovery that anti hydrogen falls somewhat rules out certain 'sci fi' answers such as antigrav. We might just have to admit the reason no civilisation has knocked on our door is that for all practical purposes, we are all just stuck where we are.

[Eric Mc]

Mr Whippy said:

Artificial gravity seems an easy fix if you just spin your occupants around?!

On travelling interstellar, I’m sure when the time comes we’ll have no need to for the reasons we think we do now, and to travel there will be like travelling to the local shop on foot… a case of opening and closing a few doors.



The biggie is getting out into our solar system in the short term while we’re undeveloped enough to need it’s resources and safety (eggs not all in one basket)



I was considering the other day the cost of just making a huge hill so you can basically traverse “along the ground” to about 100,000ft or 200,000ft, or wherever it gets a bit tricky.

Once you can get stuff up there super cheaply (assuming you ignore initial cost), and bring stuff back down, it’d seem pretty easy to start building some big equipment for getting out and about.

Also lots of scope for a geostationary ring full of solar panels and stuff to variably shade the Earth and provide energy.

I assume someone has done some quick scribbles on this already?

Ie. Will the plate you build it on just sink/split apart under the weight?

So many misconceptions in one post

Spinning something does not create artificial gravity, it simulates it. What it actually creates is centrifugal/centripetal force. This can create the feel of gravity but there are a number of issues. In a space craft or space station sized object - such as the one depicted in the film "2001" or the rotating section of the Soviet spacecraft in "2010", as well as centripetal force, there will also be some coriolis force in play as well which may very well make rotating spacecraft or rotating sections of spacecraft very tricky. I would imagine that walking around inside a rotating ring or drum might well see you walking at 45 degrees to where you want to go - like being dizzy or drunk.

"I was considering the other day the cost of just making a huge hill so you can basically traverse “along the ground” to about 100,000ft or 200,000ft, or wherever it gets a bit tricky".

Altitude is not the issue when trying to achieve space travel, it's velocity. If you were able to walk to the top of a 200,000 foot hill and stepped off the top - you'd just plummet the 200,000 feet back to earth - like Joe Kittinger or Felix Baumgartner did in their high altitude parachute jumps.

To get off the earth and STAY off the earth, you need to achieve a velocity of around 17,500 mph (to orbit the earth) or 25,000 mph to get away from the earth completely. If you want to travel out of the solar system, you need to achieve solar escape velocity, which is around 37,000 mph. The two Voyager spacecraft are on a genuine interstellar journey as they have achieved solar system escape velocity.

[budgie smuggler]

Mr Whippy said:

Artificial gravity seems an easy fix if you just spin your occupants around?!

Or 'simply' accelerate at 9.8m/s constantly for one half of the journey, then flip the craft round and decelerate at 9.8m/s for the rest.

Accelerating at 1G it takes around 2 years to get to 98% light speed.

[Granadier]

My son, who's interested in space travel, mentions Dr Erik Lentz of Gottingen University, who has published papers on possible warp drives and faster-than-light travel. Most of the technicalities are beyond me, but here's a random link that begins to explain it: https://www.centauri-dreams.org/2021/03/11/ftl-tho...
Another summary here: https://www.npl.washington.edu/av/altvw209.html

Edited by Granadier on Wednesday 4th October 14:10

[deckster]

Mr Whippy said:

I was considering the other day the cost of just making a huge hill so you can basically traverse “along the ground” to about 100,000ft or 200,000ft, or wherever it gets a bit tricky.

Once you can get stuff up there super cheaply (assuming you ignore initial cost), and bring stuff back down, it’d seem pretty easy to start building some big equipment for getting out and about.

This is, broadly speaking, the thinking behind the Space Elevator, as popularised by Arthur C. Clarke. But whilst the concept is sound, the engineering remains way beyond us. But it's a good idea.

[LunarOne]

budgie smuggler said:

Mr Whippy said:

Artificial gravity seems an easy fix if you just spin your occupants around?!

Or 'simply' accelerate at 9.8m/s constantly for one half of the journey, then flip the craft round and decelerate at 9.8m/s for the rest.

Accelerating at 1G it takes around 2 years to get to 98% light speed.

And we don't have any technology that can accelerate/decelerate a spacecraft at 1G continuously over a period of even hours, let alone years.

[LunarOne]

Mr Whippy said:

Artificial gravity seems an easy fix if you just spin your occupants around?!

It doesn't work. Try throwing a ball in a straight line while you're spinning. And the effects on the inner ear which allow you to feel a sense of balance get messed up and you will start feeling motion sickness pretty quickly due to coriolis forces.

[Blackpuddin]

Mr Whippy said:

Artificial gravity seems an easy fix if you just spin your occupants around?!

On travelling interstellar, I’m sure when the time comes we’ll have no need to for the reasons we think we do now, and to travel there will be like travelling to the local shop on foot… a case of opening and closing a few doors.

AI will soon reach a point where humans will not need to 'go' anywhere, not physically at any rate. The distances involved + the frailty of the human body = never going to happen. These are the best clues we have. Exploring needn't involve physical movement.

[Eric Mc]

deckster said:

Mr Whippy said:

I was considering the other day the cost of just making a huge hill so you can basically traverse “along the ground” to about 100,000ft or 200,000ft, or wherever it gets a bit tricky.

Once you can get stuff up there super cheaply (assuming you ignore initial cost), and bring stuff back down, it’d seem pretty easy to start building some big equipment for getting out and about.

This is, broadly speaking, the thinking behind the Space Elevator, as popularised by Arthur C. Clarke. But whilst the concept is sound, the engineering remains way beyond us. But it's a good idea.

Not quite though. The way the space elevator is built is to first launch a space based terminus in the form of an earth orbiting space station i.e. orbiting the earth at the usual 17,500 mph. Once in orbit, the space station is connected to a ground station by super strong cables up and down which travel the elevators.
Apart from inventing new materials which can withstand the enormous dynamic forces acting on the cables, there are also issues around heat loads and electromagnetic effects as well. It's a very, very difficult thing to do in reality.

[Skeptisk]

Eric Mc said:

deckster said:

Mr Whippy said:

I was considering the other day the cost of just making a huge hill so you can basically traverse “along the ground” to about 100,000ft or 200,000ft, or wherever it gets a bit tricky.

Once you can get stuff up there super cheaply (assuming you ignore initial cost), and bring stuff back down, it’d seem pretty easy to start building some big equipment for getting out and about.

This is, broadly speaking, the thinking behind the Space Elevator, as popularised by Arthur C. Clarke. But whilst the concept is sound, the engineering remains way beyond us. But it's a good idea.

Not quite though. The way the space elevator is built is to first launch a space based terminus in the form of an earth orbiting space station i.e. orbiting the earth at the usual 17,500 mph. Once in orbit, the space station is connected to a ground station by super strong cables up and down which travel the elevators.
Apart from inventing new materials which can withstand the enormous dynamic forces acting on the cables, there are also issues around heat loads and electromagnetic effects as well. It's a very, very difficult thing to do in reality.

Very very difficult or impossible? Wouldn’t the space station have to be geostationary? That implies an orbit of 36000 km. I think longest cables we have made are between US and Europe (?) so you need something three or four times as long…and you have to take all the material into space…and somehow drop it down to earth, somehow keep it fixed in place then manage to send stuff up the cable.

I nice idea to chat about over a pint (like most of the other stuff about warp drives) but hardly serious engineering

[budgie smuggler]

LunarOne said:

budgie smuggler said:

Mr Whippy said:

Artificial gravity seems an easy fix if you just spin your occupants around?!

Or 'simply' accelerate at 9.8m/s constantly for one half of the journey, then flip the craft round and decelerate at 9.8m/s for the rest.

Accelerating at 1G it takes around 2 years to get to 98% light speed.

And we don't have any technology that can accelerate/decelerate a spacecraft at 1G continuously over a period of even hours, let alone years.

easy and the fuel only costs $6.4x10^21 ish

[WrekinCrew]

budgie smuggler said:

Mr Whippy said:

Artificial gravity seems an easy fix if you just spin your occupants around?!

Or 'simply' accelerate at 9.8m/s constantly for one half of the journey, then flip the craft round and decelerate at 9.8m/s for the rest.

Accelerating at 1G it takes around 2 years to get to 98% light speed.

That's the answer. You can do a round-trip to the centre of the galaxy and back in around 40 years - ship's time.

https://en.wikipedia.org/wiki/Space_travel_under_c...

[thegreenhell]

WrekinCrew said:

That's the answer. You can do a round-trip to the centre of the galaxy and back in around 40 years - ship's time.

https://en.wikipedia.org/wiki/Space_travel_under_c...

I like the understatement in this quote - A second big issue facing ships using constant acceleration for interstellar travel is colliding with matter and radiation while en route. In mid-journey any such impact will be at near light speed, so the result will be dramatic.

[LunarOne]

thegreenhell said:

WrekinCrew said:

That's the answer. You can do a round-trip to the centre of the galaxy and back in around 40 years - ship's time.

https://en.wikipedia.org/wiki/Space_travel_under_c...

I like the understatement in this quote - A second big issue facing ships using constant acceleration for interstellar travel is colliding with matter and radiation while en route. In mid-journey any such impact will be at near light speed, so the result will be dramatic.

As I said, we'll need shields and a deflector. Star Trek technology.

[Eric Mc]

Skeptisk said:

Very very difficult or impossible? Wouldn’t the space station have to be geostationary? That implies an orbit of 36000 km. I think longest cables we have made are between US and Europe (?) so you need something three or four times as long…and you have to take all the material into space…and somehow drop it down to earth, somehow keep it fixed in place then manage to send stuff up the cable.

I nice idea to chat about over a pint (like most of the other stuff about warp drives) but hardly serious engineering

You're correct - the station needs to be in a geostationary orbit i.e. at an altitude above the earth of around 27,000 miles. Literally, building a cable stretching all the way to the surface of the earth would be a very tall order.

[rustyuk]

My bet is that we crack how to digitise consciousness and send that at the speed of light before we discover how to send living matter at great speeds and distances.

[LunarOne]

Eric Mc said:

Skeptisk said:

Very very difficult or impossible? Wouldn’t the space station have to be geostationary? That implies an orbit of 36000 km. I think longest cables we have made are between US and Europe (?) so you need something three or four times as long…and you have to take all the material into space…and somehow drop it down to earth, somehow keep it fixed in place then manage to send stuff up the cable.

I nice idea to chat about over a pint (like most of the other stuff about warp drives) but hardly serious engineering

You're correct - the station needs to be in a geostationary orbit i.e. at an altitude above the earth of around 27,000 miles. Literally, building a cable stretching all the way to the surface of the earth would be a very tall order.

And the earth's axis of rotation actually wobbles about, which would mean that the point on the surface of the earth where the tether was anchored would not follow the same plane as the space station, effectively trying to pull it out of its orbit. It would be like trying to change the path of a Yoyo spun around on a string. The stresses would be unimaginable.

[Whoozit]

I found this a useful illustration of the limitations of the speed of light. The total distance travelled so far (to 2019) by humanity's radio broadcasts in the past 100+ years. Source https://www.sciencealert.com/humanity-hasn-t-reach...

[Eric Mc]

The square or the blue smudge within the square?

We've had broadcast radio since about 1900. If you include telegraph messages, we can go back to the 1840s. So you are looking at a circle around 180 or 120 light years from earth.

Aliens picking up earth TV is how the aliens found out about us in the book/movie "Contact" (written by Carl Sagan).