Yes! Pack your bags! Blossoming planetary system strikingly similar to ours found by boffins

Re: If you leave now,

"pump up the volume"

Well, I suppose you could name the fourth rock from this new sun MARRS....

Re: Faster than light not needed?

Assuming no new technology for manipulating kinetic mass/gravity field.

We ain't doing it with rockets that's for sure.

Re: Faster than light not needed?

All that acceleration unavoidably requires energy. A lot of energy.

Yeah. Even before you reach significantly relativistic speeds, it's nasty.

I did some back-of-the-envelope calculations years ago for my brother, who was working on a medium-hard SF novel at the time. As an upper limit, we assumed the engine could do full mass conversion of its fuel, which was metallic hydrogen. Acceleration of g even well below where I had to take relativistic effects into account turned out to be crazy expensive thanks to the rocket equation (more fuel means more mass means a higher rate of fuel consumption means more fuel...).

There's a reason why SF authors like Bussard ramjets. They save carrying all that fuel.

Saying "you just have to figure out the propulsion" is like saying "it's easy to have really low consumer energy bills, we just have to figure out feasible home fusion reactors". The propulsion is the problem.

Well, that and the fact that any other planet within a reasonable distance is almost certainly to be far less pleasant to us than the least-pleasant places on Earth. Sure, it's a big universe, and if modern cosmology is correct there's a huge number of essentially Earth-identical planets out there. But the vast majority will be outside our Hubble space, so they might as well not exist; and the vast majority of the ones we could even see (if we could make out something that small, which for all but a relatively tiny sphere around Earth we can't) aren't reachable while they're viable. And finding any that do happen to be in our neighborhood at the right point in their development won't be easy.

As others have noted, an Earth-type planet has a lot of crucial ingredients. A rocky planet in the Golidilocks zone with a spinning core (to generate a magnetic field), to start with. Yeah, maybe we could find some like that with water and a reducing atmosphere that could be seeded with cyanobacteria to give it an oxygen-rich atmosphere, if we're patient, and no one has qualms about killing off most of the planet's life, if it has any. I'm not holding my breath.

Re: Faster than light not needed?

Post proof or retract.

If no one uses Windows by that point, is it secure by omission?

Re: Faster than light not needed?

"The problem is that at any point, to get 1g acceleration relative to your destination, you have to accelerate not the rest mass but the relativistic mass. As the time dilation scales with the relativistic mass factor, to get a large time dilation requires a lot of energy."

As far as I'm aware, that's a popular misconception that comes from the way that special relativity is sometimes explained to undergraduates.

If you (the observer) see a ship flying past at a relativistic velocity, it intuitively appears that it is getting heavier and heavier as its velocity approaches c, because its acceleration reduces despite it firing its engines at full power, while its momentum increases. This is what is sometimes described as relativistic mass.

Which doesn't actually exist, it's just a useful way of getting a concept across.

The ship's momentum = mass x velocity is only true when the observer and the ship have the same relative velocity - the actual value is gamma x m x v (where γ is derived from the difference in velocity between the observer and the ship and equals 1 at non-relativistic speeds), so as the ship's velocity approaches c relative to the observer, the value of γ rises exponentially above 1, and the ship's momentum (energy) can increase without its mass increasing. The γ value explains how (to the static observer) acceleration can be falling while energy input (force) is constant.

I think even Einstein used the phrase relativistic mass in trying to explain special relativity, so it's easy to see why people use it even though it causes confusion.

If a ship starts its journey with a mass of 50 tonnes (sometimes called its rest mass, though its really just its mass), the mass will still be 50 tonnes at 99.99999% of c, so to the crew onboard the acceleration will be Newtonian i.e. the ship's engines are generating a constant force and mass remains constant so they will experience constant acceleration. The crew won't experience the falling acceleration seen by the static observer due to the time dilation they are also experiencing.

So astronomical amounts of energy are not required - all you need is a propulsion system which can provide approximately 10N of force per Kg of ship's mass, and enough fuel to keep it going for a few decades.

That's all you need he said...

Re: Another Earth?

No. It all makes sense now. From time to time they send some to shove a probe up someone's arse and so far they concluded: not ripe, not ready to harvest. Phew...