3 ms·
People tend to forget how big a cubic light year is. The earth itself is only 0.02 light seconds in diameter, yielding a cube of 8000 cubic lightmilliseconds.
by zaarn 8y ago
People tend to forget how big a cubic light year is.
The earth itself is only 0.02 light seconds in diameter, yielding a cube of 8000 cubic lightmilliseconds. Compared to the 2.910^31 cubic light milliseconds in a cubic lightyear... It's a rounding error inside a rounding error.
For light seconds, you're looking at 2.910^22 (if my math isn't wrong). That's the amount of cubes fitting between earth and moon to fill a cubic light years.
Even superplanets with 15 times the size of the earth are simply dwarfed by the sheer volume of a cubic light year.
The largest stars we found measure 73 light minutes, a cubic size of 389017 cubic light minutes. How much of them fit in a cubic light year? 346 billion.
- kamaal 8y agoIf something doesn't shine already. The only way to detect its existence is to send radio waves and see if something bounces off(Like Radar). I guess the point people are trying to make here. If you can't see light coming off an object, then while traveling at interstellar speeds means it will be harder to spot objects until they get too close.
- zaarn 8y agoNot all black objects reflect radar, black holes don't reflect at all. I think if you were to encounter a black hole, esp an inactive one, in interstellar space, you'd probably just get sucked in if you didn't notice the black disk...
- kamaal 8y agoI thought black holes typically have accretion disk.
- zaarn 8y agoOnly when active and sucking in matter. If a black hole has been travelling without eating for long enough the accretion disk can disappear. If a black hole is large enough it won't form an accretion disk either as it swallows stars whole.
- hvidgaard 8y agoThat is actually scary. When you travel in interstellar space, you can only travel in directions where you can see light at all times.
- leonroy 8y agoWhich actually becomes a problem in the far future when stars have moved further away from each other in an ever expanding universe and their light output becomes increasingly dim to a space faring traveller...
- hvidgaard 8y agoWhen I think about it, maybe it isn't a problem after all. I would think that you can measure gravity and see black holes before you hit them.
- Retric 8y agoYou can still detect the bent light around it from other stars. They would be significantly more obvious than planets, and you would actually reflect a tiny fraction of radar as it gets bent around the thing.
- richmarr 8y agoJust to bring the inevitable pedantry, you'd want to consider the cross-sectional surface area rather than the volume, and hitting the gravity well of a planet may turn out to be indirectly fatal too. So while I agree it's still probably very small numbers I think you may be overcooking it.