‘Speed of light’ compared to what? is what you need to worry about. Most things in the universe won’t be moving at the speed of light compared to you (or whatever you’re inside of), and when you run into them, you won’t last for long.
If you’re zooming past the Earth at the speed of light headed straight at the Moon, you’ve got about 1 second to enjoy that before you make a very, VERY large crater.
If you change course and head straight at a frozen tardigrade, it will make a VERY large crater in you.
To actually reach the speed of light you'd be massless, so the only damage, would be from momentum transfer, at which point your particles would be reflected or absorbed like light.
But that aside, mostly I was referring to your statement:
'Speed of Light' compared to what?
Which is really not a concern. It's the speed of light for everyone with respect to everything, or it isn't the speed of light. Like, two beams of light going in opposite directions don't see the other light beam going at 2x the speed of light, just at the speed of light with lots of time dialation.
You already knew the answer to ‘What would happen if you moved at the speed of light’ was was “To actually reach the speed of light you’d be massless.” No shit. The question was already massless.
Aside from the fact that anything with mass cannot travel at the speed of light… Lots of fun things happen as you approach the speed of light. There’s an excellent mostly-hard sci fi novel called Tau Zero that explores this concept in depth and, despite being older, is worth the read.
(1) Time dilation (the universe and you have different clocks).
(2) blueshifting of objects in front of you. At 0.95c, basically all visible starlight in front of you has been blueshifted into ionizing radiation. Fun fun.
(3) shape distortion. You become more needle-shaped – getting very long and skinny, as observed by the rest of the universe.
(4) you become a nuke. At .99c if you run into anything, your kinetic energy related explosion would be roughly 6x the Tsar Bomba (largest nuke ever detonated) for each kg of mass. Or, put another way, each kg of your mass would impact with the energy of 3kg of antimatter contacting 3kg of matter. Boom.
Sci fi always overlooks the last one. Near light speed combat is basically firing buckets of sand at planets and blowing them up.
Speaking of sci fi, Kim Stanley Robinson’s 2312 does a really good job of incorporating the existential dread and lurking horror of weaponized orbital mechanics.
The time thing is interesting, but I feel like no one talks much about the appearance of passing objects. That is, I wonder how the image of a passing celestial object might distort due to length contraction and any other effects. I’m still trying to understand that. This article seems pretty digestible, so far.
I love this line, "...is an asteroid-sized moon orbiting a few thousand miles (or kilometers) above the Martian surface..." A few thousand miles...or kilometers, we don't care, pick your favorite.
They say he can explore small caves, but wouldn’t this little guy be solar charged and they could lose him if he doesn’t have enough juice to get back to the surface?
So basically 72 flights into it’s 5 flight mission it went to far over the horizon and lost line of sight. So they have to drive over to it to re-establish communication.
They’ve done good already, they don’t need to go this hard.
They went so hard they went over the horizon and lost coms.
Because it’s autonomous it’s likely still operational, they just have to get close to it.
space.com
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