cornucopiaofmadness asked:

Why can radio and microwaves travel through space but sound can't?

Because sound waves are vibrational waves, while radio and microwaves are electromagnetic in nature.

Sound waves require a certain density of matter in order to travel and vibrate through. That’s why sound works on earth, but that doesn’t in space. There is an abundance of free molecules to vibrate through (molecules in the air). That’s how sound works by vibrating atoms and molecules.

But in space there are so little molecules available that sound waves cannot propagate.

Why electromagnetic waves can travel through space or a vacuum is more complicated and is a bit beyond my knowledge. But the gist of it is that, its because of wave particle duality and the fact that the particle involved is a photon. And photons do not require a medium to travel through.

If any physics people can elaborate or correct me, feel free.

Artificial Gravity

Did you know it’s a thing?

Did you know there are artificial gravity chambers at carnivals?

When I was a kid there was a ride at the local theme park called the “Turkish Twist” where a bunch of people get into a circular room. The room then starts spinning.

As the spinning gets faster, you’re increasingly pressed back into the wall with more force. Once you’re essentially sticking to the wall, the floor drops away but you stay, stuck to the wall.

Since there are health issues with being in a 0 gravity environment, NASA decided to try their hand at a similar form of artificial gravity:

Gemini 11, while in orbit, tethered itself to another spacecraft and they fired their thrusters sideways, creating one giant spinning spacecraft connected in the middle by a big tether (shown above).

It worked, NASA had created a whopping 0.00015 g (which isn’t much - Earth’s surface there’s 9.81 m/s^2 (which is 1 g)). The important thing is that we now know artificial gravity works in space. The technical term for this is centrifugal force

There’s (of course) a problem. The amount of speed you’d need to spin at to generate anything useful in a spacecraft as big as Gemini 11, or even the International Space Station, would be so great that the blood would have trouble circulating to your head (it would be forced to your feet by the spinning).

The size of a spacecraft required to safely generate artificial gravity is at least the size of a football field, so until we’re able to lift such structures into orbit (or build them in orbit), we’re probably not going to see use of physics to mimic gravity. Who knows what the future holds though?

(Image credit: NASA)

Before I upload a post about where the original Martian rotational poles were located, take a look at this data and see if you can figure it out.

This is the sort of stuff NASA robots send us to work with. The colors indicate magnetized regions.

Don’t feel bad if this doesn’t mean much to you. Most researchers fail to agree on any but the most large scale trends here.

That said, I assure you there’s a lot of useful stuff going on. Mars didn’t leave us empty handed.

The killer left a trail…

(Image credit: NASA)

awaitingtherain asked:

On the topic of EM waves propagating through space: How does signal strength play a role? For instance, if a radio signal from Earth reaches a planet 100 light years away, and say it is received by some indigenous intelligent species, would there be any sort of decay in the signal that would hinder their ability to decipher it? I ask this because I have always been under the impression that clarity of signal is dependent on its strength, although I only have a limited knowledge of how they work.

That’s beyond my knowledge of physics, but it is an interesting question.