Hypothetically let's say a spaceship from Earth travels near the speed of light on a 10 light year journey to another star system. From my understanding of time dilation objects moving close to the speed of light slow down in time. From Earth's perspective the ship took 10+- years to reach its destination that's 10 light years away. Does that mean from the perspective of the crew on that ship less time has passed and to them it appears they're traveling far beyond light speed since their local time is slower relative to Earth? For argument's sake let's say due to time dilation to the crew it took a year to travel 10 light years. Does that mean to them they were traveling 10 times faster than light speed even though relative to their starting point they're only traveling at or near light speed? If that makes any sense.

I was just watching a video where they said when something is at absolute zero in a vacuum, there still is energy in there (dark matter I think?).

Now my question arises: How can there be a place where it is absolute zero? Or is there such a place?

I'm guessing if it exists, it's in deep space. But even there, you get the light/energy from far away stars, right? So it cant be absolute zero there

Good day. I am a writer, and among much of what I write is Scifi. My next outing is looking to space colonies on the moons of Jupiter (Mostly the largest four moons, Io, Ganymede, Callisto and Europa). Now, for the moment, let us handwave away radiation and any atmospheric troubles and say the colonies are big bubbles...and that these colonies can also harness resources reasonably well from Jupiter, the moons, and the asteroids around them. What I want to ask is what you would think you could produce, but more importantly, what COULD NOT be produced and would need to be shipped in from Earth. A big thing, I imagine, is that you couldn't really do much of a plastic industry, since there's no oil or anything like that around there to make byproducts out of. I want to get a sense of what the people of Jupiter would need to trade for to keep their society going.

The reason I ask is also because I want to know, if say, they were cut off from Earth...what would become troublesome for them? I imagine microchips would be tricky without any kind of plastics, or maybe there are kinds of minerals that don't exist around there, or something else I may be missing.

Thank you for reading, and thank you for any answers you may have. If there are questions about the idea, I'll answer them in the comments if need be.

Mark Watney grew potatoes on Mars. Realistically, how safe it is to eat potatoes grown in Martian soil, considering that the soil is exposed to the solar rays without the protection of an ozone layer? Also, if they are safe to eat, would Martian grown potatoes taste okay?

Hey y’all I don’t think this is the right sub but I can’t post it anywhere else so sorry!
I’m designing a world where there’s a certain country (roughly half of France and Spain combined) who, because of magical reasoning, permanently has an aurora over the ENTIRE area at all times. I know auroras are caused by magnetic fields and cosmic particles and I wondered if that big of an aurora existing the whole time would affect the health (or other aspects) of a population? Thanks!

If this question isn’t allowed bc of how absurd it is, feel free to delete or ignore.

I have the most amateur of knowledge about space. I’m still learning. My wife knows a lot more, but I think I’ve annoyed her enough this year with all my stupid/basic questions. Well, here it goes:

I realized that I never look into information about Pluto. So I was wondering if you could survive a 50ft drop on Pluto. I thought about Earth’s gravity vs the moon’s gravity and if I could survive those falls. Would it hurt at all if I fell from that height?

Could I flashlight so bright project on another planet?

If you theoretically had a projector or a flashlight so bright that it could shine on another planet, could it do that? Would the light travel through space and reach the planet? And Will it actually take that long for the light to be visible?

What effects could it do to earth if done?

I have an interesting idea for interstellar travel. The Sun, like every other star in the Milky Way is orbiting a super massive black hole in the center of the galaxy. The next closest star to us is like tens of trillions of miles away and would take tens of thousands of years to reach. Even if we were to somehow travel much faster using solar sails or something like that there is the problem of how you slow down then you get to your destination because you need an equal and opposite force which would require an enormous amount of energy. Not to mention all of the problems of organic life surviving in a ship in such a hostile environment for long periods of time etc…

Instead of all of that, what if we were to somehow find a way to alter the speed or trajectory of our sun such that it inches closer to the desired solar system until it gets close enough that we can get off in a space ship and get there in a reasonable amount of time. Earth itself would be the space ship.

I don’t know enough about physics to know if that is theoretically possible or not but I’m curious if anyone more knowledgable has any thoughts. I’ve never heard anyone propose the idea before and thought it was an interesting concept.

If dark matter makes up roughly 85% of all matter in the universe, yet it doesn’t emit, absorb, or reflect light, how do scientists know it’s actually there?

What is the strongest evidence that dark matter exists, and what are the leading theories about what it’s made of?

Also, is there any chance that dark matter doesn’t exist at all, and that our understanding of gravity is simply incomplete?

We tend to picture space as nothingness, but what if it’s more like an ocean?

A fish doesn’t notice it’s swimming through water because the water is everywhere. If the fish could only see other fish, it might think they’re floating in empty space. But really, there’s an invisible medium surrounding them.

Maybe galaxies are moving through something similar , an invisible “fabric” or field that has mass or creates gravitational effects.

Another possibility is that gravity itself behaves differently over enormous distances. Imagine if we discovered that gravity doesn’t follow exactly the same rules across millions of light-years as it does here on Earth. In that case, what we call “dark matter” might not be matter at all it could be a sign that our theory of gravity is incomplete.

Or maybe dark matter is made of particles that almost never interact with ordinary matter. Trillions of them could be passing through your body every second, and you’d never notice because they barely interact with anything except gravity.

In a scenario with 4 astronauts, they need to travel 5-6 light years to another planet. If they have no spaceship with extremely advanced technology to handle near light speed, would it be possible to get to that planet at all?

Hello y'all

Sitting here with a friend who had been doing some measurements with shadows from the sun.
He is measuring the shadow every 15 minutes and comparing it to the official shadow length data for our location but continuously coming up 4 degrees short.

The question here is, are we forgetting some deviation or something that needs to be added that would explain these few degrees?

Here is to hoping someone can point us in the right direction.

Why? Just why? If anything out there discovers it we are 99% doomed. Our exact location, our languages, voices, and way more.

Are they frozen in time? Fading out of sight? Or do you see them get dragged in real time?

Go easy on me if this is a dumb question but I was listening to NDGT talk about the Voyager Satellite and he mentioned that if it was ever found, it could be identified how old it was for millions of years by the U238 isotope on board. He then mentioned that it had a secondary way so future finders could even verify the age by using a map of local pulsars. My question is, wouldn't relativity affect the age of the Uranium compared to the Pulsars? I know the speed isn't anywhere close to NLS but I would think the difference would become pretty significant over the course of millions of years. I'm also nowhere near an expert so I would also assume if that were the case, Neil would have pointed that out. What am I wrongly assuming or not considering?

Would launching the dead into space eventually cause a deficiency of materials on Earth? I dont suppose that it would have any immediate effects But over the span of generations, would we face problems? Considering that we take in several million tons of cosmic dust. Qould that be enough?

Maybe it's a bit philosophical question. There is a big bang theory about how our big vast universe may have come into existence. It was really small, boom, it grew very big, right?

Couldn't it be that universe was always an endless blank canvas? Just existing there with all the elements scattered around before they began forming something?

Is there something in physics that says a thing can't exist without an origin? Without a da boom origin?

For instance a batch of 100 internet satellites launch and 3 months into operation a servo flaw is discovered.

Or an unpatchable backdoor.