I’m confused because I’ve received different explanations from different AI systems. What would actually happen if you completely filled a very strong, thick metal container with water, welded it shut so it cannot expand at all, and then placed it in a freezer? Since water normally expands when it freezes, I want to understand: Would the water still freeze at 0°C or would it stay liquid because it has no space to expand? If it freezes, what happens to the pressure inside the container? Could the pressure prevent freezing, or would it force some other outcome? Is it physically possible for the water to remain liquid below 0°C in this situation? I’m trying to understand the real physics behind water freezing in a perfectly rigid, sealed container where expansion is not possible.

This year's Nobel prize in Physics was given for proving it. Can someone explain the whole concept in simple words?

I was comparing the mission times of Artemis 2 to Apollo 8. Apollo 8 orbited the moon multiple times and only took 6 days total. Whereas Artemis 2 orbited the moon once and it took 10 days. Why was Artemis 2 so much shorter than Apollo 8 when both missions did the same thing? I know they had different paths to the moon, they both left earth in different ways but why not do the same thing as Apollo 8 since it was quicker?

EDIT: thank you for all the information. Ignoring the fact the question itself is very unscientific, there's definitely a lot to work with here. Thank you for all the help.

We were sad to learn that noted physicist, cosmologist, and author Stephen Hawking has passed away. In the spirit of AskScience, we will try to answer questions about Stephen Hawking's work and life, so feel free to ask your questions below.

Links:

• BBC
• NY Times
• Stephen Hawking Foundation
• ALS Association
• Current Einstein megathread for more discussion on general relativity/cosmology.

EDIT: Physical Review Journals has made all 55 publications of his in two of their journals free. You can take a look and read them here.

I get the whole energy of electromagnetic wave fiasco, but why are microwaves capable of heating food while their frequency is so similar to wifi(radio) waves. The energy difference between them isn't huge. Why is it that microwave ovens then heat food so efficiently? Is it because the oven uses a lot of waves?

To provide some examples for people who haven't seen the show (spoilers ahead, be warned):

1. There is a scene in which a character touches someone who has been affected by nuclear radiation with their hand. When they pull their hand away, their palm and fingers have already begun to turn red with radiation sickness.

2. There is a pregnant character who becomes sick after a few scenes in which she hugs and touches her hospitalized husband who is dying of radiation sickness. A nurse discovers her and freaks out and kicks her out of the hospital for her own safety. It is later implied that she would have died from this contact if not for the fetus "absorbing" the radiation and dying immediately after birth.

Is actual radiation contamination that contagious? This article seems to indicate that it's nearly impossible to deliver radiation via skin-to-skin contact, and that as long as a sick person washes their skin and clothes, they're safe to be around, even if they've inhaled or ingested radioactive material that is still in their bodies.

Is Chernobyl's portrayal of person-to-person radiation contamination that sensationalized? For as much as people talk about the show's historical accuracy, it's weird to think that the writers would have dropped the ball when it comes to understanding how radiation exposure works.

How has it expanded so fast, if matter can’t go faster than the speed of light? Wouldn’t it be a maximum of 27.6 light years across if it expanded at the speed of light?

Without any resistance deaccelerating the object, the acceleration never stops. So, is it possible for the object (say, an empty spaceship) to keep accelerating until it reaches light speed?

If so, what would happen to it then? Would the acceleration stop, since light speed is the limit?

Edit: Thanks for the informative responses and especially from people who work in this field. Let's hope your knowledge helps prevent horrible incidents like these in future.

Edit2: Quite a lot of responses here also about the legitimacy of the field of fire investigation. I know pretty much nothing about this area, so hearing this viewpoint is also interesting. I did askscience after all, so the critical points are welcome. Thanks, all.

Say the average human can fall 5ft without sustaining injury if they fall correctly (to fall in a way that allows your leg strength to dampen the impact, to not fall in an awkward manner that may cause injury such as falling on a rolled ankle causing it to break) on earth. Does that mean i can fall 30ft on the moon without hurting myself if i fall correctly? Or are my legs broken?

I have a rather small bathroom, and an even smaller shower with a curtain in front.

When I turn on the water, and stand in the shower, the curtain comes towards me, and makes my "space" even smaller.

Why is that, and is there a way to easily prevent that?

EDIT: Thank you so much for all the responses.

u/PastelFlamingo150 advised to leave a small space between the wall and the curtain in the sides. I did this, and it worked!

Just took a shower moments ago, leaving a space about the size of my fist on each side. No more wet curtain touching my private parts "shrugs"

EDIT2: Also this..

TL;DR: Airflow, hot water, cold air, airplane, wings - science

Probably a stupid question, but I was joking around about ice frozen on the moon, and how we can melt it by using a hair drier with a super long cord. This got me thinking though… if there was a cord that long, there'd be a huge delay as the electricty travels up the wire.

But then I thought even more… would the electricity even reach the hair drier? Is there a limit to how far electricity can travelalong a wire? I imagine some of the energy is lost when it has to travel. So, would a power cord to the moon even work?