ask a physicist in AMA

[freyar]

It always seems like physics topics bring up a lot of questions and discussion, so I've thought for a while that it would be fun to set up a thread for questions about physics or related topics (what the process is like on the inside, what the career is like, etc). While I always have a pretty substantial workload, August looks like it will be somewhat less crazy than usual, so it seems as good a time as any to try one! Here's the plan. I am setting up a thread in the Ask Me Anything forum for your questions since the thread moderation powers there will be very helpful, and I'll do my level best to answer at least one a day. If you have more to discuss about one of my answers than a quick follow-up question, I ask up-front that you please copy the relevant bits back to a new thread here in the Miscellaneous Geek Talk forum. But I'm also totally happy if any of the other physicists here care to answer any questions.

My background, which you may know from other threads: I am a physicist who works in the broad subject of "high energy physics," which these days includes subatomic/particle physics (think Higgs boson/LHC experiment/dark matter), mathematical aspects of these types of theories, string theory, and other aspects of quantum gravity (stuff like Hawking radiation/black holes as well as non-stringy quantum gravity theories). My own work deals with particle physics models of dark matter and (separately) string theory, often with respect to extra dimensions. If I can give what I feel to be a reasonable answer, I'll tackle questions outside my own specialty, though.

In any case, please go post some questions! The AMA thread is over here.

 

[Joker]

A common trope in science fiction is using a type of propulsion which "bends" spacetime. Some have the idea that a ship could move at normal speed while contracting the space in front of it. Effectively reducing the distance it has to travel.

Is this theoretically possible (with exotic matter)?

What would happen to any objects in or near the space being contracted?

Cheers.

 

[Joker]

I got a little ahead of myself and didn´t read the last sentence. I´ll post it in the other thread.

 

[freyar]

An administrative note for the AMA: Fall term will be starting soon at my university, so that means teaching classes, attending committee meetings, and generally having more students around to ask questions, etc. That's all in all a fine thing, but it does mean I'll have less time for posting here. So, this is kind of a "last call" for new questions --- I'll try to answer everything that comes in by Weds or Thurs this week, but I can't promise to answer anything after that. When I close the thread, I'll try to leave it so people can still comment, assuming I can figure out the administrative features.