MN Physicists and Philosophers, I have some questions about time travel.

[Slubberdegullion]

Watched Donnie Darko for the first time yesterday, which led to conversation with DH about the possibilities of time travel and alternate universes, which led to wakeful period at 3am with head full of questions.

Anyone here care to have a stab at answering (in a simplistic manner, I did not do very well at A-level physics) some of my questions?

here you go

science.howstuffworks.com/time-travel.htm

that wasn't me

black holes a possibility as are cosmic strings

The New Scientist of 2 weeks ago has some interesting time theories. I bought it just for that reason.

These cosmic strings, which are thinner than an atom, would generate an enormous amount of gravitational pull on any objects that pass near them. Objects attached to a cosmic string could travel at incredible speeds, and because their gravitational force distorts spacetime, they could be used for time travel. By pulling two cosmic strings close together, or one string close to a black hole, it might be possible to warp spacetime enough to create closed time-like curves.

A spacecraft could be turned into a time machine by using the gravity produced by the two cosmic strings, or the string and black hole, to propel itself into the past. To do this, it would loop around the cosmic strings. However, there is still much speculation as to whether these strings exist, and if they do, in what form. Gott himself said that in order to travel back in time even one year, it would take a loop of string that contained half the mass-energy of an entire galaxy. And, as with any time machine, you couldn't go back farther than the point at which the time machine was created.

in conclusion, possibly not

Nuclear clocks are actually called atomic clocks

I was, er, using the Hallowe'en name....

IMO the only thing that moves faster than the speed of light is a toddler 10 feet from an open pot of red paint near a new carpet.

Go on. Try it if you dare.

EP, will you come and chat with my DH? He's on a roll now and I'm nodding and pretending to understand.

maybe toddlers have their own cosmic strings...

or they can slip into a time-space continuum due to being smaller and closer to the ground

IBS

IBS, most of my job is nodding and smiling at experts telling me about stuff I don't understand

Thank you for those links Lapin and Effie.

I think I need to re read them and digest.

I now sadly have to go and deal with some more 'earthy' insolvable problems such as getting dd2 to eat her tea.

I will be back later.

tell DD2 uneaten food slips into a black hole and remerged in another time and space

that'll do her

Physics has yet to explain how the shift from standing to sitting - even when done at a snail's pace - can make the difference between a peacefully sleeping baby and a mad shrieking flailing gremlin intend on ruining your dinner.

I have been researching this for years.

and why babies always wake up just as you are reaching a crucial bit in the West Wing. Then they proceed to screech through the bits where people are talking really quietly

OK, have read links [mind aching emoticon at Lapins' with scary equations]. Have I understood it correctly that the nature of time can be altered as it passes near (or into) a body with a massive gravitational field.

So if somehow you were in a space ship and you could enter the gravitaional field of a black hole (but not get pulled in and utterly destroyed) you would experience time differently?

Not time travel as such but time would pass at a different rate for you than how we experience it on earth?

Have I almost got it?

Sounds good to me!

Excellent

So what's a worm hole then?

Ah, now it may not be physically possible to time travel, but how about mentally?

if time travel is going to be achieved at some point wouldn't the individuals who are going to achieve it have travelled to a point in time prior to now and told us all about it already?

How do you mean Desi?

(I have a question about the paradox of time travel)

Well, let's draw a line on a sheet of paper.

1750 1860 _ 1980

Now, if you were living in 1860, it would be impossible for you to see that line of time. You cannot see what is behind you, or in front of you. All you can see is 1860.

But imagine that you were a bird and you soared above the line. Now, you can see it.