Expert: Philip Stahl - 1/16/2005

Question
If a space craft which was able to withstand the temperature and pressure of a travel to the edge of the universe, and sit on a barrier, could the vessel not travel at the same speed as the universe, or the speed of light?  

Answer
Hello.

First of all, it must be clarified that there is no "edge" to the universe. All current observations disclose the universe to be infinite and expanding under accelerated "inflation".

The "edge" you refer to is really the observational "edge" for a given observer. For example, since the expansion started roughly 14 billion years ago- for any given observer *anywhere in the cosmos* the observational edge for the universe is some 14 billion light years distant. But this is not the same as a literal "edge".

In other words, there is no "barrier" or any "drop off" point! If one arrived at this distant place 14 billion ly away- for example- s/he would simply observe the universe from that perspective and in that frame- and where we are now would appear to be the "edge"!

I hope this is clear.

In addition, space is cold and devoid of many particles (it is as close to a perfect vacuum as one can get).

This means the temperature - as an indicator of particle density and motion - is COLD. Thus, there are NO high temperatures to withstand. Tne same goes for pressure, since the particle density is very small - there is no pressure to overcome. (High pressures would require very high particle densities to surmount - but you'd hardly find these unless you had to travel through a star! And no proper astronaut or cosmonaut would likely do that!)

A final misconception is that one can reside or place oneself at a particular point in the universe and automatically travel at light speed. This is not so.

All our spectral observations show that different objects (e.g. quasars, galaxy clusters), at different distances, travel at different velocities. Some much slower than light speed. The observations to which I refer here are based on the "red shift" for spectral lines of the object's light spectrum.

The only thing in the cosmos - so far as we can tell - that travels at light speed (c = 300,000 km/sec) is light itself. No material particle or object can do so.