Space Astronomy and Time Astronomy

From Mica

Space Astronomy and Time Astronomy

An open discussion led by Piet Hut and Rob Knop

Saturday, February 20, 10:00AM PST

Held at the MICA Large Amphitheater

Overview

Traditionally, physics was divided into theory and experiment, and astronomy into theory and observation. Nowadays, however, theorists have turned into a virtual kind of observers, in that they observe the results of their detailed computer simulations, in which they speed up time, simulating billions of years in a matter of hours or days. While observers use telescopes to bridge the vast spatial distances in the universe, theorists use computers to bridge the equally vast temporal distances. Perhaps the two types of astronomers nowadays could be called `space astronomers' and `time astronomers' instead of observers and theorists.

However, the situation is more complicated. For one thing, the space astronomers also look back in time; they are taking snapshots along the past lightcone; and time astronomers create simulations of what happened inside the lightcone; perhaps the space astronomers could be called 3D astronomers and the time astronomers 4D astronomers? And there is of course the big differentce between space astronomers being (relatively) more dealing with the one real word and time astronomers (relatively) more with many possible virtual versions of the universe.

And finally, within the observational realm of astronomy, there is a significant shift happening, from simply charting the heavens as a mostly static object, to focusing on the changes that are happening. With faster supercomputers and superb detectors, it is now becoming possible to observe the whole sky many times a year, and before too long even on a daily basis. With the time element added, even to observations, a whole new window on the universe is opening up, from a detailed census of variable atsrs and asteroids and comets to explosive phenomena on all scales, out to the highest redshifts measured so far.

Note: the session will start off with Piet/Pema and Rob/Prospero discussion these space and time issues for about 15 or 20 minutes, after which they will open the floor so that everybody can join in.

Media

(There were no slides.)

Audio Recording

Note: Piet's audio is distorted for about a minute in the first 5 minutes, but is fine after that. Also, Rob's audio cut out briefly and that gap of silence was removed (so if it seems like he changes topic suddenly at the start, you know why).