DISCOVER ON SPACE DISCOVERIES

The June, 2005 issue of Discover magazine includes a series of comments from noted astronomers on the most important discoveries of the last 25 years, with hints of what are likely to be the most interesting issues in the years to come.

Some of the items that were prominent in their comments are the following:

Planets around other stars -- The discovery of more and more planets around nearby stars. There is a wide variety of conditions on these planets, suggesting a vast diversity of possibilities in the universe for large, non-luminous objects orbiting stars.

The diversity of conditions on objects in our solar system -- The discovery of the possibility of water at some time in Mars' past, "volcanos on Io, ... oceans inside Europa, a complex... Titan, and ... a youthful surface on Triton," are among the wonders.

Progress toward discovering extraterrestrial life -- The two items above bring us closer to what most astronomers suspect: that life will be found on other bodies in the universe.

(Editorial note: For all those who fervently hope to encounter intelligent extraterrestrial life, it should be noted that on earth, no type of life has successfully communicated very well with any very different form of life; and in many cases one life form will eat another, or kill it as part of its reproductive process. Finding extraterrestrial life could be very dangerous. Actually, we might not even realize we have encountered it, since it could be very, very different from anything we could recognize. Indeed, for example, one could imagine a form of life whose characteristic is to scan for signs of electromagnetic radiation coming from space -- a sign that life has evolved somewhere, radiating energy -- and hone in on it -- that is, us -- to scavenge for food.)

Dark energy -- There appears to be some force, different from the ones (strong, weak, electromagnetic, and gravitational forces) we are familiar with, that is pushing the universe to expand. (It could possibly be described as "anti-gravity", I suppose, though its nature is not yet understood at all.)

Dark matter -- It appears that the stuff we are made of, the stuff that interacts in the familiar way with the familiar forces mentioned above, is only a small fraction (maybe 4%) of all matter. Although it is called "dark matter," it is better described as transparent. It does not absorb light (as something dark would do). Rather, everything we know just passes right through "dark" matter. It is really quite amazing that 96% of the matter in the universe -- presumably all around us -- is stuff we know almost nothing about.