Expert: James Gort - 6/13/2005

Question
1. What colour are the eight planets: mercury, mars, jupiter, venus, neptune, saturn, pluto, and uranus.

2. When and how do you think mankind will be extinct?

3. How did the universe and will it end?

Answer
Hello Kristine,

1.  I think the best site I can recommend is http://teacher.scholastic.com/researchtools/articlearchives/space/planets.htm

That web site has the answer to your question about planets' colors, and quite a few more answers about planets.  Hope you enjoy it!

2.  That's a very difficult question to answer.  Mankind is very adaptable, and can adapt quickly to new climates and changing conditions.  But Nature is very powerful, and no match for Mankind.  We witnessed Nature's power in the Asian tsunami (tidal wave), earthquakes, hurricanes, volcanoes, etc.  And if a large asteroid hit the earth, such climate change would result that the ability of mankind to adapt would certainly be tested.  So the answer is "nobody knows" and we cannot even give a good guess.  Nature has the power to destroy all human life, and Man has acquired that ability, too (through massive stock piles of nuclear weapons).  But Man has a powerful mind to find solutions to these threats.  I think Man will be around for a long, long time to come.

3.  Again, the answer is "nobody knows".  There are lots of theories and ideas, but none of these theories are "testable".  We can just look at how things are now, and decide what might have happened to get it here.

One theory is that all energy in the universe was bunched together (there was no such thing as matter, because the universe hadn't created it yet!), and something caused the energy to "explode".  No one can explain why the explosion might have happened.  But that explosion caused the energy to fly apart, creating matter as it did (Einstein showed that matter and energy are different forms of the same thing).  Some who believe this theory think the universe will continue expanding forever as a result of that initial explosion.  Eventually, galaxies of stars will become extremely far away, existing stars will die, and some new ones will form, but the universe will eventually "cool off" and slowly die.  Other people think the expanding universe will eventually stop expanding, and start to reverse the process - actually collapsing.  After a very long time, the universe will collapse to a small size of pure energy, and it may again explode (repeating the whole process).

Still other people think that the "Big Bang" (that I described above) never happened.  Instead, the universe always was and always will be, and new matter is being continuously created in space from a supply of energy.  No one can explain what that supply of energy is.

The correct answer may be one of those theories or something else entirely.  More ideas will come (look up "cosmology" for more ideas), and some people will say they have the answer.  But no one really has the answer, and no one probably ever will.


Hope that helps.  Keep thinking about those difficult questions.  Maybe you'll help find the answers!

Prof. James Gort