5/5 New theories about the expanding universe!
  by Wayne C. Rogers (Las Vegas, Nevada United States)
Before Albert Einstein died, he expressed a belief that there was a mysterious energy in the universe that held it together, yet couldn't be seen. He had no proof. In time, however, he came to believe that this thought was a blunder on his part. Now, as it turns out, he may have been right after all. This mysterious energy is known as Dark Energy and certain scientists believe that it occupies at least two-thirds of the known universe with Dark Matter filling most of the last third. Matter, as we know it, only occupies about five percent of the universe. This is part of what the NOVA espisode, Runaway Universe, deals with. There's also the race between two rival astronomy teams, each seeking to find evidence which shows that the expansion of the universe is not slowing down, but rather speeding up. Each team is able to gather the necessary proof for this new theory by observing certain types of exploding stars and the expanding heat and gases that erupt from them. Ten years ago, it seems that almost everyone thought the universe was going to stop expanding and that all the galaxies would eventually be drawn together for a gigantic implosion. Now, it looks as though that particular theory was wrong. What is the force that's causing the universe's expansion to accelerate? This is where the theory of Dark Energy may come into play. A number of today's scientists believe that Dark Engergy counteracts gravity. Rather than gravity pulling all of the galaxies together into one massive clump, Dark Energy may be keeping them apart while at the same time propelling them forward through infinite space and time. As well as discussing these new ideas, the Runaway Universe also has some breathtaking imagery of super novas and gaseous nebulae and spiral galaxies that were taken by the Hubble Space telecope and a much newer scope that enables scientists to see futher into darkness of our universe. If only I was eighteen years old, instead of fifty-six. The next fifty years are going to be astounding for astronomers as new knowledge and insight comes about, especially when we finally put a man on Mars. I wish I could be here for that moment.

4/5 a new and very interesting view of the cosmos
  by Matthew the Raven (Wisconsin)
This DVD presented a interesting information that really challenges older views of the universe. NOVA is generally excellent at making complex scientific principles accessible to the non-scientist, and this episode definitely did not disappoint. The questions raised by the possibility of an ever-expanding universe are endless, and it makes me realize just how much we don't know. Yet, everything was easy to understand and presented in a very interesting manner through the interviews with scientists and footage of their work. This is definitely a good DVD for folks interested in physics.

5/5 Excellent progress report
  by rockdoc (Bloomington, IL USA)
This program is a few years old now, but the gist of it remains true. We live in a time when astronomers are coming to terms with the fact that we simply do not know the nature of most of the material in the Universe. The show tells the story of how astronomers use supernovae to determine the rate of expansion of the Universe, and whether it will continue forever. The people involved are the best in the business, and most of them are engaging and even fun to watch. I've used this show many times in an astronomy class for non-scientists and they love it.

4/5 Runaway Universe (2000)-Makes you wonder how much we really understand!
  by Keith Mirenberg (www.spaceanimations.org)
Runaway Universe (2000) was a was very interesting four star DVD. It discussed the reasons astronomers are trying to determine just what dark matter and dark energy really are. After watching this DVD I was fairly certain these may as well be called virtual matter and virtual energy because we can't directly see either one and have only coined these terms as an "ad-hoc" way of explaining the observed motions of everything visible in the universe.

Excuse me for being a little disappointed (not in the DVD, but in the state of our understanding), but the search for dark matter sounds to me like the outdated search for "the ether", a prior "virtual medium" believed to occupy all space and through which light waves were believed to travel just as sound travels through the air. To quote my old physics professor, "ether there is, or there isn't". Observations and Einstein have proven the ether to be a fiction. There is no ether, no ether drag, and I am not certain there is dark matter or energy as well.

Still, we search for the presence of dark matter and the even more mysterious dark energy. Dark matter is currently used to explain the vast majority of the gravitating matter that we can't see (invisible!), which in turn is used to rationalize the observed motion of galaxies (and the like) which Newton's laws (with modification for Einstein's laws) require to work. There are other effects like gravitational lensing which have been assumed to be due to dark matter. Still, we have yet to directly observe dark matter. See Wikipedia for better explinations of dark matter and energy.

More mysterious, dark energy (or vacuum energy) permeating all of space would be used to explain the currently observed accelerating expansion of the universe. Now I love Einstein as much as the next guy, but everyone quotes Einstein's cosmological constant as being "correct", or at least on the correct track. As physicists admit, the cosmological constant was a fudge factor computed to result in a static universe, and not an expanding one. It provided an anti-gravity type force which was mathematically assumed to permeate all space and provide the necessary repulsive force to produce (Einstein's assumed) static universe against the attracting force of gravity. Einstein was the first to admit that he had no idea what the cosmological constant was.

Einstein was correct to say this was his "biggest blunder" when Hubble observed the red shift and an actually expanding universe. Nothing succeeds like success, and astronomers now say Einstein's blunder was actually one of his biggest successes. True, it provided a repulsive force assumed to occupy all space, and simply not large enough in magnitude to produce the measured acceleration of the universe. But we have just replaced one unknown with another. All that really seems to exist are our steadily improving measurements, and our growing comprehension of how much we don't fully understand. There are competing theories but we need more Hubble observations, experiments with particle accelerators and much more basic research. There is still the Pioneer X anomaly to be reckoned with and many other space based observations and anomalies (just as soon as the recession is over).

The latest findings on dark matter and energy should be available on the web.


5/5 One of the better science naratives for TV
  by R. Bagula (Lakeside, Ca United States)
In the mid-80's Hawking announced that science was nearly over:
that we had discovered everything and made math of it.
The astrophysics people in testing if the universe was slowing down, using type one supernovas as mile posts, found that the universe was actually accelerating in the expansion that they measured by red shifts.
Probably one of the most important discoveries of recent time
and since we haven't a clue what kind of energy exactly dark energy is
or what much of the dark matter is like,
it will involve new mathematics as well.