Scientists using NASA's Hubble Space Telescope have discovered that dark energy is not a new constituent of space, but rather has been present for most of the universe's history. Dark energy is a mysterious repulsive force that causes the universe to expand at an increasing rate.
Investigators used Hubble to find that dark energy was already boosting the expansion rate of the universe as long as nine billion years ago. This picture of dark energy is consistent with Albert Einstein's prediction of nearly a century ago that a repulsive form of gravity emanates from empty space.
So, that's the big cosmology news for today. It's very closely releated to what's discussed in the Beyond Einstein article of a couple of days ago.
Actually, in a way, it's kind of boring, since the findings are pretty much what "conventional wisdom" (of the last 6 or 7 years) has expected. No apple carts have been upset as a result of this. But further confirmataion of accepted theories is in its own way very important too.
The take-away is that NASA now has even better justification for the JDEM kind of mission to obtain better supernovae data in order to put tighter limits on the w parameter in the "equation of state" for dark energy.
I've written a lot about this stuff before in much more detail here, but perhaps I'll revisit that to highlight the most important ideas as they relate to the present news.
There are some presentation materials here from today's NASA press conference.
Tags: dark energy, cosmology
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