Let’s Slow This Thing Down A Little Bit…

The universe that is. According to a Peter A. Milne of the University of Arizona, the standard for measuring universe acceleration, the type 1A supernova, is not quite as standard as they initially thought. There are at least two types of type 1A supernova detected in the recently accumulated data.

Apparently the trick, the key to the new data was looking at the supervovae in ultraviolet light. There is a different aspect noticed between ultraviolet and visible light. They detected this difference with data from Swift, NASA’s orbital satellite with ultraviolet detectors, and compared them to observations from Hubbles visible light observations. The difference appears to be, and I’ll quote the source, first with our old data:

“The faraway supernovae should be like the ones nearby because they look like them, but because they’re fainter than expected, it led people to conclude they’re farther away than expected, and this in turn has led to the conclusion that the universe is expanding faster than it did in the past.”

Then with the new data:

“As you’re going back in time, we see a change in the supernovae population,” he added. “The explosion has something different about it, something that doesn’t jump out at you when you look at it in optical light, but we see it in the ultraviolet.

“Since nobody realized that before, all these supernovae were thrown in the same barrel. But if you were to look at 10 of them nearby, those 10 are going to be redder on average than a sample of 10 faraway supernovae. (edit: Referring to red shift/blue shift, basically red shift means it is moving away from us and blue shift moving towards us. There are  numerical increments that determine how far away an object is based upon its brightness. Which means we were getting false assumptions because of wrongly expecting the supernovae were very similar)

The authors conclude that some of the reported acceleration of the universe can be explained by color differences between the two groups of supernovae, leaving less acceleration than initially reported. This would, in turn, require less dark energy than currently assumed.” (end quote)

What this all amounts to is, the universe while it is still expanding, may be expanding slower than we thought. They still have to crunch the numbers to see how much slower we are talking about. It also means we might get closer to understanding the amount of dark matter there is out there. As I understand it, with the previous observational data, there is too much dark matter to accurately account for. This finding could help resolve that issue. Which is cool, I’m always happy to see a missing piece of a puzzle fall into place. Especially when that piece gets us closer to understanding the things we don’t yet know. I came across this story @ Science Daily but the original source is here:

http://uanews.org/story/accelerating-universe-not-so-fast

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