New Study Shows Universe Still Expanding On Schedule 173
The Bad Astronomer writes "A century ago, astronomers (including Edwin Hubble) discovered the Universe was expanding. Using the same methods — but this time with observations from an orbiting infrared space telescope — a new study confirms this expansion, and nails the rate with higher precision than done before. If you're curious, the expansion rate found was 74.3 +/- 2.1 kilometers per second per megaparsec — almost precisely in line with previous measurements."
8 year old's question (Score:5, Insightful)
Re:Obligatory Spelling Comment (Score:3, Insightful)
that is an impressive way to misspell 'messureents'
Wrong. 'messureents' is how you spell 'messureents'.
Re:8 year old's question (Score:5, Insightful)
Not to be pedantic (Score:3, Insightful)
The visible part of the universe is expanding. We have no clue what's happening to the infinitely large part we can't see.
Re:Not to be pedantic (Score:5, Insightful)
Well, to be pedantic, its a stretch to say "we have no clue". We can make some pretty damned good guesses.
Re:Obligatory Spelling Comment (Score:4, Insightful)
Not to be pedantic
Sorry to be pedantic, but you are being pedantic.
Re:8 year old's question (Score:4, Insightful)
Correction: There is no space and time that we can determine with any certainty outside our physical universe.
This is imprecise at best. There is no "outside our physical universe", because dimensions becomes meaningless at the border of the universe, so there is nowhere "outside" for other universes to be. If they exist, they don't exist "outside" our universe, at least not in a dimensional sense.
As for time, that is a purely local phenomenon, and we can not determine it even inside our universe, except right here. Every "here" will have its own rate of time.
Re:8 year old's question (Score:4, Insightful)
The problem with what you're saying is the word "into". It still suggests that there is some medium into which the universe expands. It's another form of the famous Hawking problem "What's north of the north pole?" If there is nothing, then the universe is not expanding into it. It is simply expanding.
As much as anything, it is a problem that while expressable mathematically, is, at least to most peoples' brains (mine included) something impossible to imagine. It is just another way in which our common every day perceptions of the world around us don't model every aspect of reality well.
Re:Units (Score:3, Insightful)
I think you got your final result messed up:
(74.3 km / s / mparsec) * (1 / 3x10^19 mparsec / km) = 74.3 ? / s * 3.3x10^-20 ~ 2.4 x 10^-18 cycles per second ~ 403768506056527590 seconds per cycle ~ 12.7 billion years per cycle.
It helps to actually include the units in your math as "unsolvable variables" that cancel each other out in your conversions. It's a fairly easy way to make sure the math comes out correct. Granted, this extremely rough number is kinda interesting because it is less than 10% off from the age of the universe. May mean absolutely nothing though.
Re:The Universe has no center (Score:3, Insightful)
The center of the observable universe is exactly where I am at this moment. Beyond the observable universe, we have no idea, so we might as well assume that the center of the universe is the same as the observable universe. Me.