to avoid address abuse, please type it yourself

the center of the universe

When first presented with the remarkable fact that all galaxies are moving away from us, and those that are twice as far away are moving twice as fast, those that are three times away three times as fast, etc., this seems obvious what it implies we are the center of the universe! The truth is - this is not the case. To see how our universe is expanding, you need to look at it from the outside.

In his book A Universe from Nothing, Lawrence M. Krauss is using a clever graphic approach. [Note: overall, I don’t like the book, but more about that in another weekly, probably.] While it is hard to stand outside a three-dimensional universe, figuratively speaking, it is easy to stand outside a two-dimensi- onal one. On the picture on the right, one such expanding universe is drawn at two times, t2 > t1, the galaxies are farther apart at t2. Now imagine that you are at the galaxy which is colored light yellow at time t2. To see how the expansion of the universe looks from your point of view, simply superimpose t2 image (right) on the t1 image (left), placing your galaxy on the top of itself, as shown below. And here it is: from your position, all other galaxies are moving away, and those that are twice as far have moved twice the distance in the same time period, those that are three times as far have moved three times the distance, etc.

It doesn’t matter what galaxy you are in. So, depend- ing upon your perspective, either every place is the center of the universe, or no place is.

 2012-05-13 

2012-05-06
2012-04-29
2012-04-22
2012-04-15
2012-04-08
2012-04-01
2012-03-25
2012-03-18
2012-03-11
2012-03-04
2012-02-26
2012-02-19
2012-02-12
2012-02-05
2012-01-29
2012-01-22
2012-01-15
2012-01-08
2012-01-01
2011-12-25
2011-12-18
2011-12-11
2011-12-04
2011-11-27
2011-11-20
2011-11-13
2011-11-06

 

previous

 

WEBSITE  EDITOR:
Krešimir J. Adamić