Blog Archive: June 2021

 

How we see the Universe Expansion.

As we look out into our universe we (astronomers) see billions of galaxies. A most impressive image made by the Hubble space telescope of the galaxy cluster Abell 370.  That is Abell 370 below with lots galaxies and distorted lensed background galaxies.  Everything in the image is a galaxy.   Abell 370 is xxx Mpc from Earth. z =

Distant Dusty, Star-forming Galaxy

MM J100026.36+021527.9 (a.k.a. "Mambo-9"), is a dusty, star forming galaxy formed when the universe was very young.  The galaxy is so far away that space has expanded during the time it took for light to get here. That expansion has shifted the light from the galaxy by a factor of 5.85. Light that left the galaxy in the visible spectrum (~ 500

Abell 1639 's Mass - Gravitational Lensing

In the last class of Recent Discoveries in Astronony, we discussed dark matter and in one example, the total mass of the galactic cluster Abell 1689. The total mass and hence the amount of dark matter was determined by using the lensing of distant galaxies beyond the cluster.  The question was asked how the astronomers knew the distance to

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