A View of Colliding Galaxies

Colliding GalaxiesSeveral powerful telescopes, including the Hubble, have managed to capture an event that occurred when the universe was half its current age: two galaxies colliding. This ancient event has been hidden to acus until now, because the galaxies were situated behind a much larger galaxy blocking our view.

However, the large galaxy in question was so big that it acts like a magnifying glass for the space behind it. This and other “lensing galaxies” are so large, they bend and distort light from smaller galaxies behind them, allowing astronomers to be able to see what would normally be obscured from view as long as the lensing galaxy and the one behind it are precisely aligned.

“These chance alignments are quite rare and tend to be hard to identify, but, recent studies have shown that by observing at far-infrared and millimeter wavelengths we can find these cases much more efficiently,” Hugo Messias of the Universidad de Concepcion n Chile and the Centro de Astronomia e Astrofisica da Universidade de Lisboa in Portugal, said in a statement.

At the end of July, astronomers found the farthest lensing galaxy yet, so distant that its light has taken 9.6 billion years to reach Earth. The magnifying properties of the galaxy allows us to compare local galaxies with much more remote ones and events that occurred when the Universe was significantly younger.

The above image was created combining multiple images from the Hubble Space Telescope and the Keck-II telescope at the Keck Observatory on Hawaii. These two galaxies, known collectively as H1429-0028, is creating more than 400 solar masses of gas into new stars each year. In comparison, the Antennae Galaxies, a similar phenomenon of colliding galaxies occurring much closer to us, is only forming stars with a total rate of 10 times the mass of the Sun.

Since the lensing galaxy is so far away, these events happened more than 9.6 billion years in the past. In real time, both the lensing galaxy and the colliding galaxies probably looks vastly different.

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