Milky Way galaxy heading for a collision – in about 4,000,000,000 years!

As with huge numbers of others who come to this blog, the night sky has always been of incredible fascination to me.  To reinforce that fact, one of the favourite posts on Learning from Dogs for the last three years has been The night sky above published back on the 27th March, 2011.  If you haven’t read it, do pop across and do so as the title is misleading in terms of the post.

Thus it was unavoidable not to pick up on an item recently referred to by Naked Capitalism that had been published by the EarthSky blog.  This particular item was called Night sky as Milky Way and Andromeda galaxies merge.  It began thus:

As seen on Cosmos … the collision and merger between our Milky Way galaxy and the nearby Andromeda galaxy 4 billion years from now.

The video below illustrates what NASA scientists announced in 2012 – and what the Cosmos TV series featured in 2014 – that the nearby Andromeda galaxy will collide and merge with our Milky Way galaxy 4 billion years from now. The video (from the Hubble Space Telescope news center) is from a series of photo illustrations, showing the predicted merger between our two titan spiral galaxies, as seen in Earth’s sky. Will Earth as a planet survive long enough to see this? A word about that at the end of this post.

The video lost a lot for me by not carrying a commentary.  But no problem as one was found that did have a ‘voice-over’.  However, the article photographs were stunning.  For example:

A description of what’s happening in the images above:

First Row, Left: Present day.
First Row, Right: In 2 billion years the disk of the approaching Andromeda galaxy is noticeably larger.
Second Row, Left: In 3.75 billion years Andromeda fills the field of view.
Second Row, Right: In 3.85 billion years the sky is ablaze with new star formation.
Third Row, Left: In 3.9 billion years, star formation continues.
Third Row, Right: In 4 billion years Andromeda is tidally stretched and the Milky Way becomes warped.
Fourth Row, Left: In 5.1 billion years the cores of the Milky Way and Andromeda appear as a pair of bright lobes.
Fourth Row, Right: In 7 billion years the merged galaxies form a huge elliptical galaxy, its bright core dominating the nighttime sky.

The sequence is inspired by dynamical computer modeling of the inevitable future collision between the two galaxies.

Further on in the article one reads:

Will Earth survive long enough to see this merger of galaxies, as depicted in the video above? Earth as a planet might, but life on Earth – probably not. Astronomers say that the luminosity, or intrinsic brightness, of our sun will steadily increase over the next 4 billion years. As the sun’s luminosity increases, the amount of solar radiation reaching the Earth will also increase. It’s possible that – around 4 billion years from now – the increase in the Earth’s surface temperature will cause a runaway greenhouse effect, perhaps similar to that going on now on the planet next door, Venus, whose surface is hot enough to melt lead. No one expects to find life on Venus. Likewise, life on Earth will probably not exist 4 billion years from now. What’s more, our sun is expected to become a red giant star eventually. A probable fate of the Earth is absorption by the sun in about 7.5 billion years, after our sun has entered the red giant phase and expanded to cross Earth’s current orbit.

Anyhow, I mentioned that I found a better video on YouTube than the one included in the original article, and that is now presented.

Rather puts the grunt and grind of daily life into perspective! 😉

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