June 02, 2012
Andromeda And Milky Way To Collide In 4 Billion Years

The Hubble Space Telescope keeps on giving. Brace for impact.

The Milky Way is set to collide with its closest neighbor, the Andromeda galaxy, astronomers working with the Hubble Space Telescope said Thursday. Galactic residents need not brace for impact just yet, however: The predicted collision would take place in 4 billion years.

So imagine you live long enough to still be around when rejuvenation therapies become available. Will any rejuvenated people from the 20th or 21st century survive millions of years? Billions of years? One would have to be both very risk avoidant and very lucky to make it that long. Plus,one would need to travel in a planet spaceship between stars when Sol gets too old. How far would humanity need to travel to get to a much younger star?

During the 2 billion year collision periodour sun will be thrown further away from the galactic core.

Computer simulations derived from Hubble's data show that it will take an additional two billion years after the encounter for the interacting galaxies to completely merge under the tug of gravity and reshape into a single elliptical galaxy similar to the kind commonly seen in the local universe.

Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter. However, the stars will be thrown into different orbits around the new galactic center. Simulations show that our solar system will probably be tossed much farther from the galactic core than it is today.

I want to know whether aliens from Andromeda will use the collision as an opportunity to invade the Milky Way.

Share |      Randall Parker, 2012 June 02 09:15 PM  Space Exploration


Comments
Wolf-Dog said at June 2, 2012 9:57 PM:

Intergalactic travel, or even traveling to planets that are only a 100 light years would be very difficult if not impossible because the spaceship would almost certainly collide with small particles at very high velocities. Even if the spaceship is travelling at only 50 % of the speed of light, any collision with a tiny particle that is only a fraction of the size of a grain of sand would destroy the vehicle. It will be almost impossible to avoid such collisions when the distance is so enormous and the velocity is so high.

But if more exotic methods of space travel, such as going through wormholes, etc, becomes possible, then maybe this will change everything.

Of course, it might also be possible to travel at a much slower speed, but then it would require the crew to stay in space in cryogenic sleep for a long time. Or maybe the nation traveling in the space ship would stay in the same ship for many generations.

GaryC90503 said at June 2, 2012 10:10 PM:

The main sequence lifetime of a star is a strong function of mass, roughly m^-2.5. Also we wouldn't need to find a younger star, merely one slightly less massive, and therefor cooler, less luminous, and with a longer lifespan.

Since we are talking about a person with an expected lifespan of billions of years, what would be the threshold for a "really long trip"? Ten thousand years? Longer? If the person was susceptible to boredom, then reaching the relevant age would be unlikely.

PacRim Jim said at June 2, 2012 11:41 PM:

The collision will be in slowest motion, over hundreds of millions of years, and the stars in both galaxies are so widely dispersed that it's unlikely any will collide.
However, gravity will scatter stars in all directions while they merge. So stars and planets will be ejected into intergalactic space.
When the two supermassive blackholes at the galactic centers merge, it's advisable not to get too close to watch it.
Perhaps I should sell insurance.
Low premiums for the first two billion years.

Dragon Horse said at June 4, 2012 8:01 AM:

Wolf-Dog:

Scientist are already working on "force fields" to deflect such particles...based on bubbles of charged plasma, but any practical application is years off.

Dragon Horse said at June 4, 2012 10:19 AM:

More on the science behind the sci-fi...

http://www.treknews.net/2011/07/31/science-fiction-or-science-fact-shields-up/

Gustav said at June 4, 2012 12:12 PM:

The sun will die in about 4-5 billion years anyway. So even if we were around then, we wouldn't be around for much longer--the sun will greatly expand, engulfing Mercury and possibly Venus. It may or may not engulf the Earth. Obviously, if it engulfs the Earth, it is gone. Even if it doesn't engulf the Earth, the sun will be much hotter, making Earth uninhabitable. Then, the huge sun, will shrink again, making the Earth (if it still exists) incredibly cold.

Ken Mitchell said at June 4, 2012 12:19 PM:

SOMEBODY is thinking entirely too small. Rather than leaving the Earth to roast when the Sun expands into a red giant, why not take it with us? Take a smallish planet that we don't like too much - Mercury, perhaps - and mount giant engines on it. Make repeated passes - not particularly close! to use Mercury's to tease the Earth slightly faster, to nudge the Earth into slightly higher orbits. Larry Niven worked out the math for this YEARS ago.

The major problem won't be that stars will collide - they probably won't - but that the supermassive black holes in the centers of both galaxies will certainly merge, and I would hope that Earth will be FAR away when that happens! The gamma ray burst of two galactic mass black holes merging might sterilize the entire galaxy. BOTH of them.

KLH said at June 4, 2012 12:23 PM:

Good thing I have insurance

'nother bob said at June 4, 2012 12:27 PM:

Those damned Andromeda Galaxy Aliens! Any excuse for an an invasion! When will this madness end?

Let's not wait for them, let's go get 'em!

Mike Ferrante said at June 4, 2012 1:18 PM:

Hey! Get a lawn-chair, a six-pack, half a chicken and find a place to watch.

Stu said at June 4, 2012 1:35 PM:

There are women in my family that will worry about this.

Cappy said at June 4, 2012 3:12 PM:

It's Bush's fault

Bunny said at June 4, 2012 4:14 PM:

Stu @ 1:35 PM, June 4, 2012 wins the comment thread: "There are women in my family that will worry about this."

Same with my family. Who knows, maybe one of them will figure out a way to ensure survival for all of Earth's creatures.

WJ said at June 5, 2012 1:49 AM:

What happens to a person with a lifespan of a billion years? Does he remember his childhood, or where he went to grammar school? Does he remember the name of his mother, or what she looked like? The brain only has so much room. With present-sized brains memory begins to fade in your 30s. There has to be a reason for this. How large would it have to be to accumulate the knowledge of a billion years? Adding additional memory isn't as easy as plugging in a 50 terabyte hard drive. Physical computer memory is not the same as biological memory. Biological memory isn't just about storing words and images, but about emotional content.

We are a very long way from the sorts of rejuvenation therapies that will make longer lifespans meaningful in the way you and I want them to be. What we all want is to make our late teens/early 20s last for a few extra centuries (or longer) - phsyically, intellectually and, yes, sexually. The nearest rejuvenation technologies will extend our 70s or maybe our 60s, which is still nice, if not so great for the economy, and not nearly as much fun.

WJ said at June 5, 2012 1:49 AM:

What happens to a person with a lifespan of a billion years? Does he remember his childhood, or where he went to grammar school? Does he remember the name of his mother, or what she looked like? The brain only has so much room. With present-sized brains memory begins to fade in your 30s. There has to be a reason for this. How large would it have to be to accumulate the knowledge of a billion years? Adding additional memory isn't as easy as plugging in a 50 terabyte hard drive. Physical computer memory is not the same as biological memory. Biological memory isn't just about storing words and images, but about emotional content.

We are a very long way from the sorts of rejuvenation therapies that will make longer lifespans meaningful in the way you and I want them to be. What we all want is to make our late teens/early 20s last for a few extra centuries (or longer) - phsyically, intellectually and, yes, sexually. The nearest rejuvenation technologies will extend our 70s or maybe our 60s, which is still nice, if not so great for the economy, and not nearly as much fun.

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