Would planets near the outer edge of our galaxy be older and more likely to have highly developed life forms?

Question

?If galaxies spiraled outward from the center during or after their formation then it seems the outer spirals would be older and have more time to develop intelligent life on the planets that orbit their stars and we should search in that direction in our quest for extraterrestrials . However, I don't know if they formed that way or if they coalesced all at once. Just looking at a picture of a galaxy gives the appearance that they are spiraling outward from the center and so could have developed at an earlier time?

Answer 1

Not necessarily.

Actually, stars near the galactic center tend to be older, while stars out in the spiral arms tend to be younger. But the stars in the disk (which astronomers call Population I) tend to have more heavy elements, which are important for life to develop, while stars in the central bulge (called Population II) are poor in heavier elements.

So the best bet for looking for life would be older stars among the generally-younger Population I, which are more likely to be in the disk.

Answer 2

Hmm-m... I am not sure that this makes much sense.

If Earth and our Sun are 30 percent of the way out on one
of the spiral arms of the Milky Way Galaxy;

And Earth is 4 Billion years old (give or take some);

And mankind on Earth has been in let's say an intelligent state
for the last 100 years or so....

How does that speak to the issue of what Earth will look like in
let's say a billion or more years? How is there any connection
between the two?

Maybe on the planets circling the stars farther out on the spiral arms life has come and gone in the blink of an eye (timewise)
if you consider 100 years of intelligent life in 4 Billion years of
existance. Consider that I am talking about intelligence as in
able to fly, serious space observation with sophisticated equipment, high achievements in math and the higher sciences, space travel, etc. I mean really, what would you think about finding primitive man on some planet more than 5 or 6 light years away? Could you even detect his existance? The closest stars to us are about 4.4 Light Years distant, right? Now really get serious and tell me how you would communicate with them over such a distance given that the message would take millions of years going there, and millions of years coming back in reply. Oh, I forgot, you need to speak his/their language also, which would be ...
what?

Answer 3

The outer fringes, where you can find globular clusters of stars, are indeed older than our sun is. Galactic formation is not all that well understood yet, but galaxies don't "spiral outward." The galactic arms are gravitational lines of force. They don't actually spin, but all the stars in the galaxy move through these areas at one time or another, and many new stars are formed inside the spiral arms due to the tidal forces of the gravity of the entire galaxy. This is why you can see the arms. It's where new, very bright stars are forming and these newborn stars trace the lines of these arms. As far as looking for ET goes, we are limited to "nearby" areas in the galaxy. Those things on the fringes of the galaxy are so far away, we couldn't detect anything with our current technology.

Answer 4

Your logic would leave one to assume that the planets closer in the spirals somehow were ejected from the center at a later date than the ones on the outer edges.

This simply is not true... think about a firecracker... does it take a few minutes for the thing to eject the contents of the wrapper all over your yard? Nope. Big bang theories suggest that every bit of matter was ejaculated all over mother space during the same time period (a very short time period)

Answer 5

The answer to this question has filled books. Some things to think about... Nearer to the center of galaxies there are many more stars. Many stars go nova eventually. With the density of stars nearer to the center, the chances of a "nearby" star exploding and emitting high levels of radiation throughout its neighborhood is higher. The levels of radiation associated with a nova could be high enough to kill higher life forms on planets in adjacent solar systems.

Also, there is a theory that most galaxies have super massive black holes at their centers. As matter falls into a black hole, it is torn apart atom by atom which releases a lot of x-rays and gamma rays. These huge levels of radiation could also negatively affect evolution on nearby worlds.

Lastly, our planet has a very large moon in proportion to the planet. The moon is large enough to cause the tides in the ocean. Some folks have theorized that life began on earth in tidal pools that were flooded at high tide and exposed to the atmosphere at low tide. This constant change from wet to dry day after day allowed the early building blocks of life to form and re-form until a stable, self-sustaining form was created and thus, life began. Without our moon this would not have been possible. (So says the theory.)

Our moon was formed when a large object struck the earth as it was cooling, shortly after its initial formation. This object struck at exactly the correct angle and velocity that the earth threw off a large chunk of itself that eventually settled into a stable orbit and condensed into our moon. This is a very special set of circumstances that, I think, is very very rare. Therefore, there probably aren't nearly as many planets with life as some people think.

Answer 6

Well its very likely that planets at the outer edge of the galaxy are older but its very difficult to predict about the life forms.
Though they r older that doesnt necessarily mean that life forms are more advanced.
The other criteria should also be satisfied for instance the presence of atmosphere ,presence of gases etc.
Another possibility is that the life forms are not developed as they are here.

Answer 7

Logical assumption, however, as yet we are unable to determine if life forms can survive extreme heat or cold, maybe there are some in the cosmos although it does seem that Earth is about the right temperature to support life. However, the number of planets similar to Earth would more than likely be infinite which conjures the thought that life does exist elsewhere!

Answer 8

That assumes an earth-like evolution of biology and intelligent life imposed on planets with different histories. There are way too many variables and assumptions here.