Universe and the big bang Grandsons got me stumped
Discussion
Getting him interested in Astronomy and told him about the big bang theory where everything is flung out from a central point. and thats why
galaxies are all different distances from us ( drew a circle and used the radians and once he got that concept used a ball to show him.
He then came back yesterday and said he had been reading books and wantied to know why if the universe was expanding how can our galaxy and the Andromeda galaxy eventually collide if they are going away from one point
I told him i didn;t know and would find out.
Anyone out there explain why as i could not see any flaw in his logic or am i missing something really simple?
He is 8 so a dumbed down answer would help for now
galaxies are all different distances from us ( drew a circle and used the radians and once he got that concept used a ball to show him.
He then came back yesterday and said he had been reading books and wantied to know why if the universe was expanding how can our galaxy and the Andromeda galaxy eventually collide if they are going away from one point
I told him i didn;t know and would find out.
Anyone out there explain why as i could not see any flaw in his logic or am i missing something really simple?
He is 8 so a dumbed down answer would help for now
ALL of the galaxies are NOT moving away from each other. In fact, many are actually closing in on each other and many have collided in the past. Some can be seen colliding now.
Galaxies exist in gravitationally bound clusters and even clusters of clusters- called “superclusters”. It is these clusters and superclusters which are moving apart.
Galaxies exist in gravitationally bound clusters and even clusters of clusters- called “superclusters”. It is these clusters and superclusters which are moving apart.
Terminator X said:
Black holes pulling everything closer whilst the universe itself still expands?
TX.
I think for simplicity's sake to the 8 year old, it would be safe to set out that "despite the universe expanding, some galaxies will move in different directions to the expansion due to the attraction of the supermassive black holes at the centres of, for example, the milky way and our nearest neighbour, andromeda".TX.
(on second thoughts I would probably leave the bit out about the supermassive size of the black holes in case it freaks him out a bit)
FourWheelDrift said:
Big bang, explosion of unstable matter forming an expanding universe until gravitational forces start to bring everything back together again into one unstable mass, followed by another big bang forming a new expanding universe and repeat again.
That doesn’t explain why some galaxies approach each other.The general position is that the universe is expanding and there is, at the moment, no indication of any mechanism which can cause it to contract.
silverfoxcc said:
Getting him interested in Astronomy and told him about the big bang theory where everything is flung out from a central point. and thats why
galaxies are all different distances from us ( drew a circle and used the radians and once he got that concept used a ball to show him.
He then came back yesterday and said he had been reading books and wantied to know why if the universe was expanding how can our galaxy and the Andromeda galaxy eventually collide if they are going away from one point
I told him i didn;t know and would find out.
Anyone out there explain why as i could not see any flaw in his logic or am i missing something really simple?
He is 8 so a dumbed down answer would help for now
Answer...galaxies are all different distances from us ( drew a circle and used the radians and once he got that concept used a ball to show him.
He then came back yesterday and said he had been reading books and wantied to know why if the universe was expanding how can our galaxy and the Andromeda galaxy eventually collide if they are going away from one point
I told him i didn;t know and would find out.
Anyone out there explain why as i could not see any flaw in his logic or am i missing something really simple?
He is 8 so a dumbed down answer would help for now
When two people face each other and one of them farts in the opposite direction the other person will still smell it.
tight fart said:
By the time he’s our age the Big Bang theory will also be a thing of the past.
The TV show maybe. The Big Bang model has some pretty compelling observational evidence to back up the theory - cosmic microwave background radiation and galactic red shift for example. You might hope that in 50 years we'll have resolved the current cosmological crisis revolving around different models of precisely how fast the universe is expanding though.As regards reconciling cosmic expansion with galactic collision, consider two ants on the surface of an inflating balloon with a short pre-tensioned piece of elastic between them - the inflation of the balloon, which would tend to move them apart, is relatively slow but the tension in the elastic is strong enough to drag them together more quickly than the expansion of the balloon can pull them apart.
silverfoxcc said:
He then came back yesterday and said he had been reading books and wantied to know why if the universe was expanding how can our galaxy and the Andromeda galaxy eventually collide if they are going away from one point
How about an analogy. Remove a dimension from "space" and think of it like the surface of a a bubble.https://youtu.be/sTH3zzQwPI4
Swirling variations of the 2D surface of a bubble can move and collide while the bubble itself is still expanding.
Swirling variations of the 3D "surface" of space can move and collide while space itself is still expanding.
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