Does my mass look big in this? Roly-poly galaxy El Gordo more porky than first feared The latest data from the Hubble space telescope has shown that the furthest fattest galaxy yet spotted is 43 per cent more massive than first thought and was formed by two huge galaxies colliding. The El Gordo galaxy Galaxy with a weight problem, for astronomers at least Galactic cluster ACT-CL J0102-4915 – nicknamed El …
It's generally believed that the whole show started off with a big bang, and stuff flew apart from day 1.
Or, if you want to look at it another way, it's just space that's getting bigger each second.
Or, if you want to look at it another way, the whole notion of size might be a non-starter because there are no measuring sticks outside the universe, and words such as big and small mean diddly squat in an absolute sense.
But whichever way I look at it, I can't easily reconcile this image in my mind with the notion of massive galaxies bumping into each other. When a bomb goes off, I'd expect all the bits to fly off away from each other, not go bumping into each other.
What am I missing? I guess there has to be a simple explanation somewhere.
I don't know if the analogy holds but when a bomb goes off you don't expect the materieal to fly apart as individual atoms or molecules. What happens is the casing splits at the weakest points and the forces keeping the rest together as chunks of shrapnel is greater than the force attempting to tear it apart.
So perhaps the forces keeping areas of the universe together ish were greater than the forces trying to move them apart.
You are close. Imagine a bomb with the casing coated in bomblets, so the Big Bomb goes off launching/scattering the bomblets, these then go off sending their casings all over, some of those casings may collide.
Or Fireworks: We've all seen the ones that fan out, and then have secondary shells which them throw sparks in all directions; sometimes, those paths cross. In a firecracker as big as the universe, it is guaranteed that some embers will hit each other.
@Max_Bell
"...a big bang followed by lots of other little bangs at the periphery"
i have a horrible suspicion there's a Paris Hilton pseudo-joke-reference lurking somewhere here, but i can't quite put my, um, finger on it. Or anything else... (blush).
Yes. I know. Coat, please!
Er, gravity? The matter flying apart has mass and it is not all spread out completely uniformly. Everything with mass attracts other mass (gravity), eventually the gravitic attraction overcomes the kinetics of flying apart.
The denser more massive bits more so than the diffuse less massive bits. The dense bits collapsed to form galaxies. The galaxies then attract other galaxies nearby to form clusters, clusters attract other clusters to form super clusters.
So the galaxies in clusters are not flying away from each other but are slowly falling towards each other in various orbital trajectories. Some collide and merge in the process but all within the cluster will eventually merge into one super galaxy.
Leaves a lot of empty space between the super clusters which is where the expansion of space-time is still happening. Clear as mud?
It wasn't an explosion, it is an expansion or inflation (think of it as a balloon rather than a bomb, a word "bang" causes confusion). The rapid expansion had the side effects of forming atoms, then particles, etc.. which resulted later in planets, stars, galaxies, dust, meteors, etc.. Universe in general is still expanding. But in our tiny small fraction, which we call "observable universe" with only trillions of galaxies, the local rules apply, not the global rules of expansion.
Within these local rules, gravity plays much more important role than expansion. Due to gravity,things in space circle around other things in space, which then occasionally cause interference in their paths and galaxies collide. We will collide with Andromeda at some point, but don't fear. Galactic collisions are very slow and the space between objects is so huge, we won't notice anything.
There are also some mega events happening, like supernova explosions - formations of neutron stars and black holes, that alter the gravitational patterns of the objects, hence sometimes bringing them closer together.
Serious point here amongst the smart arse ones. If you are going to report on stories like this involving very big numbers do you think you could use exponential notation? We've probably all got our minds around the idea that a billion is more usually 10^9 rather than 10^12, but trillions and quadrillions? Much better to avoid ambiguity I would have thought.
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