Galaxies

Always cool to study Astronomy a little, I did this evening, thought I'd share =]


Galaxies

- 200 billion known Galaxies in the known universe.

- Our Galaxy, The Milky Way, 12 billion years old.(Huge disc with giant spiral arms, and a bulge in the middle)

Born in nebula's, born in clouds of dust and gas.

* Pillars of creation.
* Around many of them are planets and moons.

(We humans thought for a very long time the milky way was the only one until 1924, until Hubble found out otherwise).

He found fuzzy blobs of lights, far far away, whole cities of stars, galaxies, way beyond The Milky Way.


Random Facts

- M87, a giant elliptical galaxy, one of the oldest in the Universe, and the stars all glow gold!

- Sombrero Galaxy, has a huge glowing core, with a ring of gas and dust all around it.(Baal Galaxy?)

- Galaxies are big, really really big.


Some distances and perspective

On earth we measure distance in kilometers, in space astronomers use light years. The distance light travels in a year, which is just under 9,5 trillion kilometers.

- Our Galaxy is 100.000 light years across, which is just a small spec in the universe.

- Our nearest neighbour, Andromeda is nearly 200.000 light years across, twice the size.

- M87 is much much bigger than Andromeda, nearly 5 times as big.

- But all of these are tiny compared to IC1011, biggest galaxy ever found. 60 times larger than our Milky way.

- The first stars formed 200 million years after the Big Bang ( 13,8 billion years ago).

- Then gravity pulled them together, building the first Galaxies.


Mankind's incredible tenacity and creativity

Whatever we see in telescopes today are things that has happened millions or more years ago, because it has taken the light as long to get to us. The feint smudges, formed 1 billion years after the big bang is the furthest back Hubble can see.

Until recently, humankind made Act, a 500 meter tall telescope, and the largest in the world. Act doesn't detect visible light, it detects cosmic microwaves, from the time the Universe was a few hundred thousands year old.

It doesn't just detect early Galaxies, it can see how they grew. The footprints of all the growth, from a few hundred thousand years till now.

Letting Astronomers see how they form and evolve: Stars form cluster, forms to galaxies, which builds into clusters of galaxies which builds into super clusters of Galaxies.

- In the beginning Galaxies looked like poo, random and bulgy, now they look awesome and perfect. Gravity, gravity shapes and molds Galaxies


Unimaginable Power

- There's an unimaginable powerful and incredible destructive source of gravity at the heart of most Galaxies. And there's one at the deep center of our own milky way.


- For years scientists wondered what could be powerful enough to change how a Galaxy behave, and then they found out.... A black hole, not just any kind, a super massive black hole.

* It eats gas and stars, but sometimes black holes consumes too quickly, and what they are consuming are dispatched back into space in beams of pure energy.

* This is called Quasar, when they find one, they know the center has a Super massive black hole.

- The black hole in the center out of Galaxy is gigantic, 24 million kilometers across.

* Even though, Earth is in absolute no danger, since Earth is 25.000 light years away (trillions of kilometers). So the earth is safe... For now....


Dark Matter

Super massive black holes may be the source of huge amounts of gravity, but they don't have enough power to hold a galaxy together, according to the laws of physic, a galaxy should fly apart. Why don't they?

Because there's something out even more powerful than a super massive black hole. It can't be seen, and virtually impossible to detect, but it's there. And it's called dark matter, and it's everywhere.

- Scientist are discovering that dark matter doesn't just hold em together, might have sparked them into life as well.

- They think dark matter was created into the Big Bang, and that dark matter became the seed of the Galaxy, even though they have no idea what it really is and no idea what it's made of.

- They think that dark matter weight for weight make up for x6 as much as all other matter in the Universe.

Recently it's been detected in deep space, it bends it, in a process called gravitational lensing. Allows us to detect the presence of dark matter. As a beam of light is travelling towards us, if it passes by dark matter, it gets deflected around it by the gravitational pull.

Triggers the birth of galaxies, and keeps them together, scientists call it, the master of the Universe.


Unfathomable vastness

Scientist have come so far, they've built almost the whole Universe in a super Computer. Here you can't see individual Galaxies, can't even see clusters. But what you can see is Super Clusters, linked together in filaments, in a vast cosmic web. One finds a cosmic web which lights up all of the Universe, making the Universe looks like a gigantic sponge.

Each of the filaments is home to millions of Galaxy clusters, all bound together by dark matter. In the simulation, the dark matter glows along the filaments.



It's a giant cosmic web, and hidden deep within one of these filaments are our Milky way.


Dark Energy

In recent times, the last decade scientists found something new, kinda scary. Dark Energy, far more mysterious than dark matter, since we don't have the slightest idea what it is or what it's doing. Like space has little springs in it, make things repel each other and pushes things apart.

If Dark Energy wins vs Dark matter, it make Galaxies spread apart and push things away from each other. But that's not going to happen for a very very long time (trillions of light years).


Fantastic time to live in

We're extremely fortunate, life has only evolved on earth because our tiny solar system was born in the right part of the Galaxy, any closer to the center, we wouldn't be here. Since life there is extremely lively, radioactive.

To far away from the center would be just as bad, ain't as many stars, we might not exist at all. We're not to far, not too close, perfect distance.

Endless questions to ask, and mysteries to solve. More and more scientists are focusing on Galaxies, it's amazing time to live in, where we're making the most extraordinary discoveries imaginable


PS,
The Milky Way is on a collision course with Andromeda, and since the bigger of galaxies crashing eats and consume the smaller, Milky Way will lose. Which is doomsday of our own Galaxy, but according to Astronomers it'll be amazingly beautiful.

PPS,
In 5 billion years