All this long human story, most passionate and tragic in the living, was but an unimportant, a seemingly barren and negligible effort, lasting only for a few moments in the life of the galaxy. When it was over, the host of the planetary systems still lived on, with here and there a casualty, and here and there among the stars a new planetary birth, and here and there a fresh disaster. Olaf Stapledon, Star Maker
Looking back to the instant of creation is a relatively new idea. The Big Bang theory is widely accepted. But the concept is less than a century old. But all this changed in 1929. At California’s Mount Wilson Observatory Edwin Hubble studied the light from galaxies. He observed that the farther away the galaxy, the longer the wave-lengths of light it emits ... If a galaxy is moving away from us, its light-waves stretch, becoming longer and redder. It’s called red-shifting ... Nearly all galaxies are receding from us at a million miles an hour ... The universe is expanding outward from a single point ... Out of the fireball, the four fundamental forces of nature formed. These forces underpin everything around us. Gravity is the reason stars and planets formed ... Electromagnetism lights our cities, runs our phones and connects our computers. And the two nuclear forces, strong and weak, bind the particles that make up our bodies and power the furnace of our sun ... Without them the universe would be a featureless fog of radiation ... How was mass developed in the first second of the Big Bang? Big Bang
If the expansion of the space of the universe is uniform in all directions, an observer located in any one of the galaxies will see all other galaxies running away from him at velocities proportional to their distances from the observer. George Gamow
The supermassive black hole at the centre of our galaxy is small compared to the supermassive black holes that we know about. Professor Ramesh Narayan, Harvard University
Roughly, these [supermassive] black holes seem to be a thousand times less massive than the galaxy in which it lives. Professor Ramesh Narayan
Black holes consume entire galaxies, and eat away at them very slowly. Dr John Hutchison
The smaller ones have around four times the mass of our sun and are fifteen miles in diameter. Some are much larger containing the mass of thousands of suns. And then there are the really big ones. Supermassive black holes that exist at the centres of galaxies like our own. Stephen Hawking’s Universe: Into the Universe, Science 2010
[Vera] Rubin’s findings suggested that the destiny of galaxies is governed by a vast and inscrutable network. Every galaxy is enveloped in dark matter, invisibly locking all the stars in its embrace with the gravity it exerts. The black emptiness of space it seems isn’t so empty after all. 99% of the universe could well be made up of dark matter. A sprawling cosmic web. Stephen Hawking’s Universe: On the Dark Side
Dark matter determines that fate of the universe. ibid.
We’re not sure what came first. The Galaxy or the Black Hole. Professor Michelle Thaller
Galaxies are violent. They are born in a violent history; they will die a violent death. Professor Michio Kaku
Astronomers had an existential shock! In one year we went from the universe being the Milky Way galaxy to the universe of billions of galaxies. Michio Kaku
Galaxies are gorgeous. They represent in some sense the basic unit of the universe itself. They’re like gigantic pin-wheels twirling in space. It’s like fireworks created by Mother Nature. Michio Kaku
Our galaxy is approaching Andromeda at the rate of about a quarter of a million miles an hour. Michio Kaku
Our galaxy is part of a local group of galaxies perhaps thirty. And our galaxy and Andromeda are the two biggest galaxies in this local group. Professor Michio Kaku
So galaxies must have formed out of that early universe. Professor Michael Strauss
How did galaxies come to have the shape they do? Was a spiral galaxy always a spiral galaxy? The answer is almost certainly no. Professor Michael Strauss
The very first galaxies that formed in the universe were small galaxies. Dwarf galaxies. And as time went on these small building blocks combined to make bigger on bigger galaxies, as a result of mergers and accretion. Avi Loeb, Harvard University
There is more to the galactic centre than cosmic chaos. At its heart, hidden by a shroud of dust and blinding light, lurks the most bizarre entity in the universe. No-one knows exactly how it got there or the full extent of its gravitational power. Unfolding Universe, Discovery 2002
Einstein’s theory predicts a class of objects with such intense gravity that nothing, not even light, can escape their grasp. He called them dark stars. But he didn’t believe they really existed. As it turned out his theory was right. There is a kind of star that grows so heavy that it collapses under its own weight. The mass of many suns is sucked down to a tiny single point. ibid.
In our galaxy alone there may be millions. ibid.
The supermassive black hole is three million times the weight of the sun squeezed smaller than a speck of dust. But this tiny object is one of the most veracious predators in the universe: it eats stars. ibid.
The new hybrid galaxy, half Andromeda, half Milky Way, will be more of a ball than a disc. In its core two supermassive black holes will orbit each other in a tightening spiral until they finally merge. As our new galaxy falls towards the Virgo super-cluster more titanic collisions are in store. ibid.
Our sun is one of billions of stars in the Milky Way Galaxy. And our galaxy is one of hundreds of billions, maybe a trillion, in the known universe … the realm of alien galaxies. The Universe s1e9: Alien Galaxies, History 2007
Pictures from the Hubble Space telescope show the wide variety of alien galaxies. ibid.
Galaxies seem to naturally form these spiral density waves. ibid.
There is a region at the core of our galaxy the Milky Way where nothing escapes … a supermassive black hole. ibid.
Chaotic and breathtaking. Their beauty forms from the emptiness of space. Wisps of matter. At times coming together, at others flying apart. Filmy, veiled, billowing masses, some dark, some glowing in brilliant colours, many taking the shapes of things that are eerily familiar. Neither stars nor planets, they are the crown jewels of the galaxy. The Universe: Nebulas s2e14
It is one of the most famous space photographs ever taken. As seen by the Hubble Space Telescope it shows the Pillars of Creation – massive columns of dust and gas seven light years long. ibid.
Many also have names inspired by their locations or shapes. ibid.
The riddle of the nebulas is how they can form from almost nothing at all. ibid.
The questions surrounding the shapes of nebulas are among the most perplexing in all of astronomy. ibid.
There are at least two types of black holes: one is called a Stellar Mass Black Hole, which is approximately three to thirty times the mass of our sun. It’s speculated that one hundred million of these exist in our Milky Way Galaxy. And similar numbers exist in other galaxies. The other type is a Supermassive Black Hole, which is millions to billions of times the mass of our sun. The Universe s2e2: Cosmic Holes, History 2007
At least one hundred billion single galaxies exist in the observable universe. They range in size from ten thousand to millions of light years across. The Universe s2e16: Biggest Things in the Universe, History 2008
Throughout the universe galaxies crash into each other at phenomenal speed. This may be the fate of the Milky Way. The most violent impacts in the universe occur when galaxies collide ... Our own galaxy is at risk of crashing with its closest neighbour Andromeda. Cosmic Collisions: Galaxies, Discovery 2009
It’s a collection of gas, dust, planets and millions and millions of stars. ibid.
The galaxy can be a dangerous place when you’re on your own. Star Trek: Deep Space Nine s1e7: Q-Less, Q
Trust me, the galaxy is a pretty rough place. You people are much better off staying right here on Earth. Star Trek: Deep Space Nine s4e8: Little Green Men, Quark to Earthlings
Black holes are born from dying stars. And most are small. And thirty kilometres across. But now scientists have discovered some black holes are much bigger: they’re called supermassive black holes. They’re the same size as our entire solar system. And one of these monsters lies at the heart of our own galaxy. How the Universe Works s1e2: Black Holes, Science 2010
Everything in our galaxy including our own solar system orbits around a supermassive black hole. But the Milky Way is not the only galaxy with a black hole at its centre. There are supermassive black holes at the heart of most galaxies in the universe. The Andromeda Galaxy is our closest neighbour. It circles a supermassive black hole weighing one hundred and forty times more than our sun. ibid.
Quasars blast away huge quantities of gas from the surrounding galaxy. The equivalent of ten Earths every minute. Black holes suck gas in; quasars blow it out. But eventually there’s no gas left to make stars. And the galaxy stops growing. With no gas left to feed on, the quasar jets shrink and die. What’s left is a supermassive black hole at the centre of the galaxy with a lot of infant stars. Just like our Milky Way when it was young. ibid.