Galaxy Evolution Quotes

As soon as the idea of the Big Bang was proposed in the 1920s, astronomers set about trying to work out when the bang happened. Initial estimates were, not surprisingly, wildly inaccurate, but by the 1980s it was known that the universe was 15 billion years old, give or take 5 billion years.

My favorite galaxy of all is called the Sombrero, NGC 4594. It's an amazing galaxy that is really two galaxies in one.

You could think of the galaxy as a sort of stove with lots of pots on it, and the pots are the interstellar medium, like a chicken broth getting stronger with every reduction. Every time a supernova goes off and sends its heavy elements out into the interstellar medium, we cook up a stew that's better and better for solar systems and life.

Earlier generations of stars in the galaxy could well have had planets. But really, there was only hydrogen and helium to work with, so they'd all be gas giants and not small, rocky planets.

Evidence has been mounting for the key role that black holes play in the process of galaxy formation. But it now appears that they are likely the prima donnas of this space opera.

It's quite likely that planets and solar systems like ours could be forming in other galaxies in great numbers.

If you take a galaxy and try to make it bigger, it becomes a cluster of galaxies, not a galaxy. If you try to make it smaller than that, it seems to blow itself apart.

Finding the first seed black holes could help reveal how the relation between black holes and their host galaxies evolved over time.

The large-scale homogeneity of the universe makes it very difficult to believe that the structure of the universe is determined by anything so peripheral as some complicated molecular structure on a minor planet orbiting a very average star in the outer suburbs of a fairly typical galaxy.

There are lots of ideas which extend the Copernican principle one step further. We went from the solar system to the galaxy to zillions of galaxies and now to realising even that isn't all there is.

Data suggest that central black holes might play an important role in adjusting how many stars form in the galaxies they inhabit. For one thing, the energy produced when matter falls into the black hole may heat up the surrounding gas at the center of the galaxy, thus preventing cooling and halting star formation.

The early universe was a dusty place, and the UV radiation from the hot, young black holes and stars would get enshrouded by dust, re-radiated, and scattered into red wavelengths like infra-red, causing these objects to remain obscured.

We knew from theoretical models that mergers of massive, gas-rich galaxies were more frequent in the past. Now we've found that these mergers are responsible for producing both the nearby obscured quasar population and their distant cousins.