“We don’t understand how a single star forms, yet we want to understand how 10 billion stars form.” -Carlos Frenk
The Universe has been around for a long time: nearly 14 billion years, to the best of our knowledge. When it was very young, there were absolutely zero stars in it, while today, there are hundreds of billions of galaxies, each of which contains anywhere from a few billion to many trillions of stars.
Image credit: NASA, ESA, and the Hubble Heritage (STScI / AURA) - ESA / Hubble Collaboration
The galaxy shown above, NGC 2841, is very similar to our own Milky Way. Approximately the same size and shape, this massive spiral is full of dust lanes, flocculent arms (with multiple branches), a central bulge, and perhaps the only major apparent difference is there’s no central bar like the Milky Way has. But one other important thing this galaxy has in common with our own is a very low rate of star formation.
How can you tell how quickly a galaxy is forming stars? Compare the spiral above with the Whirlpool Galaxy, below.
Image credit: NASA, ESA, S. Beckwith (STScI), and The Hubble Heritage Team (STScI/AURA).
The beautiful grand-design ...