One of the largest and brightest star clusters in the Milky Way galaxy is the Arches cluster, and its easy to see why. Lying only 100 light years away from the supermassive black hole that lies in the heart of our galaxy, it formed in an incredibly dense environment. It lies 25,000 light years from Earth in the constellation Sagittarius, and contains thousands of massive stars, including 160 that are hot, young, and exceptionally more massive than the Sun. Only 1 in 10 Million stars in the galaxy are as bright as these massive central 160 stars. Though it is...
It has been well established that Galaxies have formed during the last 13.7 Billion years of cosmic evolution. They didn’t just pop into existence, but developed in a long and arduous process that spans immense time. Many of them will continue to flourish for many Billions of years. If Galaxies do indeed have a birth, as has been seen, it stands to reason that they should someday ‘die’ as well. But have we ever seen the death of a galaxy? Have we ever seen the end for a massive collective structure of stars? We have seen galaxies collide and merge...
The Andromeda Galaxy is the closest large spiral to our own Milky Way, and the only major Galaxy moving toward us. Turns out its on a direct collision course, but we still have 3.5 Billion years to prepare, so its not exactly pressing news. On the plus side, studying Andromeda allows us to infer properties of more distant galaxies, and it gives us a map of what our own Milky Way Galaxy may look like. Astronomers using the Hubble Space Telescope have discovered a giant halo of gas around Andromeda, and the Milky Way may have a similar one. By...
When the first stars and galaxies started to form, it was like a spark of a massive chain reaction where the vast amounts of gas and dust that had clumped together were quickly converted into dense, luminous star clusters. This was the beginning of the formation of the heavier elements that would eventually make up all that we see on the planet Earth. But when did this massive tirade of star formation end? When we look at galaxies in the present epoch, most don’t form stars very rapidly at all, and giant elliptical galaxies are all but devoid of gas,...
Globular Clusters are tightly packed collections of hundreds of thousands of very old stars, spherically distributed around the Milky Way Galaxy. They undergo little change, have nearly no gas, and have a stellar density way higher than the rest of the Galaxy. The first one discovered, in 1665, is messier 22, one of the most well studied, easily visible, and interesting globular clusters. Based on observations, this globular cluster contains at least two black holes. It is also one of only three globular clusters ever found to host a planetary nebula, a gaseous shell emitted by a dying star with...
On the York Universe radio show this past Monday evening on astronomy.fm, I was having a discussion with another host about how so many things in Astronomy can take Millions or even Billions of years, yet there are still all kinds of phenomena that happen in seconds, hours, weeks, years, or on the scale of human lifetimes. Stars live for hundreds of Millions of years at the low end, yet the intense brightening from the Supernova death of a massive star lasts for only a few days or weeks. It’s as if the Universe is piquing our interest with short...
We call it dark matter because it doesn’t give off light, right? Well there is a lot of matter than doesn’t radiate, but the difference is that whatever the stuff is that we call dark matter doesn’t interact with anything through the small-scale fundamental forces. The only way we have been able to detect it’s presence is through large-scale gravitational interaction. Dark matter is ‘dark’ because it doesn’t interact with anything in a way that lets us figure out what it’s made of. Well now that we’ve got that out of the way, we can look at the new...
After reaching a deeper understanding of the subsurface ocean of Enceladus just yesterday, a stunning discovery has just been made about the largest Moon in the solar system. The largest moon of Jupiter, Ganymede, contains a subsurface ocean of it’s own. The discovery was made with the Hubble space telescope and a careful study of aurora on the giant moon. That’s right Ganymede has auroral activity. This is because it is the only moon in the solar system with a magnetic field. The magnetic field funnels radiation from the Sun toward the north and south poles, where it ionizes molecules...
The thing about black holes is that they are very dense. If we took the entire 2,000,000,000,000,000,000,000,000,000,000 Kg of the Sun (This is the real mass of the Sun) and turned it into a black hole, it would be about 6 Km in diameter. It is theorized that there are around 100 Million Black holes in the Milky Way Galaxy alone. But if they aren’t near a large reservoir of gas and dust, with their small size they are pretty harmless and invisible. The only way we could find them would be through their gravitational influence, which is hard to...
At one point in history, let’s say around 1994, astronomers were fairly confident in their understanding of the formation of planetary systems. Even though at the time we hadn’t found any planets orbiting other stars, they had long been theorized, and we figured that systems would form much like our own solar system. Rocky planets in the interior, gaseous giants further out, and a huge icy debris field at the outer edges. And then along came 51 Pegasi b. Half the mass of Jupiter, it orbits its star in only 4 days, far closer than Mercury. It was considered a...
