It hasn’t been found yet – let me make that clear. But with evidence that it should exist, astronomers are looking more closely at the proposed planet nine and how it might have formed, and how it could have ended up in such a distant orbit. When you start to think about how a planet ten times the mass of Earth could have ended up more than ten times as far from the Sun as Neptune, a few scenarios pop into mind: It was formed in the inner solar system, where interactions with gas giants or another star pulled it out It formed...
The closest star to the Earth, aside from the Sun, is Proxima Centauri, a small red dwarf star that is part of the Alpha Centauri system, roughly 4 light years away. If you don’t know light years, the distance is a staggering 37,800,000,000,000 Km. Beyond that our stellar neighbourhood fills in as you move 20 light years in any direction, and by 100 light years, there are dozens of stars around us. This gives a stellar density of about 0.14 stars per cubic parsec (a parsec is about 3.26 light years), pretty normal in terms of the number of stars in a given...
If a supernova were to go off somewhere in our galaxy, the minimum safe distance for Earthbound life would be about 50 light years. Any closer than that, and we would experience an intense blast of high energy radiation and an eventual shower of radioactive particles. It would be like nuclear bombs were set off all around the Earth, causing little destruction but a lot of radioactive fallout. Supernovae are incredibly powerful to be able to cause such damage at 50 light years, but even at larger distances, we can see evidence of their effects here on Earth. A team of...
Galaxy NGC 4569 is a spiral galaxy that is part of the Virgo cluster, around 55 Million light years distant. Like any other spiral galaxy, we can learn about its motion through the cluster, the properties of its stellar population, and how quickly its converting gas and dust to stars. But this galaxy has an interesting property, it’s missing a lot of gas. For years, astronomers have had ideas about where the gas has gone, and with new data from the Canada-France-Hawaii Telescope (CFHT), they now have the answer. The gas is being stripped off of the galaxy, and is now...
I’ve covered a few ‘hidden galaxy’ stories lately, from the ultra high resolution see-through of Andromeda, to dark dust in front of M81 and M82. Now, hundreds of new hidden galaxies have been revealed by a team of astronomers who are looking straight through the Milky Way for the first time ever, shedding light on the structure of new galaxy clusters and the enigmatic pull of the ‘great attractor.’ The Earth is not stationary in space. It orbits the Sun, which in turn orbits the Milky Way galaxy, which then moves through the Universe as part of a galaxy cluster. ...
In the early universe, there was a huge amount of swirling matter and light that didn’t really have much structure. Compared to today’s much more regular dotting of galaxy clusters and superclusters, the early universe was all over the place. But as will all things, there had to be a first. a first star, a first galaxy, and even a first galaxy cluster. The massive cluster of galaxies known as IDCS J1426.5+3508 is the most distant massive galaxy cluster ever discovered, and it has some interesting properties that point to how it formed and evolved so quickly. One such property is...
Predicting the death of a star is easy. If we know how massive it is, and what stage of life it’s in, we know that it should explode eventually, within a set timeframe of many hundreds of thousands, or even millions of years. But on human timescales, that is just not good enough. What if we could predict a supernova explosion within a few months? For something that lives for so long, this would be a triumph in our understanding of the universe. Over the past couple of years, this is exactly what happened. Here’s how. A supernova is one of the most...
Nebula. Collapse. Protostar. Main Sequence. Red Giant. Planetary Nebula. White Dwarf. This is the cycle of life for a star like our Sun. By observing stars across the galaxy, we see snapshots of different points in a star’s life cycle. It’s the same with people; If you went for a walk in a city and observed people for a day, you would see every single stage of a person’s life: Infant, child, adolescent, youth, adult, middle aged, senior. How would you put them in order if you knew nothing about them? With people you might go up and ask them, but with stars we can...
If you look up into the sky on a clear night, you would see thousands of stars. There are surely many more that you would need a telescope to see. But there are not stars everywhere. You can zoom in further and further with bigger and bigger telescopes, until eventually you find gaps where you simply don’t see stars. For a long time it was thought that the gaps were empty, until the Hubble telescope peered through the darkness by taking a 200 hour exposure of a supposedly empty patch of sky. What it revealed was a universe full of...
One of the greatest scientific discoveries of all time came with the invention of the spectroscope by Joseph Von Fraunhofer in 1814. It enabled us to look out at the universe and realize that the same basic building blocks that made you and I and all other life, were the same things that make up everything else in the cosmos. The tiny atoms in our bodies all started out at the center of a massive star billions of years ago. So naturally, when we talk about the odds of life forming elsewhere, we have to include a study of where...
