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...
Have you ever seen a picture of a comet or asteroid in the sky against a background of stars? Here let me show you. Can you spot the asteroid? Okay I confess there is no asteroid in the image above, but if there was you’d believe me because an asteroid in this image would be indistinguishable from the stars. They are all points of light, so how can you tell them apart? There’s something that separates asteroids, comets, planets, and all other solar system objects from background stars in an image. When you’re driving in a car and you look to the...
At this stage of our understanding of the planet Mars, we have seen salty water flowing (recurring slope lineae), found evidence of ancient riverbeds, and seen seasonal changes in the polar caps. But an important question is how does water behave on Mars? A bit of science here on Earth gives some insight. Water at sea level on Earth boils at 100 degrees Celsius, which actually defined the Celsius scale. But as pressure changes, liquids boil at different temperatures. As the atmosphere gets thinner, the boiling temperature of water decreases. On Mars, with it’s extremely thin atmosphere, this means that water...
If you haven’t already heard, Mercury is going to transit the Sun this coming Monday! It’s like a solar eclipse, except Mercury is covering the Sun instead of the Moon. And since Mercury is tiny and far away, it’s not so much ‘covering’ the Sun as it is passing across the face of the Sun in a barely perceptible way. The transit takes approximately 7 hours start to finish, and will occur on Monday, May 9th, 2016 from 7:12am to 2:42 pm EDT. If you miss this one, you can catch the next one in 2019. They happen a dozen times a...
As the search for planets in the galaxy continues, there are two places to focus on: Distant stars with potential large planets, and nearby stars with potential small planets. If we are able to find Earth-like planets orbiting nearby stars, they will be prime targets for future generations to explore. Astronomers have just announced the discovery of three new planets orbiting a star only 40 light years from Earth. The star is a very small red dwarf, only slightly larger than Jupiter, and even though it’s close to Earth, it can’t be seen with the naked eye or even with a large...
What is the difference between a comet and an asteroid? The typical response is that an asteroid is rocky and a comet is icy/gassy. Further than this, asteroids typically orbit closer to the Sun than Neptune, and comets orbit beyond this loose dividing line. But as with everything in nature, there are often exceptions to the rule. C/2014 S3 PANSTAARS is classified as a weakly active comet, originating in the Oort cloud with an orbital period of 860 years. As it approached the Sun, astronomers noticed that it was lacking the characteristic comet tail, resulting from the blast of solar radiation upon approach to the...
Life in the universe is a fascinating topic. The simplest question: Are we alone? It breeds so many deeper and more profound scientific questions, like “How many habitable planets are there?” “How likely is life to develop on any given planet?” and “How long can a civilization survive?” We can’t answer them definitively, but we can narrow it down. The Drake equation, shown above, was first developed by Frank Drake, the head of the Search for Extraterrestrial Intelligence (SETI), in 1961. He took the question of are we alone and made it quantifiable, in a probabilistic way. It lets us...
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...
I’ve written many times about the power of looking at different wavelengths of light to study different properties of the universe. From a visualization standpoint, there are other techniques that give you additional power when imaging. More than just the wavelength of light you’re using to show the detail, you can choose the range of wavelengths to bring forward certain features while suppressing others. The aptly-named spaghetti nebula, shown above, is a great example of this. A supernova remnant that covers the constellations Taurus and Auriga, the nebula is very large in the sky, covering three full moons worth (love that unit...
When could the Moon possibly be brighter than the Sun? The Sun is much bigger, produces energy, and gives all the energy needed for life on Earth. But if you look at the sky in gamma rays, the highest energy photons on the electromagnetic spectrum, you’ll see the Moon more easily than the Sun. Why? The Moon is the brightest gamma ray source in the sky, because it has no atmosphere or magnetic field. Essentially it has no protection from the dangerous cosmic rays that are constantly zipping through space. When they hit the Earth’s atmosphere they create a cosmic...
