Why does the Sun seem red near the horizon? Why does the Moon do the same? We know the Moon isn’t actually changing colour, and the Sun isn’t either. So what is happening to the light? The first thing to note about the image above is that the size of the Moon doesn’t change, showing that the well-known ‘Moon Illusion,’ where the Moon appears larger near the horizon, is just that – an illusion. The second is of course the gradual change in hue as the Moon rises. The reason for the colour shift really has nothing to do with the Moon...
Every year, as the Earth revolves around the Sun, we pass an imaginary line directly from the Sun to Saturn. The Sun is on one side of us and Saturn is on the other. When two bodies are on opposite sides of the Earth like this we call it opposition. Saturn’s opposition for the year was on May 23rd, and even though it has been a few days, you can still see Saturn up pretty much all night. Along with opposition, we can clearly see the rings, but Saturn does wobble on a 29.5 year cycle, meaning there are times...
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...
At least once a month we hear of a new exoplanet with a strange and amazing story. From the ‘Super-Saturn’ ringed world to Magnetic Fields to systems of three Earths, there is an abundance of planets and strange systems. The latest weird discovery brings us to a star 1,500 light years away in the constellation Cygnus. The small-Mercury sized planet it hosts orbits in only 16 hours, bringing its surface temperature to over 1,800 degrees celsius. This amount of heat is enough to vapourize rock, and so the star is literally roasting the planet and blasting away its surface. The dust...
