We know that galaxies like our Milky Way are far more massive than we can see. The dark matter in the Milky Way makes up 90% of it’s total mass. Another way of saying this is the Mass to Light ratio, comparing the total mass inferred by the rotation speed of the galaxy to the total mass of stars in the galaxy. This ratio, M/L, for the Milky Way, is about 10. But for a galaxy cluster, the M/L ratio is more like 100. Galaxy clusters are not just dense collections of stars and massive galaxies, they are also immense...
Twenty years of hunting exoplanets has given us nearly 2000 chunks of non-fusing rock and gas. It’s also given us the statistics to show that the galaxy is likely to be filled to the brim with other worlds, giving incredible potential for finding other Earths and maybe even other life. The latest discoveries involve the use of better technology, more intuitive methods, and more comprehensive searches. This means that we aren’t just discovering planets that are further from Earth, we are finding the ones that are nearby, but small enough to have been hidden, until now. The red dwarf star...
Now that New Horizons has passed by Pluto and it’s moons, it’s time we updated out images of the entire system. Taking images from New Horizons, today’s APOD shows the relative sizes of the moons with the best photos we have of them to date. Looking at the image, it makes sense that Nix and Hydra weren’t discovered until 2005, and that Kerberos and Styx were not found until 2012. The moons are so tiny and distant, and are dwarfed by the larger Charon and central Pluto. As far as we know, this is it for Pluto’s moons, since we haven’t...
Every so often we see a new set of images from Pluto, giving us a chance to rediscover it multiple times. It’s like we are experiencing the July fly-by over and over again, and each new set of images reveals something new and exciting. I feel the same sense of excitement and discovery each time I see a new image, realizing that it spent 6 hours as a beam of light crossing the 5 Billion Kilometres of the solar system to connect us to the New Horizons probe, a lonely little piece of human ingenuity flying through the darkness. Here...
For years there has been talk of a subsurface ocean present within Saturn’s icy moon Enceladus. Many have simply assumed it to be fact, but the reality is, something so complex on a world so far away is very difficult to prove conclusively. But now, using data from over a decade of observations by the Cassini spacecraft, mission scientists have shown conclusively that Enceladus must have a global ocean beneath a surface of ice. Previous data analysis suggested that there was a lens-shaped liquid ocean beneath the south polar region of the planet, giving a source for the observed plumes...
Today is the day, 25 years ago, that the Hubble space telescope launched from the Kennedy Space Centre aboard the Space Shuttle Discovery. The world had high hopes for Hubble, but we had no idea what great treasures were waiting for us in the depths of the cosmos. No piece of technology in human history has, arguably, had a bigger impact on our understanding of the Universe. For the 25th anniversary, International Astronomy day is coinciding to tomorrow’s anniversary of the deployment of Hubble, since it usually falls on a Saturday. Events across the world will include arts and crafts, Astronomy demonstrations,...
With all the amazing Science coming from Mars in the last decade, its seems easy to conclude that humans have a good understanding of our rusty neighbour. And then something new and unexpected happens. To someone who thought we knew all there was to know, this may be a disappointment. But to a scientist who has a passion for discovery, new and unexpected results are where the biggest breakthroughs happen! Massive plumes have been spotted high in the atmosphere of Mars, at an altitude of over 250 Km, where the thin Martian atmosphere is nearly indistinguishable from the emptiness of...
