A couple of days ago, the still-active Cassini spacecraft orbiting around Saturn performed a flyby of the small Moon Hyperion, taking high resolution photos of the surface, and showing the sponge-like surface of the moon in a different light. Hyperion is a moderate 250 kilometers wide, yet it doesn’t tug very hard on Cassini. Performing measurements of its surface gravity, Cassini has shown that the moon is mostly empty space, similar to a pumice stone on Earth. The odd shapes of the craters are thought to be a result of this. When an impactor hits Hyperion, it blows the material...
When Canadian Astronaut Chris Hadfield was in space, on the International Space Station (ISS), he stayed there for six months, the standard length of stay for an astronaut. On the ISS, three of the six-person crew are replaced every three months. After returning to Earth, Hadfield could barely walk. He had lost bone density and muscle mass, his immune system weakened, cardiovascular functions slowed, and he produced less red blood cells. The lack of gravity is bad for humans, The longest a human being has ever been in space was Russian cosmonaut Valeri Polyakov, who was in space for a staggering...
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...
How do we measure the rotation speed of a planet? Exactly as you would expect. Watch the surface, look for markable features, and time how long it takes until those features pass the same point again in the future. But how can we possibly nail down this information when the planet has little to no visible surface features. Gas giant planets are great examples of this. Jupiter is a bit easier since it has plenty of storms and separated cloud layers along the planet’s rotation axis, but the other three are much tougher. Aside from hard-to-spot features, gas giants also...
Some of the moons of gas giant planets have a unique property: They are worlds that have a source of heat other than the Sun. The huge tidal forces imparted by their host planet and fellow moons cause their crust to grow and shrink, creating huge friction and heating the rock. It means that even if these moons are far from the warmth of the Sun, they can still host liquid water. There are two moons in our own solar system that are especially enticing: Jupiter’s second moon Europa, and the icy moon of Saturn known as Enceladus. Each host...
Even I was blown away when I saw this image a friend sent me. Gravitational lensing is a rare occurrence, and a supernova is a rare occurrence, so to see a supernova in a gravitationally lensed galaxy deep within the universe is exceptional. So exceptional that it was spotted for the first time ever in a Hubble image of the distant universe. That dot in the image is a single supernova in a very distant galaxy, split into four images by the gravitational lensing of the galaxy cluster in front of it. But there is also a secondary lensing effect from...
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...
Image submitted to an image processing competition called ‘Hubble’s Hidden Treasures’ are expected to be amazing, but this is the only one I’ve seen that will make you happier. This cosmic ‘smile’ is in the constellation Ursa Major, and is made up of the light from four galaxies, each with Billions of their own stars. This is the biggest happy face ever found! The two eyes are very distant galaxies known as SDSSCGB 8842.3 and SDSSCGB 8842.4. So why do we see this ring structure? You might think that the Galaxy is stretched by gravity, but its something much more...
Everything in the universe that has mass, has gravity. It’s easy to understand that the Earth, large as it is, has gravity, which pulls on us constantly, keeping us on terra firma. It’s just as easy to understand that other large objects have gravity, like the Moon, planets, and the Sun. However, it’s much harder to understand that every person on Earth has gravity. Strangely, you exert a force on the Earth, and on every other human. You also exert a force on every rock, tree, and creature that roams the Earth, and they all exert a force on you....
NASA is sure to start selling trips to these fabulous space destinations! The only problem is that we have no way of getting there, or more importantly, back home. Still the posters give a great homage to the ‘see America’ posters of the 1920s, and they sure make me want to visit. Kepler 186f is a habitable zone planet around a red dwarf star, meaning it could support liquid water. If any plant life forms on this planet, it would photosynthesize differently, potentially giving it a red colour palette. HD 403007g is a planet with 8 times the mass of Earth....
