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...
It’s difficult to determine the history of the Solar System. The planets have been in their current orbits for Billions of years, and any signs of prior activity or configuration has to come from leftover geologies of smaller, rocky worlds. It makes it especially difficult when the Billions of interloper asteroids and comets throughout history have to be accounted for, adding to the already complex task. But if there is one thing humanity has going for us it’s the ability to theorize, model, simulate, and test scenarios here on Earth. We can try new ideas and see if they match...
We have found evidence of ancient impacts all across the Earth, from the famous Chixulub crater in Mexico to the Sudbury Basin a little bit closer to my home. From Space the remains look nothing like craters, millions of years of sediment and growth hide the massive regions from obvious detection, but signs remain of these massive events, even after millions of years. This week, what is possibly the largest impact crater basin ever discovered has been found in central Australia. And it is thought to originate from the breakup of a massive 400 Km asteroid into two pieces that...
Yesterday I posted some of my own photos of the Moon and Mars in conjunction from the night before. Last night I went out again knowing that there was another planetary conjunction in the works. The Moon was now with Venus. People on the internet and in person were asking me “Mars? I thought the Moon was near Venus,” and “Venus? I thought the Moon was near Mars.” It really speaks to the fact that most people don’t realize how quickly the sky changes from the point of view of an Earthbound observer. So what happened between the Mars-Moon and...
Every 29.5 days we see a new Moon, or rather we don’t see it, since it’s lost in the glare of the Sun. But a few days after the new moon, we can see it slowly move away from the Sun and become visible after sunset, with the thinnest crescent growing a bit larger each night. You may have heard that Mars and Venus also live in the Western sky after sunset, with Venus moving higher and Mars appearing to double back toward the Sun, soon to be lost in the glare of our home star. Last night I was...
The biggest problem in theoretical physics today is the marriage between Quantum Mechanics and Gravity. Throw in the fact that whatever theory comes out of it has to additionally be able to explain Dark Matter and Dark Energy, and we have ourselves a massive problem to solve. How do we reconcile the seemingly random probabilistic nature of quantum mechanics with the smooth, pliable space-time of General Relativity. We have two incredible theories that explain the Universe, make predictions accurately, and have led to amazing advances in technology and understanding, yet they completely disagree with each other at common scales. So...
As the Rosetta spacecraft remains in orbit around the comet 67P/Churyumov-Gerasimenko, the comet is slowly drifting toward its closest approach to the Sun, known as perihelion. As the comet moves closer to the Sun, intense sunlight liberates gases and dust in streams of material that form clearly visible streaks. The orbiter is able to sample some of the material liberated from the comet, and for the first time it has seen the tell-tale signature of Molecular Nitrogen. Nitrogen is abundant on Earth as a gas, constituting the majority of our atmosphere. It is also present in the atmospheres of Pluto and Neptune’s...
With all the talk of the large geomagnetic storm of the past few days, it’s important to understand that other worlds have beautiful auroral activity as well. Being on Earth and seeing the gorgeous displays that result from our magnetic field protecting us from harmful solar radiation, the best views come from Earth. But there are several other places in our own solar system that have aurora. Jupiter has a massive magnetic field, and its gigantic aurora are visible here. Jupiter’s moon Ganymede is the only moon in the solar system that has auroral activity. Saturn has its own, discovered...
Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights) are the most beautiful result of the Earth protecting us from a horrible death by solar radiation. Every time I see it, I marvel in the beauty and remind myself that I am still safe from being cooked by that giant ball of gas that is responsible for fundamentally fuelling all life on Earth. So when we have a lot of auroral activity, I pop over to spaceweather to see if it will be visible from where I live. Though it usually isn’t, today’s aurora are potentially visible, so I might...
Over the course of a day the Earth changes quite a lot. Lightning strikes the Earth 8 Million times per day as the mighty water cycle on our planet churns under the power of the Sun’s warmth and the Coriolis force on the Earth. But have we ever just stared at the Earth’s surface over the course of the day? Definitely. We have seen the day to day changes from many different altitudes above the Earth’s surface, and the above image shows stunning changes over the course of a day. But how do we get a picture like this?...
