A beautiful new image of Earth and Moon from the Chinese Chang’e 5 T1 spacecraft.
Comets have been in the news a lot recently, with the ongoing investigation of comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft and the close flyby of Mars by comet Siding Spring this past week. But there is also another comet discovery – one much further out from our solar system. With the help of the HARPS instrument, on the European Southern Observatory’s (ESO) 3.6-meter telescope, astronomers have identified nearly 500 comets orbiting the nearby star Beta Pictoris, as part of an unprecedented new survey of exocomets orbiting other stars.
Venus is one of the most inhospitable places in the Solar System, with temperatures hot enough to melt lead, crushing air pressure on the surface, and thick, toxic clouds perpetually hiding the planet itself from view. Now new research is helping to solve a long-standing mystery by showing that there may be frost on the surface. Not water frost, of course, given the conditions, but rather a bizarre frost composed of heavy metals.
It wasn’t that long ago that Earth was thought to be the only place in the Solar System capable of having liquid water oceans, but now we know of several moons that do as well, including Europa and Enceladus, and likely Titan and Ganymede as well. In all these cases, the oceans are below ground, similar to ocean water below ice sheets at the Earth’s poles. Now there is yet another moon which might be added to this special list: Saturn’s moon Mimas.
The Solar System is full of surprises. Mercury, the planet closest to the Sun, is a baking hot world, as would be expected. It is one of the last places where you would think anything would or could be frozen, but things aren’t always as they seem. There has been tantalizing evidence already for water ice deposits in craters at Mercury’s north pole, and now the MESSENGER spacecraft in orbit around the small planet has visually confirmed it for the first time.
Many different kinds of exoplanets have been found by astronomers, from giant “hot Jupiters” and “super Earths” to smaller rocky worlds like Earth or Mars. Now, another type has been discovered, an “ice giant” similar to Uranus or Neptune in our own Solar System. The planet is about 25,000 light-years away in the constellation Sagittarius and is one of the first found that appears to be similar to the ice giant planets in our Solar System, Uranus and Neptune, which are part gas and part ice in composition. The discovery was made by an international team of astronomers, led by Radek Poleski, a postdoctoral researcher at Ohio State University.
The Rosetta spacecraft has taken another “selfie” photo with the comet 67P/Churyumov-Gerasimenko in the background. Rosetta was only 16 kilometres (10 miles) from the comet at the time.There is even a jet clearly visible, emanating from the “neck” region of the double-lobed comet!
Being able to find exoplanets orbiting distant stars is a major accomplishment in itself, and fine-tuning the data enough to discover details about the characteristics of those planets is quite another. Not an easy task. Astronomers have had some initial success, but now they have been able to create the most detailed weather map for any exoplanet so far.
A new image from the Rosetta spacecraft, using the high-resolution OSIRIS camera, of a huge boulder on the surface of the comet. The boulder is about 45 metres (147 feet) across and named Cheops, after the largest pyramid at Giza in Egypt. In the wider view image below, it is the largest boulder near the centre of the photo.
A great image from the Lunar Reconnaissance Orbiter, showing the Earth, and, far in the distance, Mars, which looks like a very tiny speck where the label is near the top of the image. Click on image to zoom in. Mars is much farther away than the Moon! A significantly larger version of the photo is available here.