Category Astronomy/Space

The smallest planet in our Solar System will pass directly between the Earth and the Sun May 9. The last time this happened was in 2006, and the next 2 occasions will be in 2019 and 2032. During the transit, which takes place in the afternoon and early evening in the UK, Mercury will appear as a dark silhouetted disk against the bright surface of the Sun.

From the UK the transit begins at 1112 GMT (1212 BST), when the limb of Mercury appears to touch the limb of the Sun, and ends at 1842 GMT (1942 BST) when the limb of the silhouetted planet appears to leave the Sun. Observers in different locations will see the transit taking place at a slightly different time, as the planet will appear to take a slightly different path across the Sun.

The transit of Mercury of November 2006...

This artist’s concept shows the distant dwarf planet Makemake and its newly discovered moon. Makemake and its moon, nicknamed MK 2, are more than 50 times farther away than Earth is from the sun. Credit: NASA, ESA, and A. Parker (Southwest Research Institute)

Peering to the outskirts of our solar system, NASA’s Hubble Space Telescope has spotted a small, dark moon orbiting Makemake, the second brightest icy dwarf planet – after Pluto – in the Kuiper Belt. The moon, S/2015 (136472) 1 and nicknamed MK 2 – is > 1,300X fainter than Makemake. MK 2 was seen approximately 13,000 miles from the dwarf planet, and its diameter is ~100 miles across. Makemake is 870 miles wide. The dwarf planet, discovered in 2005, is named for a creation deity of the Rapa Nui people of Easter Island.

The Kuiper Belt ...

Sunlight glints off of Titan’s northern seas this near-infrared, color mosaic from NASA’s Cassini spacecraft. Credit: NASA/JPL/Univ. Arizona/Univ. Idaho

A new study finds that a large sea on Saturn’s moon Titan is composed mostly of pure liquid methane, independently confirming an earlier result. The seabed may be covered in a sludge of carbon- and nitrogen-rich material, and its shores may be surrounded by wetlands. Of the hundreds of moons in our solar system, Titan is the only one with a dense atmosphere and large liquid reservoirs on its surface, making it in some ways more like a terrestrial planet.

Both Earth and Titan have nitrogen-dominated atmospheres — over 95% nitrogen in Titan’s case...

This illustration shows a star surrounded by a protoplanetary disk. Material from the thick disk flows along the star’s magnetic field lines and is deposited onto the star’s surface. When material hits the star, it lights up brightly. The star’s irregular illumination allows astronomers to measure the gap between the disk and the star by using a technique called “photo-reverberation” or “light echoes.” First, astronomers look at how much time it takes for light from the star to arrive at Earth. Then, they compare that with the time it takes for light from the star to bounce off the inner edge of the disk and then arrive at Earth. That time difference is used to measure distance, as the speed of light is constant. Credit: NASA/JPL-Caltech

For the 1st time, astronomers used echoes of light t...