NASA's Juno mission to Jupiter made the first definitive detection beyond our world of an internal magnetic field that changes over time, a phenomenon called secular variation. Juno determined the gas giant's secular variation is most likely driven by the planet's deep atmospheric winds.
Like most planets in our solar system, the Earth has its own magnetic field. Thanks to its largely molten iron core, our planet is in fact a bit like a bar magnet. It has a north and south magnetic pole, separate from the geographic poles, with a field connecting the two. This field protects our planet from radiation and is responsible for creating the northern and southern lights – spectacular events that are only visible near the magnetic poles.
In 1960, famed theoretical physicist Freeman Dyson made a radical proposal. In a paper titled “Search for Artificial Stellar Sources of Infrared Radiation” he suggested that advanced extra-terrestrial intelligences (ETIs) could be found by looking for signs of artificial structures so large, they encompassed entire star systems (aka. megastructures). Since then, many scientists have come up with their own ideas for possible megastructures.
The constellation of Orion (The Hunter) is one of the most recognisable collections of stars in the night sky. We have noted Orion’s prominent stars for tens of thousands of years at least, and likely far longer. Chinese astronomers called it 参宿 or Shēn, literally “three stars”, for its three bright dots (which form the Hunter’s belt). The ancient Egyptians regarded it as the gods Sah and Sopdet, manifestations of Osiris and Isis, respectively, whereas Greek astronomers saw a brave hunter — the eponymous Orion — with his sword above his head, ready to strike.
NASA's Spitzer Space Telescope has revealed that some of the universe's earliest galaxies were brighter than expected. The excess light is a byproduct of the galaxies releasing incredibly high amounts of ionizing radiation. The finding offers clues to the cause of the Epoch of Reionization, a major cosmic event that transformed the universe from being mostly opaque to the brilliant starscape seen today.
The first type of molecule that ever formed in the universe has been detected in space for the first time, after decades of searching. Scientists discovered its signature in our own galaxy using the world’s largest airborne observatory, NASA’s Stratospheric Observatory for Infrared Astronomy, or SOFIA, as the aircraft flew high above the Earth’s surface and pointed its sensitive instruments out into the cosmos.
If it weren’t for the sun constantly showering us with energy, there would be no life on Earth. But eventually stars like it run out of fuel, expand into red giants and finally collapse into small, faint objects called white dwarfs. So what will happen to us and the other planets in our solar system when the sun dies? It’s not been entirely clear.
New findings have emerged about five tiny moons nestled in and near Saturn's rings. The closest-ever flybys by NASA's Cassini spacecraft reveal that the surfaces of these unusual moons are covered with material from the planet's rings — and from icy particles blasting out of Saturn's larger moon Enceladus. The work paints a picture of the competing processes shaping these mini-moons.
This fuzzy orb of light is a giant elliptical galaxy filled with an incredible 200 billion stars. Unlike spiral galaxies, which have a well-defined structure and boast picturesque spiral arms, elliptical galaxies appear fairly smooth and featureless. This is likely why this galaxy, named Messier 49 (M49), was discovered by French astronomer Charles Messier in 1771. At a distance of 56 million light-years and measuring 157,000 light-years across, M49 was the first member of the Virgo Cluster of galaxies to be discovered, and it is more luminous than any other galaxy at its distance or nearer.