Pluto's heart-shaped scar may offer clues to the frozen world's history
published 3 hours ago
When NASA’s New Horizons mission flew past Pluto in 2015, it gave humanity our first glimpse of a colossal depression on the isolated world. It's named Sputnik Planitia. Comparable in size to the country of Mexico and dominating one of Pluto’s hemispheres, Sputnik Planitia is likely the result of an impact — but few impact craters come in Sputnik Planitia's unique pear-like shape.
How Sputnik Planitia formed remains unknown, but researchers have now painted a possible picture of its origins. It's possible, they say, that a body about the size of Switzerland crashed into Pluto long ago, at a shallow angle. If true, this picture would also hint at what Pluto's interior may look like under its cryogenic surface.
"Most thought Sputnik Planitia was of impact origin, but nobody had been able to explain its distinctive pear shape," Harry Ballantyne, an astronomer at the University of Bern in Switzerland, told Space.com.
Sputnik Planitia's shape and colossal size — roughly 2,000 kilometers long (1,243 miles long) and 1,600 kilometers wide (994 miles wide) — are not the only reasons planetary scientists have looked at it with curiosity. Whatever created this formation managed to carve out a dent as deep as s 4 kilometers (2.5 miles); and at the bottom of the chasm appears to be a frozen expanse of nitrogen ice. Gravity ought to have slowly rotated Pluto such that the dent and its missing mass ended up at one of Pluto's poles — but, oddly enough, Sputnik Planitia remains around the equator.
One popular theory suggested that Sputnik Planitia was actually a hint of a global ocean buried under Pluto's surface. After a massive impact, liquid water from the ocean might have risen to fill the gap, which would have then been iced over with a nitrogen coating — explaining why Sputnik Planitia stayed on the equator. Still, some scientists remained unconvinced.
Scientists unravel mysteries of gamma-ray bursts — the universe's most powerful explosions
published 15 minutes ago
Scientists may be a step closer to discovering how gamma-ray bursts come to be some of the most powerful explosions in the known universe.
For context, a single gamma-ray burst, or GRB, can produce more energy in seconds than the sun will radiate in billions of years. Because of this power, scientists theorize that GRBs are created by some of the universe's most violent events. This includes things like supernova explosions that mark the deaths of massive stars and the collision and merger of two neutron stars, which are "dead" stars composed of the densest matter we know of, as well as outbursts from baby black holes.
Yet, aspects of these blasts remain shrouded in mystery, including the exact mechanism that launches a GRB and what exactly causes a "long" GRB that lasts more than 2 seconds versus a "short" GRB that lasts for less time.
One team of scientists from the University of Alabama in Huntsville, for instance, has been studying the light omissions of GRBs and how they change over time to better model these eruptions and finally crack their secrets.
"Despite being studied for over fifty years, the mechanisms by which GRBs produce light are still unknown, a great mystery of modern astrophysics," team leader Jon Hakkila, a scientist at the University of Alabama in Huntsville, said in a statement. "Understanding GRBs helps us understand some of the most rapid and powerful light-producing mechanisms that Nature employs.
While most of the US was sound asleep on Friday morning, China conducted an important launch from its Wenchang Satellite Launch Center. The Chang’e-6 lunar lander was hoisted into space by a towering Long March-5 rocket en route to the far side of the Moon. If everything goes as planned, this mission will be the first to return a sample from this barely explored region of Earth's satellite.
The far side of the Moon is sometimes called the "dark side," but that's because we know so little about it, not because it's dark. The Moon is tidally locked to Earth, so we always see the same side when we look up, with its familiar craters and expanses of cooled lava like Oceanus Procellarum. Returning a sample of dust and rock from the far side could help scientists unravel some vexing mysteries about how the Moon formed and what humans can expect when proposed long-term research outposts are constructed. In particular, China hopes its lunar landers will pave the way for its International Lunar Research Station (ILRS), reports Reuters.
The China National Space Administration (CNSA) expects Chang’e-6 to touch down on the far side of the Moon's Aitken Basin in early June. This region is near the south pole, which is of interest to scientists as it has large deposits of water ice inside permanently shadowed craters. Samples from this region could also help us understand how early impact events shaped the Moon and why the far side looks so different compared to the Earth-facing side.
