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Category: space – Page 1,017

Jupiter’s Moons Leave Signature Spots in Its Aurorae

Despite being wildly different from Earth in almost every way, Jupiter does feature some familiar phenomena—including aurorae, what we call the Northern and Southern lights. But Jupiter’s aurorae have something Earth’s don’t: strange features caused by the Jovian moons.

Scientists analyzing data from the Juno spacecraft spotted some of these anomalies in action. They saw swirls and spots caused by Jupiter’s moons Io and Ganymede. And, as is often the case, things weren’t what they seemed from far away.

Milky Way still bears the 10-billion-year-old scars of a galactic collision

Galaxies collide with each other on a pretty regular basis. Our own Milky Way, for instance, has gobbled up dozens of smaller galaxies in the past, and Andromeda is currently hurtling towards us at 109 km (68 mi) per second. An international team of astronomers has now found evidence of a celestial smash-up between the Milky Way and an unknown dwarf galaxy that took place around eight to 10 billion years ago, and forever changed the face of our home galaxy.

According to the researchers, the evidence for this cosmic collision is all around us, from the bulge at the center of the Milky Way to the spread-out halo at the very fringes. The now-defunct dwarf galaxy has been dubbed the “Gaia Sausage,” after the ESA’s Gaia satellite used to plot out the trajectories of its stars, and the apparent shape those measurements revealed.

“We plotted the velocities of the stars, and the sausage shape just jumped out at us,” says Wyn Evans, co-author of the study. “As the smaller galaxy broke up, its stars were thrown out on very radial orbits. These Sausage stars are what’s left of the last major merger of the Milky Way.”

Did Something Massive Smash Into Uranus?

Uranus really is strange. Not only does it rotate on an axis that sits at a 98-degree angle to its orbital plane, but, unlike the other giant planets, it doesn’t appear to release more heat than it receives from the Sun. Its magnetic field, too, appears warped compared to the Earth’s. An impact could perhaps help explain some of these strange traits.

Scientists have been simulating giant impacts into Uranus since the early 1990s, according to the new paper published in the Astrophysical Journal. This time around, researchers built a new simulation with the newest and best available data of the planet’s composition. This allowed them to model how a giant impactor, perhaps one to three times the mass of Earth, would have deposited “material and energy inside Uranus” and how much debris would be left over, from which moons could form.

“This study provides some great new insights into what might have happened all those billions of years ago, with material left over from the impact possibly even serving to trap some of that heat inside,” Leigh Fletcher, Royal Society Research Fellow at the University of Leicester, told Gizmodo.

Birth of a planet captured for first time as gas giant bigger than Jupiter swirls into existence

E ven by astronomical standards it is a discovery that is out of this world.

Scientists have for the first time witnessed the birth of a planet, a huge gas giant many times the size of Jupiter, swirling into existence 370 light years from Earth.

The theory of how gas planets form from a vortex of hydrogen and helium molecules captivated by their own gravity, is now widely accepted by scientists. But it has never been seen before, until now.

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