NASA astronaut Ed White during a spacewalk June 3, 1965. In his hand, the Gemini 4 astronaut carries a Hand Held Self Maneuvering Unit (HHSMU) to help him maneuver in microgravity. Credit: NASA
Space may be pretty, but it’s dangerous. Astronauts face a much higher dose of ionizing radiation than us Earth-bound folks, and a new report says that NASA’s current guidelines and risk assessment methods are in serious need of an update.
An illustration of the Cassini probe. Measurements of the mass of Saturn's rings taken by Cassini allow scientists to estimate the age of the rings. Image: NASA/JPL-Caltech
It’s tough to see inside of Saturn, because the atmosphere is opaque to all wavelengths of radiation. We have to rely on computer simulations and physics-based guesswork to try to understand the interior of that giant world. But researchers are becoming more adept at a different technique: looking for the slightest motions in the rings of Saturn.
If it were’t for an enormous halo of dark matter enveloping our galaxy, the spin-rate of our central bar should stay pretty constant. But researchers have recently inferred that it has slowed down by almost 25% since its formation, a clear sign of the presence of dark matter.
Artistic impression of a star going supernova, casting its chemically enriched contents into the universe. Credit: NASA/Swift/Skyworks Digital/Dana Berry
In 1181 CE, Chinese and Japanese astronomers noticed a “guest star” as bright as Saturn briefly appearing in their night sky. In the thousand years since, astronomers have not been able to pinpoint the origins of that event. New observations have revealed that the “guest star” was a supernova, and a strange one at that. It was a supernova that did not destroy the star, but left behind a zombie that is still shining.
This image of the supernova remnant SN 1987A was taken by the NASA/ESA Hubble Space Telescope in January 2017 using its Wide Field Camera 3 (WFC3). Since its launch in 1990 Hubble has observed the expanding dust cloud of SN 1987A several times has helped astronomers get a better understanding of these cosmic explosions. Supernova 1987A is located in the centre of the image amidst a backdrop of stars. The bright ring around the central region of the exploded star is material ejected by the star about 20 000 years before the actual explosion took place. The supernova is surrounded by gaseous clouds. The clouds’ red colour represents the glow of hydrogen gas. Image Credit: NASA, ESA, and R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation) and P. Challis (Harvard-Smithsonian Center for Astrophysics)
Using a new observatory, a team of Chinese astronomers have found over a dozen sources of ultra-high energy cosmic rays. And those sources aren’t from some distant, exotic corner of the cosmos. They come from our own backyard.
Visualization of the solar wind encountering Earth's magnetic "defenses" known as the magnetosphere. Clouds of southward-pointing plasma are able to peel back layers of the Sun-facing bubble and stack them into layers on the planet's nightside (center, right). The layers can be squeezed tightly enough to reconnect and deliver solar electrons (yellow sparkles) directly into the upper atmosphere to create the aurora. Credit: JPL
Scientists have found the unmistakable presence of certain isotopes in an iron meteorite. Since these meteorites are thought to leftover bits of planetary cores, similar isotopes must be in the Earth’s own core. And the only place to get those isotopes is from the solar wind.
In anticipation of the first image of a black hole, Jordy Davelaar and colleagues built a virtual reality simulation of one of these fascinating astrophysical objects. Their simulation shows a black hole surrounded by luminous matter. This matter disappears into the black hole in a vortex-like way, and the extreme conditions cause it to become a glowing plasma. The light emitted is then deflected and deformed by the powerful gravity of the black hole.
Astronomers recently caught a supermassive black hole gulp down a star. It flared in exactly the same way as its smaller cousins do when those black holes have a snack. It just took longer and was a million times brighter.
For the first time astronomers have observed waves of magnetic energy, known as Alfvén waves, in the photosphere of the sun. This discovery may help explain why the solar corona is so much hotter than the surface.
An illustration of a protoplanetary disk. The solar system formed from such a disk. Astronomers suggest this birthplace was protected by a larger filament of molecular gas and dust early in history. Credit: NASA/JPL-Caltech/T. Pyle (SSC)
Planets form from the accumulation of countless grains of dust swirling around young stars. New computer simulations have found that planets begin forming earlier than previously thought, when a planet’s star hasn’t even finished forming yet.
The NASA/ESA Hubble Space Telescope has captured this vivid image of spiral galaxy Messier 77 — a galaxy in the constellation of Cetus, some 45 million light-years away from us. The streaks of red and blue in the image highlight pockets of star formation along the pinwheeling arms, with dark dust lanes stretching across the galaxy’s starry centre. The galaxy belongs to a class of galaxies known as Seyfert galaxies, which have highly ionised gas surrounding an intensely active centre.
To trigger star formation, you need to compress a lot of gas into not a lot of volume. To make a lot of stars at once, you need to really pack it in. Until now, astronomers haven’t been sure how to pull this off. But a collection of 20 papers outlines how to do it: make giant clouds of gas crash into each other.
