HOTTEST
The shrinking mass of Pluto — Science News, August 28, 1971
Pluto was the last of the planets to be discovered (in 1930). If astronomers continue to make it lighter, it may be the first to disappear.… [The latest measurement] brings Pluto down to 0.11 of Earth’s mass, less than an eighth of its former self.… The wide discrepancies among the figures presented for the mass of Pluto illustrate the particular difficulties of measuring its mass.… If a planet has satellites, its mass can be determined from studying their motions.… But Pluto has no known satellites.
Update
The discovery of Pluto’s moon Charon in 1978 (SN: 7/15/78, p. 36) finally allowed astronomers to accurately calculate the planet’s mass: about 0.2 percent of Earth’s mass. Decades after scientists resolved Pluto’s heft, the planet received arguably the greatest demotion of all — a downgrade to dwarf planet (SN: 9/2/06, p. 149). Some astronomers have since proposed alternate definitions for the term “planet” that, if widely adopted, would restore Pluto to its former rank. More
The James Webb Space Telescope has spotted the earliest known galaxy to abruptly stop forming stars.
The galaxy, called GS-9209, quenched its star formation more than 12.5 billion years ago, researchers report January 26 at arXiv.org. That’s only a little more than a billion years after the Big Bang. Its existence reveals new details about how galaxies live and die across cosmic time.
“It’s a remarkable discovery,” says astronomer Mauro Giavalisco of the University of Massachusetts Amherst, who was not involved in the new study. “We really want to know when the conditions are ripe to make quenching a widespread phenomenon in the universe.” This study shows that at least some galaxies quenched when the universe was young.
Science News headlines, in your inbox
Headlines and summaries of the latest Science News articles, delivered to your email inbox every Thursday.
Thank you for signing up!
There was a problem signing you up.
GS-9209 was first noticed in the early 2000s. In the last few years, observations with ground-based telescopes identified it as a possible quenched galaxy, based on the wavelengths of light it emits. But Earth’s atmosphere absorbs the infrared wavelengths that could confirm the galaxy’s distance and that its star-forming days were behind it, so it was impossible to know for sure.
So astrophysicist Adam Carnall and colleagues turned to the James Webb Space Telescope, or JWST. The observatory is very sensitive to infrared light, and it’s above the blockade of Earth’s atmosphere (SN: 1/24/22). “This is why JWST exists,” says Carnall, of the University of Edinburgh. JWST also has much greater sensitivity than earlier telescopes, letting it see fainter, more distant galaxies. While the largest telescopes on the ground could maybe see GS-9209 in detail after a month of observing, “JWST can pick this stuff up in a few hours.”
Using JWST observations, Carnall and colleagues found that GS-9209 formed most of its stars during a 200-million-year period, starting about 600 million years after the Big Bang. In that cosmically brief moment, it built about 40 billion solar masses’ worth of stars, about the same as the Milky Way has.
That quick construction suggests that GS-9209 formed from a massive cloud of gas and dust collapsing and igniting stars all at once, Carnall says. “It’s pretty clear that the vast majority of the stars that are currently there formed in this big burst.”
Astronomers used to think this mode of galaxy formation, called monolithic collapse, was the way that most galaxies formed. But the idea has fallen out of favor, replaced by the notion that large galaxies form from the slow merging of many smaller ones (SN: 5/17/21).
“Now it looks like, at least for this object, monolithic collapse is what happened,” Carnall says. “This is probably the clearest proof yet that that kind of galaxy evolution happens.”
Subscribe to Science News
Get great science journalism, from the most trusted source, delivered to your doorstep.
As to what caused the galaxy’s star-forming frenzy to suddenly stop, the culprit appears to be an actively feeding black hole. The JWST observations detected extra emission of infrared light associated with a rapidly swirling mass of energized hydrogen, which is a sign of an accreting black hole. The black hole appears to be up to a billion times the mass of the sun.
To reach that mass in less than a billion years after the birth of the universe, the black hole must have been feeding even faster earlier on in its life, Carnall says (SN: 3/16/18). As it gorged, it would have collected a glowing disk of white-hot gas and dust around it.
“If you have all that radiation spewing out of the black hole, any gas that’s nearby is going to be heated up to an incredible extent, which stops it from falling into stars,” Carnall says.
More observations with future telescopes, like the planned Extremely Large Telescope in Chile, could help figure out more details about how the galaxy was snuffed out. More
THE WOODLANDS, TEXAS — Martian dirt may have all the necessary nutrients for growing rice, one of humankind’s most important foods, planetary scientist Abhilash Ramachandran reported March 13 at the Lunar and Planetary Science Conference. However, the plant may need a bit of help to survive amid perchlorate, a chemical that can be toxic to plants and has been detected on Mars’ surface (SN: 11/18/20).
“We want to send humans to Mars … but we cannot take everything there. It’s going to be expensive,” says Ramachandran, of the University of Arkansas in Fayetteville. Growing rice there would be ideal, because it’s easy to prepare, he says. “You just peel off the husk and start boiling.”
Science News headlines, in your inbox
Headlines and summaries of the latest Science News articles, delivered to your email inbox every Thursday.
Thank you for signing up!
There was a problem signing you up.
Ramachandran and his colleagues grew rice plants in a Martian soil simulant made of Mojave Desert basalt. They also grew rice in pure potting mix as well as several mixtures of the potting mix and soil simulant. All pots were watered once or twice a day.
Rice plants did grow in the synthetic Mars dirt, the team found. However, the plants developed slighter shoots and wispier roots than the plants that sprouted from the potting mix and hybrid soils. Even replacing just 25 percent of the simulant with potting mix helped heaps, they found.
The researchers also tried growing rice in soil with added perchlorate. They sourced one wild rice variety and two cultivars with a genetic mutation — modified for resilience against environmental stressors like drought — and grew them in Mars-like dirt with and without perchlorate (SN: 9/24/21).
No rice plants grew amid a concentration of 3 grams of perchlorate per kilogram of soil. But when the concentration was just 1 gram per kilogram, one of the mutant lines grew both a shoot and a root, while the wild variety managed to grow a root.
The findings suggest that by tinkering with the successful mutant’s modified gene, SnRK1a, humans might eventually be able to develop a rice cultivar suitable for Mars. More
Cocoons of debris around dying stars could shake ripples in spacetime unlike any astronomers have ever seen.
“This is a potential source of gravitational waves that has never been investigated before,” astrophysicist Ore Gottlieb of Northwestern University in Evanston, Ill., said June 5 in a news conference at the American Astronomical Society meeting in Albuquerque.
The waves could potentially be picked up in the latest run of LIGO, which began on May 24.
Since LIGO’s first detection in 2015, all the gravitational waves seen thus far have been from the spiraling death dance of two compact objects — black holes, neutron stars or both (SN: 2/11/16). These events give off what are called coherent gravitational waves. “You can think of it as an orchestra playing harmonically,” Gottlieb said.
.email-conversion {
border: 1px solid #ffcccb;
color: white;
margin-top: 50px;
background-image: url(“/wp-content/themes/sciencenews/client/src/images/cta-module@2x.jpg”);
padding: 20px;
clear: both;
}.zephr-registration-form{max-width:440px;margin:20px auto;padding:20px;background-color:#fff;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form *{box-sizing:border-box}.zephr-registration-form-text > *{color:var(–zephr-color-text-main)}.zephr-registration-form-relative-container{position:relative}.zephr-registration-form-flex-container{display:flex}.zephr-registration-form-input.svelte-blfh8x{display:block;width:100%;height:calc(var(–zephr-input-height) * 1px);padding-left:8px;font-size:16px;border:calc(var(–zephr-input-borderWidth) * 1px) solid var(–zephr-input-borderColor);border-radius:calc(var(–zephr-input-borderRadius) * 1px);transition:border-color 0.25s ease, box-shadow 0.25s ease;outline:0;color:var(–zephr-color-text-main);background-color:#fff;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-input.svelte-blfh8x::placeholder{color:var(–zephr-color-background-tinted)}.zephr-registration-form-input-checkbox.svelte-blfh8x{width:auto;height:auto;margin:8px 5px 0 0;float:left}.zephr-registration-form-input-radio.svelte-blfh8x{position:absolute;opacity:0;cursor:pointer;height:0;width:0}.zephr-registration-form-input-color[type=”color”].svelte-blfh8x{width:50px;padding:0;border-radius:50%}.zephr-registration-form-input-color[type=”color”].svelte-blfh8x::-webkit-color-swatch{border:none;border-radius:50%;padding:0}.zephr-registration-form-input-color[type=”color”].svelte-blfh8x::-webkit-color-swatch-wrapper{border:none;border-radius:50%;padding:0}.zephr-registration-form-input.disabled.svelte-blfh8x,.zephr-registration-form-input.disabled.svelte-blfh8x:hover{border:calc(var(–zephr-input-borderWidth) * 1px) solid var(–zephr-input-borderColor);background-color:var(–zephr-color-background-tinted)}.zephr-registration-form-input.error.svelte-blfh8x{border:1px solid var(–zephr-color-warning-main)}.zephr-registration-form-input-label.svelte-1ok5fdj.svelte-1ok5fdj{margin-top:10px;display:block;line-height:30px;font-size:12px;color:var(–zephr-color-text-tinted);font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-input-label.svelte-1ok5fdj span.svelte-1ok5fdj{display:block}.zephr-registration-form-button.svelte-17g75t9{height:calc(var(–zephr-button-height) * 1px);line-height:0;padding:0 20px;text-decoration:none;text-transform:capitalize;text-align:center;border-radius:calc(var(–zephr-button-borderRadius) * 1px);font-size:calc(var(–zephr-button-fontSize) * 1px);font-weight:normal;cursor:pointer;border-style:solid;border-width:calc(var(–zephr-button-borderWidth) * 1px);border-color:var(–zephr-color-action-tinted);transition:backdrop-filter 0.2s, background-color 0.2s;margin-top:20px;display:block;width:100%;background-color:var(–zephr-color-action-main);color:#fff;position:relative;overflow:hidden;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-button.svelte-17g75t9:hover{background-color:var(–zephr-color-action-tinted);border-color:var(–zephr-color-action-tinted)}.zephr-registration-form-button.svelte-17g75t9:disabled{background-color:var(–zephr-color-background-tinted);border-color:var(–zephr-color-background-tinted)}.zephr-registration-form-button.svelte-17g75t9:disabled:hover{background-color:var(–zephr-color-background-tinted);border-color:var(–zephr-color-background-tinted)}.zephr-registration-form-text.svelte-i1fi5{font-size:19px;text-align:center;margin:20px auto;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-divider-container.svelte-mk4m8o{display:flex;align-items:center;justify-content:center;margin:40px 0}.zephr-registration-form-divider-line.svelte-mk4m8o{height:1px;width:50%;margin:0 5px;background-color:var(–zephr-color-text-tinted);;}.zephr-registration-form-divider-text.svelte-mk4m8o{margin:0 12px;color:var(–zephr-color-text-main);font-size:14px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);white-space:nowrap}.zephr-registration-form-input-inner-text.svelte-lvlpcn{cursor:pointer;position:absolute;top:50%;transform:translateY(-50%);right:10px;color:var(–zephr-color-text-main);font-size:12px;font-weight:bold;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-response-message.svelte-179421u{text-align:center;padding:10px 30px;border-radius:5px;font-size:15px;margin-top:10px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-response-message-title.svelte-179421u{font-weight:bold;margin-bottom:10px}.zephr-registration-form-response-message-success.svelte-179421u{background-color:#baecbb;border:1px solid #00bc05}.zephr-registration-form-response-message-error.svelte-179421u{background-color:#fcdbec;border:1px solid #d90c00}.zephr-registration-form-social-sign-in.svelte-gp4ky7{align-items:center}.zephr-registration-form-social-sign-in-button.svelte-gp4ky7{height:55px;padding:0 15px;color:#000;background-color:#fff;box-shadow:0px 0px 5px rgba(0, 0, 0, 0.3);border-radius:10px;font-size:17px;display:flex;align-items:center;cursor:pointer;margin-top:20px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-social-sign-in-button.svelte-gp4ky7:hover{background-color:#fafafa}.zephr-registration-form-social-sign-in-icon.svelte-gp4ky7{display:flex;justify-content:center;margin-right:30px;width:25px}.zephr-form-link-message.svelte-rt4jae{margin:10px 0 10px 20px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-recaptcha-tcs.svelte-1wyy3bx{margin:20px 0 0 0;font-size:15px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-recaptcha-inline.svelte-1wyy3bx{margin:20px 0 0 0}.zephr-registration-form-progress-bar.svelte-8qyhcl{width:100%;border:0;border-radius:20px;margin-top:10px}.zephr-registration-form-progress-bar.svelte-8qyhcl::-webkit-progress-bar{background-color:var(–zephr-color-background-tinted);border:0;border-radius:20px}.zephr-registration-form-progress-bar.svelte-8qyhcl::-webkit-progress-value{background-color:var(–zephr-color-text-tinted);border:0;border-radius:20px}.zephr-registration-progress-bar-step.svelte-8qyhcl{margin:auto;color:var(–zephr-color-text-tinted);font-size:12px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-progress-bar-step.svelte-8qyhcl:first-child{margin-left:0}.zephr-registration-progress-bar-step.svelte-8qyhcl:last-child{margin-right:0}.zephr-registration-form-input-error-text.svelte-19a73pq{color:var(–zephr-color-warning-main);font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-input-select.svelte-19a73pq{display:block;appearance:auto;width:100%;height:calc(var(–zephr-input-height) * 1px);font-size:16px;border:calc(var(–zephr-input-borderWidth) * 1px) solid var(–zephr-color-text-main);border-radius:calc(var(–zephr-input-borderRadius) * 1px);transition:border-color 0.25s ease, box-shadow 0.25s ease;outline:0;color:var(–zephr-color-text-main);background-color:#fff;padding:10px}.zephr-registration-form-input-select.disabled.svelte-19a73pq{border:1px solid var(–zephr-color-background-tinted)}.zephr-registration-form-input-select.unselected.svelte-19a73pq{color:var(–zephr-color-background-tinted)}.zephr-registration-form-input-select.error.svelte-19a73pq{border-color:var(–zephr-color-warning-main)}.zephr-registration-form-input-textarea.svelte-19a73pq{background-color:#fff;border:1px solid #ddd;color:#222;font-size:14px;font-weight:300;padding:16px;width:100%}.zephr-registration-form-input-slider-output.svelte-19a73pq{margin:13px 0 0 10px}.zephr-registration-form-input-inner-text.svelte-lvlpcn{cursor:pointer;position:absolute;top:50%;transform:translateY(-50%);right:10px;color:var(–zephr-color-text-main);font-size:12px;font-weight:bold;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.spin.svelte-1cj2gr0{animation:svelte-1cj2gr0-spin 2s 0s infinite linear}.pulse.svelte-1cj2gr0{animation:svelte-1cj2gr0-spin 1s infinite steps(8)}@keyframes svelte-1cj2gr0-spin{0%{transform:rotate(0deg)}100%{transform:rotate(360deg)}}.zephr-registration-form-checkbox.svelte-1gzpw2y{position:absolute;opacity:0;cursor:pointer;height:0;width:0}.zephr-registration-form-checkbox-label.svelte-1gzpw2y{display:flex;align-items:center;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-checkmark.svelte-1gzpw2y{position:relative;box-sizing:border-box;height:23px;width:23px;background-color:#fff;border:1px solid var(–zephr-color-text-main);border-radius:6px;margin-right:12px;cursor:pointer}.zephr-registration-form-checkmark.checked.svelte-1gzpw2y{border-color:#009fe3}.zephr-registration-form-checkmark.checked.svelte-1gzpw2y:after{content:””;position:absolute;width:6px;height:13px;border:solid #009fe3;border-width:0 2px 2px 0;transform:rotate(45deg);top:3px;left:8px;box-sizing:border-box}.zephr-registration-form-checkmark.disabled.svelte-1gzpw2y{border:1px solid var(–zephr-color-background-tinted)}.zephr-registration-form-checkmark.disabled.checked.svelte-1gzpw2y:after{border:solid var(–zephr-color-background-tinted);border-width:0 2px 2px 0}.zephr-registration-form-checkmark.error.svelte-1gzpw2y{border:1px solid var(–zephr-color-warning-main)}.zephr-registration-form-input-radio.svelte-1qn5n0t{position:absolute;opacity:0;cursor:pointer;height:0;width:0}.zephr-registration-form-radio-label.svelte-1qn5n0t{display:flex;align-items:center;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-radio-dot.svelte-1qn5n0t{position:relative;box-sizing:border-box;height:23px;width:23px;background-color:#fff;border:1px solid #ebebeb;border-radius:50%;margin-right:12px}.checked.svelte-1qn5n0t{border-color:#009fe3}.checked.svelte-1qn5n0t:after{content:””;position:absolute;width:17px;height:17px;background:#009fe3;background:linear-gradient(#009fe3, #006cb5);border-radius:50%;top:2px;left:2px}.disabled.checked.svelte-1qn5n0t:after{background:var(–zephr-color-background-tinted)}.error.svelte-1qn5n0t{border:1px solid var(–zephr-color-warning-main)}.zephr-form-link.svelte-64wplc{margin:10px 0;color:#6ba5e9;text-decoration:underline;cursor:pointer;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-form-link-disabled.svelte-64wplc{color:var(–zephr-color-text-main);cursor:none;text-decoration:none}.zephr-registration-form-google-icon.svelte-1jnblvg{width:20px}.zephr-registration-form-password-progress.svelte-d1zv9r{display:flex;margin-top:10px}.zephr-registration-form-password-bar.svelte-d1zv9r{width:100%;height:4px;border-radius:2px}.zephr-registration-form-password-bar.svelte-d1zv9r:not(:first-child){margin-left:8px}.zephr-registration-form-password-requirements.svelte-d1zv9r{margin:20px 0;justify-content:center}.zephr-registration-form-password-requirement.svelte-d1zv9r{display:flex;align-items:center;color:var(–zephr-color-text-tinted);font-size:12px;height:20px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-password-requirement-icon.svelte-d1zv9r{margin-right:10px;font-size:15px}.zephr-registration-form-password-progress.svelte-d1zv9r{display:flex;margin-top:10px}.zephr-registration-form-password-bar.svelte-d1zv9r{width:100%;height:4px;border-radius:2px}.zephr-registration-form-password-bar.svelte-d1zv9r:not(:first-child){margin-left:8px}.zephr-registration-form-password-requirements.svelte-d1zv9r{margin:20px 0;justify-content:center}.zephr-registration-form-password-requirement.svelte-d1zv9r{display:flex;align-items:center;color:var(–zephr-color-text-tinted);font-size:12px;height:20px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-password-requirement-icon.svelte-d1zv9r{margin-right:10px;font-size:15px}
.zephr-registration-form {
max-width: 100%;
background-image: url(/wp-content/themes/sciencenews/client/src/images/cta-module@2x.jpg);
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
margin: 0px auto;
margin-bottom: 4rem;
padding: 20px;
}.zephr-registration-form-text h6 {
font-size: 0.8rem;
}.zephr-registration-form h4 {
font-size: 3rem;
}.zephr-registration-form h4 {
font-size: 1.5rem;
}.zephr-registration-form-button.svelte-17g75t9:hover {
background-color: #fc6a65;
border-color: #fc6a65;
width: 150px;
margin-left: auto;
margin-right: auto;
}
.zephr-registration-form-button.svelte-17g75t9:disabled {
background-color: #e04821;
border-color: #e04821;
width: 150px;
margin-left: auto;
margin-right: auto;
}
.zephr-registration-form-button.svelte-17g75t9 {
background-color: #e04821;
border-color: #e04821;
width: 150px;
margin-left: auto;
margin-right: auto;
}
.zephr-registration-form-text > * {
color: #FFFFFF;
font-weight: bold
font: 25px;
}
.zephr-registration-form-progress-bar.svelte-8qyhcl {
width: 100%;
border: 0;
border-radius: 20px;
margin-top: 10px;
display: none;
}
.zephr-registration-form-response-message-title.svelte-179421u {
font-weight: bold;
margin-bottom: 10px;
display: none;
}
.zephr-registration-form-response-message-success.svelte-179421u {
background-color: #8db869;
border: 1px solid #8db869;
color: white;
margin-top: -0.2rem;
}
.zephr-registration-form-text.svelte-i1fi5:nth-child(1){
font-size: 18px;
text-align: center;
margin: 20px auto;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
}
.zephr-registration-form-text.svelte-i1fi5:nth-child(5){
font-size: 18px;
text-align: left;
margin: 20px auto;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
}
.zephr-registration-form-text.svelte-i1fi5:nth-child(7){
font-size: 18px;
text-align: left;
margin: 20px auto;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
}
.zephr-registration-form-text.svelte-i1fi5:nth-child(9){
font-size: 18px;
text-align: left;
margin: 20px auto;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
}
.zephr-registration-form-input-label.svelte-1ok5fdj span.svelte-1ok5fdj {
display: none;
color: white;
}
.zephr-registration-form-input.disabled.svelte-blfh8x, .zephr-registration-form-input.disabled.svelte-blfh8x:hover {
border: calc(var(–zephr-input-borderWidth) * 1px) solid var(–zephr-input-borderColor);
background-color: white;
}
.zephr-registration-form-checkbox-label.svelte-1gzpw2y {
display: flex;
align-items: center;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
font-size: 20px;
margin-bottom: -20px;
}A second type, incoherent waves, are expected to come from stellar explosions like supernovas (SN: 5/6/19). Because those bursts are spherically symmetrical and relatively slow, their waves are difficult for LIGO to detect. They’re more analogous to individual instruments playing different songs at the same time.
Gottlieb and colleagues considered another type of stellar death called a collapsar. When massive stars collapse into a black hole, they can emit jets of material traveling close to the speed of light. Computer simulations of how those jets form revealed a cocoon of material surrounding the jet, full of hot, turbulent gas and debris that expand in an asymmetric bubble around the dying star, says Gottlieb, who presented the research June 6.
As the bubble expands and pushes its way through the star, it could bump spacetime enough to produce incoherent gravitational waves, Gottlieb and colleagues concluded.
[embedded content]
As a massive star collapses, it emits jets of material (red) and a cocoon of other debris around the jets (yellow and green). This simulation shows how the turbulence in the jets and cocoon could shake spacetime, and translates the gravitational waves they might emit into sound.LIGO and its fellow detectors — Virgo in Italy and KAGRA in Japan — currently have about a 1 percent chance of detecting cocoon gravitational waves. In future runs with improved detectors, that chance will go up.
Catching these waves could give astronomers a glimpse into the innermost parts of dying stars, which can’t be studied any other way, Gottlieb said. More
Mercury’s auroras are perfectly in character. While temperate Earth gets heavenly light shows over its poles, hellish Mercury gets invisible ribbons of X-ray radiation that cling to its sun-blasted surface.
But as alien as they may appear, Mercury’s X-ray auroras have a lot in common with Earth’s polar lights, and with auroras throughout the solar system.
Scientists have now directly shown that fluctuations in Mercury’s magnetic field can fling electrons toward the planet, where they eventually rain down and cause auroras of X-ray light. This process, called electron precipitation, now appears to be practically universal in the solar system: It causes auroras on every planet with a global magnetic field except Neptune, researchers report July 18 in Nature Communications. Even Mars, which has only localized magnetic fields, has auroras caused by raining electrons (SN: 3/19/15).
.email-conversion {
border: 1px solid #ffcccb;
color: white;
margin-top: 50px;
background-image: url(“/wp-content/themes/sciencenews/client/src/images/cta-module@2x.jpg”);
padding: 20px;
clear: both;
}.zephr-registration-form{max-width:440px;margin:20px auto;padding:20px;background-color:#fff;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form *{box-sizing:border-box}.zephr-registration-form-text > *{color:var(–zephr-color-text-main)}.zephr-registration-form-relative-container{position:relative}.zephr-registration-form-flex-container{display:flex}.zephr-registration-form-input.svelte-blfh8x{display:block;width:100%;height:calc(var(–zephr-input-height) * 1px);padding-left:8px;font-size:16px;border:calc(var(–zephr-input-borderWidth) * 1px) solid var(–zephr-input-borderColor);border-radius:calc(var(–zephr-input-borderRadius) * 1px);transition:border-color 0.25s ease, box-shadow 0.25s ease;outline:0;color:var(–zephr-color-text-main);background-color:#fff;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-input.svelte-blfh8x::placeholder{color:var(–zephr-color-background-tinted)}.zephr-registration-form-input-checkbox.svelte-blfh8x{width:auto;height:auto;margin:8px 5px 0 0;float:left}.zephr-registration-form-input-radio.svelte-blfh8x{position:absolute;opacity:0;cursor:pointer;height:0;width:0}.zephr-registration-form-input-color[type=”color”].svelte-blfh8x{width:50px;padding:0;border-radius:50%}.zephr-registration-form-input-color[type=”color”].svelte-blfh8x::-webkit-color-swatch{border:none;border-radius:50%;padding:0}.zephr-registration-form-input-color[type=”color”].svelte-blfh8x::-webkit-color-swatch-wrapper{border:none;border-radius:50%;padding:0}.zephr-registration-form-input.disabled.svelte-blfh8x,.zephr-registration-form-input.disabled.svelte-blfh8x:hover{border:calc(var(–zephr-input-borderWidth) * 1px) solid var(–zephr-input-borderColor);background-color:var(–zephr-color-background-tinted)}.zephr-registration-form-input.error.svelte-blfh8x{border:1px solid var(–zephr-color-warning-main)}.zephr-registration-form-input-label.svelte-1ok5fdj.svelte-1ok5fdj{margin-top:10px;display:block;line-height:30px;font-size:12px;color:var(–zephr-color-text-tinted);font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-input-label.svelte-1ok5fdj span.svelte-1ok5fdj{display:block}.zephr-registration-form-button.svelte-17g75t9{height:calc(var(–zephr-button-height) * 1px);line-height:0;padding:0 20px;text-decoration:none;text-transform:capitalize;text-align:center;border-radius:calc(var(–zephr-button-borderRadius) * 1px);font-size:calc(var(–zephr-button-fontSize) * 1px);font-weight:normal;cursor:pointer;border-style:solid;border-width:calc(var(–zephr-button-borderWidth) * 1px);border-color:var(–zephr-color-action-tinted);transition:backdrop-filter 0.2s, background-color 0.2s;margin-top:20px;display:block;width:100%;background-color:var(–zephr-color-action-main);color:#fff;position:relative;overflow:hidden;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-button.svelte-17g75t9:hover{background-color:var(–zephr-color-action-tinted);border-color:var(–zephr-color-action-tinted)}.zephr-registration-form-button.svelte-17g75t9:disabled{background-color:var(–zephr-color-background-tinted);border-color:var(–zephr-color-background-tinted)}.zephr-registration-form-button.svelte-17g75t9:disabled:hover{background-color:var(–zephr-color-background-tinted);border-color:var(–zephr-color-background-tinted)}.zephr-registration-form-text.svelte-i1fi5{font-size:19px;text-align:center;margin:20px auto;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-divider-container.svelte-mk4m8o{display:flex;align-items:center;justify-content:center;margin:40px 0}.zephr-registration-form-divider-line.svelte-mk4m8o{height:1px;width:50%;margin:0 5px;background-color:var(–zephr-color-text-tinted);;}.zephr-registration-form-divider-text.svelte-mk4m8o{margin:0 12px;color:var(–zephr-color-text-main);font-size:14px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);white-space:nowrap}.zephr-registration-form-input-inner-text.svelte-lvlpcn{cursor:pointer;position:absolute;top:50%;transform:translateY(-50%);right:10px;color:var(–zephr-color-text-main);font-size:12px;font-weight:bold;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-response-message.svelte-179421u{text-align:center;padding:10px 30px;border-radius:5px;font-size:15px;margin-top:10px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-response-message-title.svelte-179421u{font-weight:bold;margin-bottom:10px}.zephr-registration-form-response-message-success.svelte-179421u{background-color:#baecbb;border:1px solid #00bc05}.zephr-registration-form-response-message-error.svelte-179421u{background-color:#fcdbec;border:1px solid #d90c00}.zephr-registration-form-social-sign-in.svelte-gp4ky7{align-items:center}.zephr-registration-form-social-sign-in-button.svelte-gp4ky7{height:55px;padding:0 15px;color:#000;background-color:#fff;box-shadow:0px 0px 5px rgba(0, 0, 0, 0.3);border-radius:10px;font-size:17px;display:flex;align-items:center;cursor:pointer;margin-top:20px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-social-sign-in-button.svelte-gp4ky7:hover{background-color:#fafafa}.zephr-registration-form-social-sign-in-icon.svelte-gp4ky7{display:flex;justify-content:center;margin-right:30px;width:25px}.zephr-form-link-message.svelte-rt4jae{margin:10px 0 10px 20px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-recaptcha-tcs.svelte-1wyy3bx{margin:20px 0 0 0;font-size:15px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-recaptcha-inline.svelte-1wyy3bx{margin:20px 0 0 0}.zephr-registration-form-progress-bar.svelte-8qyhcl{width:100%;border:0;border-radius:20px;margin-top:10px}.zephr-registration-form-progress-bar.svelte-8qyhcl::-webkit-progress-bar{background-color:var(–zephr-color-background-tinted);border:0;border-radius:20px}.zephr-registration-form-progress-bar.svelte-8qyhcl::-webkit-progress-value{background-color:var(–zephr-color-text-tinted);border:0;border-radius:20px}.zephr-registration-progress-bar-step.svelte-8qyhcl{margin:auto;color:var(–zephr-color-text-tinted);font-size:12px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-progress-bar-step.svelte-8qyhcl:first-child{margin-left:0}.zephr-registration-progress-bar-step.svelte-8qyhcl:last-child{margin-right:0}.zephr-registration-form-input-error-text.svelte-19a73pq{color:var(–zephr-color-warning-main);font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-input-select.svelte-19a73pq{display:block;appearance:auto;width:100%;height:calc(var(–zephr-input-height) * 1px);font-size:16px;border:calc(var(–zephr-input-borderWidth) * 1px) solid var(–zephr-color-text-main);border-radius:calc(var(–zephr-input-borderRadius) * 1px);transition:border-color 0.25s ease, box-shadow 0.25s ease;outline:0;color:var(–zephr-color-text-main);background-color:#fff;padding:10px}.zephr-registration-form-input-select.disabled.svelte-19a73pq{border:1px solid var(–zephr-color-background-tinted)}.zephr-registration-form-input-select.unselected.svelte-19a73pq{color:var(–zephr-color-background-tinted)}.zephr-registration-form-input-select.error.svelte-19a73pq{border-color:var(–zephr-color-warning-main)}.zephr-registration-form-input-textarea.svelte-19a73pq{background-color:#fff;border:1px solid #ddd;color:#222;font-size:14px;font-weight:300;padding:16px;width:100%}.zephr-registration-form-input-slider-output.svelte-19a73pq{margin:13px 0 0 10px}.zephr-registration-form-input-inner-text.svelte-lvlpcn{cursor:pointer;position:absolute;top:50%;transform:translateY(-50%);right:10px;color:var(–zephr-color-text-main);font-size:12px;font-weight:bold;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.spin.svelte-1cj2gr0{animation:svelte-1cj2gr0-spin 2s 0s infinite linear}.pulse.svelte-1cj2gr0{animation:svelte-1cj2gr0-spin 1s infinite steps(8)}@keyframes svelte-1cj2gr0-spin{0%{transform:rotate(0deg)}100%{transform:rotate(360deg)}}.zephr-registration-form-checkbox.svelte-1gzpw2y{position:absolute;opacity:0;cursor:pointer;height:0;width:0}.zephr-registration-form-checkbox-label.svelte-1gzpw2y{display:flex;align-items:center;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-checkmark.svelte-1gzpw2y{position:relative;box-sizing:border-box;height:23px;width:23px;background-color:#fff;border:1px solid var(–zephr-color-text-main);border-radius:6px;margin-right:12px;cursor:pointer}.zephr-registration-form-checkmark.checked.svelte-1gzpw2y{border-color:#009fe3}.zephr-registration-form-checkmark.checked.svelte-1gzpw2y:after{content:””;position:absolute;width:6px;height:13px;border:solid #009fe3;border-width:0 2px 2px 0;transform:rotate(45deg);top:3px;left:8px;box-sizing:border-box}.zephr-registration-form-checkmark.disabled.svelte-1gzpw2y{border:1px solid var(–zephr-color-background-tinted)}.zephr-registration-form-checkmark.disabled.checked.svelte-1gzpw2y:after{border:solid var(–zephr-color-background-tinted);border-width:0 2px 2px 0}.zephr-registration-form-checkmark.error.svelte-1gzpw2y{border:1px solid var(–zephr-color-warning-main)}.zephr-registration-form-input-radio.svelte-1qn5n0t{position:absolute;opacity:0;cursor:pointer;height:0;width:0}.zephr-registration-form-radio-label.svelte-1qn5n0t{display:flex;align-items:center;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-radio-dot.svelte-1qn5n0t{position:relative;box-sizing:border-box;height:23px;width:23px;background-color:#fff;border:1px solid #ebebeb;border-radius:50%;margin-right:12px}.checked.svelte-1qn5n0t{border-color:#009fe3}.checked.svelte-1qn5n0t:after{content:””;position:absolute;width:17px;height:17px;background:#009fe3;background:linear-gradient(#009fe3, #006cb5);border-radius:50%;top:2px;left:2px}.disabled.checked.svelte-1qn5n0t:after{background:var(–zephr-color-background-tinted)}.error.svelte-1qn5n0t{border:1px solid var(–zephr-color-warning-main)}.zephr-form-link.svelte-64wplc{margin:10px 0;color:#6ba5e9;text-decoration:underline;cursor:pointer;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-form-link-disabled.svelte-64wplc{color:var(–zephr-color-text-main);cursor:none;text-decoration:none}.zephr-registration-form-google-icon.svelte-1jnblvg{width:20px}.zephr-registration-form-password-progress.svelte-d1zv9r{display:flex;margin-top:10px}.zephr-registration-form-password-bar.svelte-d1zv9r{width:100%;height:4px;border-radius:2px}.zephr-registration-form-password-bar.svelte-d1zv9r:not(:first-child){margin-left:8px}.zephr-registration-form-password-requirements.svelte-d1zv9r{margin:20px 0;justify-content:center}.zephr-registration-form-password-requirement.svelte-d1zv9r{display:flex;align-items:center;color:var(–zephr-color-text-tinted);font-size:12px;height:20px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-password-requirement-icon.svelte-d1zv9r{margin-right:10px;font-size:15px}.zephr-registration-form-password-progress.svelte-d1zv9r{display:flex;margin-top:10px}.zephr-registration-form-password-bar.svelte-d1zv9r{width:100%;height:4px;border-radius:2px}.zephr-registration-form-password-bar.svelte-d1zv9r:not(:first-child){margin-left:8px}.zephr-registration-form-password-requirements.svelte-d1zv9r{margin:20px 0;justify-content:center}.zephr-registration-form-password-requirement.svelte-d1zv9r{display:flex;align-items:center;color:var(–zephr-color-text-tinted);font-size:12px;height:20px;font-family:var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont)}.zephr-registration-form-password-requirement-icon.svelte-d1zv9r{margin-right:10px;font-size:15px}
.zephr-registration-form {
max-width: 100%;
background-image: url(https://www.sciencenews.org/wp-content/uploads/2023/05/newsletter-signup-background_REV.jpg);
background-position: top 75% left 67%;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
margin: 0px auto;
margin-bottom: 4rem;
padding: 20px;
}.zephr-registration-form-text.svelte-i1fi5 p {
padding-left: 10px;
padding-right: 10px;
padding-bottom: 10px;
}.zephr-registration-form-text.svelte-i1fi5 h2 {
padding-top: 10px;
}.zephr-registration-form-text h6 {
font-size: 0.8rem;
}.zephr-registration-form h4 {
font-size: 3rem;
}.zephr-registration-form h4 {
font-size: 1.5rem;
}.zephr-registration-form-button.svelte-17g75t9:hover {
background-color: #fc6a65;
border-color: #fc6a65;
width: 150px;
margin-left: auto;
margin-right: auto;
}
.zephr-registration-form-button.svelte-17g75t9:disabled {
background-color: #e04821;
border-color: #e04821;
width: 150px;
margin-left: auto;
margin-right: auto;
}
.zephr-registration-form-button.svelte-17g75t9 {
background-color: #e04821;
border-color: #e04821;
width: 150px;
margin-left: auto;
margin-right: auto;
}
.zephr-registration-form-text > * {
color: #FFFFFF;
font-weight: bold
font: 25px;
background-color: rgba(10,10,10,0.7)
}
.zephr-registration-form-progress-bar.svelte-8qyhcl {
width: 100%;
border: 0;
border-radius: 20px;
margin-top: 10px;
display: none;
}
.zephr-registration-form-response-message-title.svelte-179421u {
font-weight: bold;
margin-bottom: 10px;
display: none;
}
.zephr-registration-form-response-message-success.svelte-179421u {
background-color: #8db869;
border: 1px solid #8db869;
color: white;
margin-top: -0.2rem;
}
.zephr-registration-form-text.svelte-i1fi5:nth-child(1){
font-size: 18px;
text-align: center;
margin: 20px auto;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
}
.zephr-registration-form-text.svelte-i1fi5:nth-child(5){
font-size: 18px;
text-align: left;
margin: 20px auto;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
}
.zephr-registration-form-text.svelte-i1fi5:nth-child(7){
font-size: 18px;
text-align: left;
margin: 20px auto;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
}
.zephr-registration-form-text.svelte-i1fi5:nth-child(9){
font-size: 18px;
text-align: left;
margin: 20px auto;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
}
.zephr-registration-form-input-label.svelte-1ok5fdj span.svelte-1ok5fdj {
display: none;
color: white;
}
.zephr-registration-form-input.disabled.svelte-blfh8x, .zephr-registration-form-input.disabled.svelte-blfh8x:hover {
border: calc(var(–zephr-input-borderWidth) * 1px) solid var(–zephr-input-borderColor);
background-color: white;
}
.zephr-registration-form-checkbox-label.svelte-1gzpw2y {
display: flex;
align-items: center;
font-family: var(–zephr-typography-body-font), var(–zephr-typography-body-fallbackFont);
color: white;
font-size: 20px;
margin-bottom: -20px;
}
.zephr-registration-progress-bar-step.svelte-8qyhcl:first-child {
display: none;
}
.zephr-registration-progress-bar-step.svelte-8qyhcl:last-child {
display: none;
}For Mercury, “this is really the first time to detect these electrons directly,” says space plasma physicist Sae Aizawa of the University of Pisa in Italy.
Electron precipitation usually happens because of interactions between planets’ magnetic fields and the solar wind — a stream of charged particles spewed from the sun’s upper atmosphere.
Buffeted by the solar wind, the sun-facing side of a planet’s magnetic field gets squished while the night side is swept out into a long “magnetotail” that extends behind the planet. Eventually, the magnetotail stretches so much that its formerly mostly-parallel magnetic field lines snap and reconnect, sending some field lines flying off behind the planet and others back toward it.
Part of Mercury’s northern hemisphere comes into view in this picture taken by the BepiColombo probe (parts of which are visible in the foreground) during its first flyby of Mercury in 2021.BepiColombo/MTM/ESA, CC BY-SA 3.0 IGO
“The magnetic field lines sort of break and form new ones,” says space physicist Ryan Dewey of the University of Michigan in Ann Arbor, who was not involved in the study. “And in that process, a lot of energy is released.”
All that energy sends packets of electrons flying planetward, spiraling in corkscrew-like trajectories along magnetic field lines. When these electrons hit the planet or its atmosphere, they release energy as light.
The light’s wavelength depends on what the electrons encounter as they rain down. Earth’s auroras shine in visible wavelengths because incoming electrons excite molecules of uncharged gases in the atmosphere like oxygen and nitrogen, which release visible light when they relax back to their normal states. Mercury’s auroras shine in X-ray wavelengths because electrons decelerate as they smack the planet’s rocky surface. The lost energy is released as X-rays.
Researchers first spotted Mercurian X-ray auroras in data beamed back from the MESSENGER probe, which orbited Mercury from 2011 to 2015 (SN: 4/30/15). But while scientists reasoned that electrons must rain down on Mercury to cause its X-ray glow, MESSENGER didn’t have the right instruments to measure the precipitating particles.
The European Space Agency’s BepiColombo spacecraft does. Analyzing data from the probe’s first flyby of Mercury in 2021, Aizawa and her colleagues spotted telltale signs of the process.
One clue was that as BepiColombo flew through Mercury’s magnetosphere, it observed surges of fast-moving, high-speed electrons followed by several subsequent waves of progressively slower, lower-energy electrons. “This is exactly what we’d describe as a precipitating signature,” says Aizawa, who did the work while at the Institute of Research in Astrophysics and Planetology in Toulouse, France.
.subscribe-cta {
color: black;
margin-top: 0px;
background-image: url(“”);
background-size: cover;
padding: 20px;
border: 1px solid #ffcccb;
border-top: 5px solid #e04821;
clear: both;
}Subscribe to Science News
Get great science journalism, from the most trusted source, delivered to your doorstep.
To Dewey, the new discovery is a tantalizing sneak peek at the discoveries waiting to be made at Mercury once BepiColombo enters orbit in 2025. By then, it will have been a decade since scientists last had a probe continuously orbiting Mercury.
“To me, it’s very exciting to see just how much we can learn from even just a short pass through the magnetosphere,” he says. “It’s a glimpse.” More
