Rebecca Boyle, Author at ��è��Ƶ

How astonishing observatories could do big physics from the moon

Rebecca Boyle — Wed, 23 Apr 2025 15:00:00 +0000

As humanity prepares to return to the moon, scientists also have ideas for huge lunar experiments that could revolutionise astrophysics

Future moon missions probably won’t carry astronauts – here’s why

Rebecca Boyle — Mon, 08 Jul 2019 11:00:00 +0000

Unlike the Apollo missions, the new era of moon exploration might be about mining, tourism or art. The reason we pick to return will define the moon's future

Bright skies at night: The riddle of the nocturnal sun

Rebecca Boyle — Tue, 19 Dec 2017 18:00:00 +0000

Before artificial lights blinded our sight, reports of nights as bright as day were common. What lay behind the phenomenon was a mystery – until now

We may have just seen the first comet from another solar system

Rebecca Boyle — Wed, 25 Oct 2017 21:42:09 +0000

Not from around these parts?

Richard Bizley/Science Photo Library

The solar system may be hosting a visitor from the stars. A newly discovered comet is screaming away from Earth, and based on its weird orbital trajectory astronomers think it might be the first comet ever observed that came from interstellar space.

A sky-surveying telescope in Hawaii spotted the fast-moving object, now called, on 18 October, after its closest approach to the sun. During the next week, astronomers made 34 separate observations of the object and found it has a strange trajectory that is at an angle to the orbits of the planets and does not circle the sun.

Now, astronomers are hoping more skywatchers will take a look and pin down whether it’s from our neighborhood or an interloper from beyond.

Most comets follow ellipse-shaped orbits around the sun, swooping in from the distant Oort Cloud to kiss the inner solar system before heading back out again. This one, by contrast, will never return. Its orbital path suggests it sailed in from the direction of the constellation Lyra above the relatively flat plane of the solar system, looped around the sun, and is headed back out for eternity.

Lyra is near the direction the sun is moving within the Milky Way, says at the Southwest Research Institute in Boulder, Colorado. “That’s exactly what you’d expect; there should be more interstellar comets coming from the direction the sun is heading toward,” he says.

Just popping in

“It’s coming from very far away, but we can’t actually backtrack how far away it started. It could be that it’s coming from outside the solar system, but it’s really hard to tell,” says , also at the Southwest Research Institute. Further observations in the next couple weeks will make the picture clearer.

What’s more, a comet on such an extreme path doesn’t necessarily have to come from interstellar space. “It could have interacted with Jupiter or another planet in such a way that changed its orbit,” says at the University of South Florida in Tampa.

The comet’s origins are hard to pin down in part because of the nature of comets. “When you think of photos of comets, they’re a fuzzy blob. People have to make determinations of where they think the center is. Someone who is at the telescope has to make a call,” Womack says.

This necessary guesswork makes the measurements less precise, so astronomers want lots of observations before they’ll be convinced the comet really is from beyond our solar system, she adds.

Luckily, there are plenty of opportunities left to take a peek. The comet should be visible in powerful telescopes for at least another couple weeks, allowing amateurs and professionals alike to survey the icy visitor and determine its history.

Methane burps on young Mars helped it keep its liquid water

Rebecca Boyle — Mon, 02 Oct 2017 15:00:04 +0000

The rocks on Mars’s surface can tell us what gases were in the air when they were formed

NASA/JPL-Caltech/ASU/UA

Better out than in. Explosive burps of methane flowing into young Mars’s atmosphere might have temporarily warmed the planet, allowing liquid water to persist even after Mars entered its dry period. Rovers and orbiters have found evidence that Mars had rivers 3 billion years ago, suggesting things occasionally warmed up enough for ice to melt and flow as water, sometimes for a million years. The reason might have been giant bursts of methane, a potent greenhouse gas, according to Edwin Kite of the University of Chicago. These methane deposits, which may date to the birth of Mars, could even be responsible for temporary methane burps spotted by modern Mars spacecraft. The methane bursts would have happened as Mars wobbled on its axis. Like Earth, Mars is tilted on its axis, but that tilt can change wildly over time because of relationships between its orbit and that of Jupiter. When Mars was extremely tilted, its ice deposits spent more time in direct sunlight, so they could have melted. This would free methane trapped in the ice crystals. “It’s basically ice that you can set on fire. You can flick a lighter at it, and get a flame,” he says. “In your hand, it looks like ice, but at the pressures at Earth’s surface, it is unstable so it releases methane gas.”

Explosive eruptions

During periods of extreme Martian tilt, the stored methane would explosively erupt into the atmosphere, warming it enough to melt frozen lakes and start rivers flowing. Ultraviolet radiation from the sun would eventually break down the methane, but it could persist for up to a million years, says Kite. The timing and duration of extreme-tilt events matches the duration and relative rarity of lake-forming climates in Mars’s history, his team found. Adding a 1 per cent dose of methane to a carbon dioxide-rich atmosphere, at the same pressure as Earth’s atmosphere, would raise temperatures by 6°C – enough to melt Martian ice. This would only be possible if Mars also had a blanket of CO₂to keep it warm, too, Kite says. The methane would just be an added boost. But recent evidence suggests Mars may not have had as much CO₂as researchers thought.

Missing elements

Thomas Bristow of NASA’s Ames Research Center and his colleagues recently found in rocks Curiosity has been studying inside Gale Crater. “Having a thick CO₂-rich atmosphere leads to some expectations about the kinds of rocks you would find deposited at that time. You would expect to see lots of carbonate minerals around, particularly in sedimentary rocks,” Bristow says, “but we don’t see them.” Does this mean there was indeed low CO₂? Or, that it was somehow sequestered from the lakebed Curiosity is now traversing and may be in rocks we haven’t studied yet? That’s an open question — but “if Tom’s right, I’m wrong”, Kite says. If there was no CO₂, “there would be no net warming at all if you released methane into the atmosphere, because you need the CO₂, too”. The true test for methane may come from the ExoMars Trace Gas Orbiter, a European mission that arrived at Mars last fall. It will begin measuring the Martian atmosphere next spring, Kite says. It may be able to detect faint signals of methane at present, lending heft to the idea that methane burps could have warmed ancient Mars.

Nature Geoscience

Slingshot around Titan is the beginning of the end for Cassini

Rebecca Boyle — Mon, 11 Sep 2017 12:36:03 +0000

Ready for the final plunge

NASA

With Cassini nearing its demise, it will be some time before we can again so closely observe Saturn’s largest moon, Titan. Cassini was built in large part to answer questions about this enigmatic moon, and today Titan will seal its fate.

The probe’s last Titan flyby on 21 April bent Cassini’s orbit to enable it to fly between Saturn and the planet’s rings. Today’s final slingshot past that moon will speed up the spacecraft and set it on an irreversible collision course with Saturn in five days’ time.

Cassini’s Grand Finale:

Join us as we count down to the fiery end of the Cassini spacecraft’s mission to Saturn

“With that final kiss goodbye from Titan, we are going so deep into Saturn’s atmosphere that the spacecraft is not going to have any chance to come back out,” says Earl Maize, Cassini project manager at NASA.

Cassini is taking a last look at the moon and its weather before speeding towards Saturn. Through Cassini’s eyes, scientists have learned that Mercury-sized Titan is a world bathed in liquids, with a hydrological cycle very similar to that of Earth. Hydrocarbons rain from the sky, etching Titan’s surface with rivers, lakes and seas. Methane waves lap on its shores.

“Right now, somewhere on Titan, it is raining. That’s the only place in the solar system where I can say that,” says Alex Hayes at Cornell University in Ithaca, New York.

Titanic landscape

While Cassini carries instruments designed to study the entire Saturn system, it brought along an entire lander just for examining Titan.

The Huygens probe, which landed on Titan in 2005, is the furthest object ever delivered to the surface of another world. It sent back images of a ruddy, mountainous surface, and dark pebbles in what appeared to be a dry lakebed. The probe provided the first direct evidence that Titan experiences rainfall.

Over the years, Cassini’s radar instruments allowed scientists to peer beneath Titan’s hazy atmosphere and study its surface and lakes, which they found are made of liquid methane and ethane. Methane is common on Earth but breaks down quickly, so its abundance on Titan was surprising and remains hard for scientists to explain. It is often a byproduct of life, but could also provide energy to sustain strange forms of life unimagined on Earth.

Saturn and Titan

NASA/JPL-Caltech/Space Science Institute

In addition, Cassini unveiled mountains and dunes that are much like sand dunes on Earth, but that scientists think are made of hydrocarbon-coated ice pebbles. Evidence even emerged that Titan may harbour an internal ocean of liquid water and ammonia.

“We now know that there is another world in the solar system that has abundant liquids and organics, and therefore harbours the potential for life,” said Sarah Hörst at Johns Hopkins University in Baltimore, Maryland, in a recent editorial published in Nature Astronomy.

Placing bets

Hayes says he often tells a story of a friendly betting pool that scientists shared before Huygens landed, when researchers scrawled their choices of what the probe would encounter on a bulletin board at Caltech in Pasadena, California.

Learn more about the missions to explore our solar system:

“People signed up for different categories that included things like ice, tar, liquid, or dead on arrival; one scientist made his own category and called it ‘eaten by a sea monster’,” he says.

“‘What is Huygens going to land on?’ is the story of Titan. Every time we learn something new, another series of just-as-interesting questions crops up as a result of that new knowledge. That’s been the paradigm of Titan exploration for the past 13 years with Cassini.”

The next decade is much less certain. Although a couple of Titan missions are in the early stages of planning, none are imminent. So once Cassini sails to its certain doom, we may only have its data to pore over for some time.

Stripy ponds in the Utah desert help green the bone-dry land

Rebecca Boyle — Wed, 06 Sep 2017 18:00:00 +0000

PATCHWORK ponds catch the eye in this image of the Utah desert taken by an astronaut from the International Space Station. The brilliant blues will eventually produce landscapes of vivid green. When the pond water evaporates, it will leave potassium salt, a vital fertiliser. The 23 coloured ponds cover 160 hectares, and play a key part in the mining of potassium chloride from ore buried underground. The compound, otherwise known as muriate of potash, accounts for 95 per cent of all potash fertilisers used worldwide. Each pond is full of potash brine, and the colour reflects its state of evaporation. The darkest blue indicates deeper water, but it’s also this shade for another reason: the rich blue hue comes from dye added to speed up the rate at which the water absorbs sunlight and warmth, aiding evaporation. Lighter blues and sea-foam greens indicate ponds with shallower water and less dye. The tan ponds are dry, with just a layer of potassium salt crystals left. The ponds contrast with the high desert of the Colorado plateau, which sits 1600 metres above sea level. The darker green areas along the river are the only lush vegetation in the picture. This article appeared in print under the headline “True blue”

Asteroid Florence buzzes Earth in closest fly-by since 1890

Rebecca Boyle — Mon, 04 Sep 2017 15:16:33 +0000

A giant rock named after Florence Nightingale whizzed past Earth on 1 September

NASA

A huge space rock named Florence, roughly 4.4 kilometres across, whizzed past Earth at a relatively close 7 million kilometres on 1 September. It is the biggest asteroid to fly near Earth in more than a century.

Astronomers discovered the asteroid in 1981 and named it for Florence Nightingale, the founder of modern nursing. Based on a reconstruction of its historical orbit, astronomers have determined that this fly-by is the closest Florence has come to Earth since 1890. It’s also the biggest asteroid we’ve seen pass this close to Earth since NASA began detecting near-Earth asteroids in 1995.

The rock is highly reflective, as asteroids go, so it was bright enough to be visible in small telescopes for several nights. Astronomers also studied it from Puerto Rico and California using radar imaging. It travelled through the constellations Piscis Austrinus, Capricornus, Aquarius and Delphinus.

Studies announced that radar imaging revealed two moons orbiting Florence. Of the 16,400 near-Earth asteroids discovered, this is only the third triple system ever seen. The moons are between 100 and 300 metres across.

If a rock the size of Florence hit Earth at the speed of the meteor that exploded over Chelyabinsk, Russia, in 2013, it would excavate a crater 55 kilometres across and 1 kilometre deep, and cause catastrophic effects for Earth’s atmosphere and ecosystems.

Luckily, it won’t reach any nearer than 18 times the average distance between Earth and the moon, and it won’t get this close again until after 2500.

Hidden pockets of turbulent gas fuel stars in far-off galaxies

Rebecca Boyle — Wed, 30 Aug 2017 17:40:21 +0000

The Cosmic Eyelash, a remote starburst galaxy, hosts a hidden reservoir of star fuel

ALMA (ESO/NAOJ/NRAO)/E. Falgarone et al.

Gargantuan gas reservoirs have been spotted around multiple distant galaxies, where they can provide fuel for new stars — contrary to accepted theory. A powerful radio telescope in the Chilean desert unmasked the gas, which sheds new light on how galaxies can extend their star-forming eras. The violent births and deaths of stars cause a wind within galaxies, which can eject gas from the galaxy and make it harder for new stars to form. In recent years, scientists have argued that these winds are not powerful enough to push gas beyond a galaxy’s gravitational grasp — but the outflow of gas is thought to play a role in why some galaxies stop making new stars. Now, at the Paris Observatory and colleagues say the winds are doing the opposite. “By driving turbulence in the reservoirs, these galactic winds extend the starburst phase instead of quenching it,” she says. Falgarone and her colleagues used the Atacama Large Millimeter/Sub-millimeter Array to measure a molecule called CH+, also known as methylidynium. The molecule serves as a tracer for the galactic gas, much like dropping ink into a body of water would illuminate its currents. By tracking CH+, Falgarone noticed previously unseen reservoirs of cold gas, which are rocked by turbulence from the galactic winds.

Finding galactic flows

The ALMA observations will benefit supercomputer simulations that are trying to predict these galactic flows, says at the University of North Carolina-Chapel Hill. And the James Webb Space Telescope (JWST), due to launch next year, will also study gas emissions, he says. “JWST spectroscopy can link such flows from the starburst region to large-scale reservoirs,” Cecil says. The reservoir is not filled by galactic winds alone, suggesting the gas is supplied by galactic mergers or other streams of gas that remain hidden. The new results don’t rule out the possibility that these galaxies simply have not yet entered their “star-quenching” phase, says at the University of Maryland. “Perhaps it is just a matter of time until a powerful quasar is turned on and will do real damage to the host galaxy, preventing the turbulent gas from accreting back and forming stars,” Veilleux says.

Nature

Weird ancient burst of light in the sky turns out to be a nova

Rebecca Boyle — Wed, 30 Aug 2017 17:00:16 +0000

Strange light from another star

NASA/CXC/M.Weiss

A 25-year hunt for a bright spot in the sky first seen almost six centuries ago has turned up a nova – and answered a long-standing question about this unique type of exploding star. We now have a better idea of what they do between more intense periods of activity.

Royal astronomers working in the court of King Sejong the Great of Korea noticed something unusual shining in the sky on 11 March 1437.

“A guest star began to be seen between the second and third stars of Wei,” an astronomer recorded – Wei being a collection of nine stars in the tail of the constellation Scorpius. “It lasted for 14 days.”

Now, at the American Museum of Natural History in New York has discovered the origin of this “guest star”. It was previously a classical nova, a unique type of stellar explosion, and now exhibits dwarf nova behaviour.

Repeating explosions

Shara found that binary star systems with classical nova and dwarf nova eruptions are in fact the same systems, just seen at different times in their lives.

Classical novae are not the same as supernovae, the death gasp of stars. They are more like a thermonuclear bomb going off on a star’s surface, says Shara, and happen in binary star systems that include a white dwarf accompanied by a nearby red giant or red dwarf.

The white dwarf pulls hydrogen away from its neighbour, and when enough hydrogen piles up, the gas can get hot enough to trigger nuclear fusion. Eventually, the gas layer explodes and is ejected from the star, resulting in a nova. This cycle repeats itself over a period of several months to several thousand years.

Classical novae can shine a million times brighter than the sun, but do not persist for long. Because the Korean astronomers noted that the ancient nova disappeared in just two weeks, Shara suspected this must have been what they saw.

He has been searching for evidence of it for more than 25 years. “We absolutely scoured that part of Scorpius, and came up with nothing,” he says.

Widening the search

About a year and a half ago, Shara expanded his search using digitised sky survey records and data from telescopes that observe the universe in different parts of the light spectrum. He included two additional Scorpius stars in his search, and found what he was looking for in a matter of minutes: a star with a nearby shell of hot gas.

“It was just one of those moments where you take the palm of your hand and whack it against your forehead,” he says.

Shara and his colleagues then used archival photographic plates from the Digital Access to a Sky Century at Harvard, a collection of astronomical survey photos dating back more than 100 years. The team saw that the nova had erupted again in 1923 and 1942, and noticed other smaller explosions in the 1930s that were dwarf novae rather than classical ones.

This suggests that these nova-producing systems generate smaller explosions between their repeating classical novae. The finding settles a debate about what these stars are doing in the intervals between novae, says at the University of Pisa in Italy.

“Astronomy is concerned with both the large scale and the long term,” he writes in an editorial, “and historical observations are often important for resolving evolutionary questions.”

Journal reference: Nature, DOI:

Rebecca Boyle, Author at ��è����Ƶ