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The Red Planet launches large bursts of plasma into space from its upper atmosphere, much like the sun’s coronal mass ejections, despite not having a global magnetic field
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Tag: solar system
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Mars is blasting plasma out of its atmosphere into space
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How could we make a solar eclipse happen every day?
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Dead Planets Society is a podcast that takes outlandish ideas about how to tinker with the cosmos – from snapping the moon in half to causing a gravitational wave apocalypse – and subjects them to the laws of physics to see how they fare. Listen on Apple, Spotify or on our podcast page.
A total solar eclipse is one of the most incredible cosmic events we can witness from Earth – but they can also be inconvenient. Any particular location only experiences a solar eclipse about once every few hundred years or so, and travelling to the path of totality isn’t always feasible.
In this episode of Dead Planets Society, hosts Leah Crane and Chelsea Whyte are joined by astronomer Bruce Macintosh at the University of California, Santa Cruz, in their attempts to fix this problem and conjure up a total solar eclipse that is accessible to all.
Natural solar eclipses occur when the moon passes in front of the sun, casting a shadow on Earth’s surface. To create an artificial eclipse, our hosts will have to put something else between Earth and the sun. A relatively small sunshade could work, but it would have to be fairly close to Earth’s surface to block out the entire sun – and to stay that close, it would need to orbit at extraordinary speeds. The eclipse from such a small, fast-moving shade would only last a few seconds.
Instead, our hosts are taking on the challenge of parking something much larger in front of the sun to block it. A planet might work, but none in our solar system are quite the correct size – plus it would be difficult to move a whole world, and the consequences for Earth might be dire. In fact, changing how much sunlight reaches the ground at all could be a problem…
The solution may be a series of small panels, blasted into space individually and flown in formation to block the sun. There would need to be a whole lot of them, but changing their orientation in flight could provide solar eclipses on demand – without necessarily destroying all life on Earth.
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A single meteorite smashed into Mars and created 2 billion craters
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The Martian surface is heavily cratered
Stocktrek Images, Inc. / Alamy
When a single small meteorite struck Mars a few million years ago, it didn’t just create one crater. It ultimately created billions of them. The main crater, called Corinto, is just under 14 kilometres across, but the debris from that meteorite collision formed about two billion additional craters, called secondaries.
When a meteorite slams into the ground, it can blast a huge plume of rocks into the air. When these rocks fall back down, they create their own smaller craters, often in chains and…
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Europa’s seafloor may be impenetrable and inhospitable to life
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Europa has an underground ocean, but it might not be as hospitable for life as Earth’s seas are
NASA/JPL-Caltech/SETI Institute
Jupiter’s icy moon Europa may not be as ripe for life as previously thought. Its underground ocean has long made it one of the most promising candidates in our solar system to host life, but theoretical studies of its seafloor are putting a damper on its promise.
On Earth, much of the life in the oceans is supported by hydrothermal activity at the seafloor, where water interacts with rock. This activity…
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The moons of Mars may have been formed in an icy planetary collision
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How did Mars acquire its moons?
NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M University
The mystery of where Mars’s two moons came from may finally be solved. If Phobos and Deimos were formed when an icy object smashed into Mars, it could explain their contradictory properties, which have long baffled researchers.
Measurements of the geological makeup of Phobos and Deimos, including tentative signs of water, have suggested that they are more similar to asteroids than to Mars itself, hinting that they may be captured asteroids. However, that explanation would not account for their circular orbits, which instead hint…
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Bennu: How our golden age of asteroid exploration could reveal life’s origins
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ON THE morning of 24 September 2023, Dante Lauretta woke up early, his pulse racing. For 20 years, he had been working on a NASA space mission that aimed to scoop up a sample of an asteroid and return it to Earth. Now, it was time for the sample capsule to land. If anything went wrong, it could end up smashed to smithereens on the desert floor, as flat – and as useless to science – as a pancake.
Thankfully, the landing was successful. And since that day, researchers led by Lauretta, a planetary scientist at the University of Arizona, have been busily examining crumbly, jet-black material from the asteroid Bennu. Their mission, called OSIRIS-REx, is one of several similar efforts in what arguably adds up to a golden age of asteroid science. We now have no less than three pristine samples brought back from asteroids and there are thrilling plans afoot to visit others (see “Encounters with asteroids”, below).
Lauretta has written a book about the OSIRIS-REx mission called The Asteroid Hunter. Here, he tells New Scientist about why asteroid samples are important, what his team has discovered so far and his jaw-dropping hypothesis that Bennu might be a fragment of a lost ocean world, one which may have had warm, watery conditions that could have made it an incubator for the building blocks of life.
Joshua Howgego: You watched from a helicopter as the OSIRIS-REx samples landed. How tense was it?
Dante Lauretta: I got up at 1.30 that morning because we had…
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Tiny new moons have been spotted orbiting Neptune and Uranus
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The planets Uranus (left) and Neptune (right) have a few additional moons
NASA, ESA, Mark Showalter (SETI Institute), Amy Simon (NASA-GSFC), Andrew I. Hsu, Michael H. Wong (UC Berkeley)
Astronomers have spotted new moons around Uranus and Neptune for the first time in a decade. These are the faintest moons ever spotted orbiting any planet, and they prove a long-standing idea about satellites in the outer solar system.
Scott Sheppard at the Carnegie Institution for Science in Washington DC and his colleagues found these moons using the Magellan telescope in Chile and confirmed them using several other large telescopes around the world. “We looked about four times deeper than anyone has before,” says Sheppard. “These moons are on the edge of our ability – they’re just faint, faint points of light.”
Generally, when looking for moons, you can only take a picture with a maximum exposure of about 5 minutes before the image becomes overexposed and the movement of the moons makes it useless. Sheppard and his team got around this by taking many of these 5-minute images in a row, observing for hours and then combining the dim parts of the images. That enabled them to spot the dim points of light shining from the faintest moons ever discovered – and the smallest moons found to date around their respective planets.
The new moon around Uranus is provisionally named S/2023 U1, but it will eventually be given the name of a character in a Shakespeare play, to match the planet’s other moons. It is only about 8 kilometres across, and it completes an orbit once every 680 Earth days.
One of the new moons around Neptune is called S/2021 N1, and it awaits an official name from Greek mythology. It is about 14 kilometres across and takes about 27 Earth years to orbit the planet, making it the most distant moon from its host planet ever found. It is also the faintest moon ever found.
The discovery image of the new Uranian moon S/2023 U1, with scattered light from Uranus and trails from background stars
Scott S. Sheppard/Carnegie Institution for Science
The brighter, larger moon found orbiting Neptune is called S/2002 N5 – as its name suggests, it was first spotted more than 20 years ago, but it was lost before astronomers could confirm its orbit. “You can lose a moon really easily,” says Sheppard. “We basically need really, really good weather, we need the telescope to be working perfectly, we need everything to go right to detect these moons.” If anything goes wrong and a night of planned observations is lost, moons move in their orbits and become extremely difficult to find again, as happened with S/2002 N5.
Each of the three new moons has a similar orbit to two other satellites in its planetary system, and these fellow travellers form small groups that orbit together. This means that each of these groups probably formed together when a larger moon broke up in the chaos of the early solar system.
“Until now it was unclear whether Uranus and Neptune had these groups of outer moons like Jupiter and Saturn do,” says Sheppard. “We believe these are fragments of once bigger moons, and there are probably many more smaller ones to find.” Unfortunately, we are at the limits of what we can discover with current technology, he says, so it might be another long wait before any smaller moons than these are spotted around Uranus and Neptune.
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Carbon dioxide gas spotted in atmosphere of Jupiter’s moon Callisto
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The surface of Jupiter’s moon Callisto is scarred with impact craters, and its atmosphere holds carbon dioxide gas
NASA/JPL/DLR
Astronomers have spotted gaseous carbon dioxide across the atmosphere of Jupiter’s second-largest moon, Callisto, hinting that it might have a much more complex carbon cycle than we thought. On Earth, the carbon cycle helps to sustain a stable climate.
Callisto is one of the solar system’s oldest objects, having formed some 4.5 billion years ago around Jupiter. It is also one of the most battered objects, with a surface blanketed by craters.…
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Asteroid sampled by NASA may once have been part of an ocean world
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A sample from the asteroid Bennu, brought back by the OSIRIS-REx mission, feature hints that it was once part of a planetesimal with conditions favourable for life to emerge
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Strange alien worlds suggest Earth could survive the death of the sun
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MARK GARLICK/SCIENCE PHOTO LIBRARY
IT ALL seemed so simple when we knew the date of Earth’s demise. In 5 billion years from now, so the story went, the solar system will have dramatically transformed. Instead of being the benign presence we are used to, the sun will have ballooned into a giant, hundreds of times bigger than it is today. In the process, it will wipe out the rocky, inner planets, including our own.
Or will it? We have recently caught sight of the dying stages of other stars for the first time. And, miraculously, some planets seem to be able to survive these apocalyptic periods. Such observations are challenging the story of how Earth will die and giving us hope that it might somehow outlast the sun. Even if it doesn’t, all is not lost. The research is also giving us clues to where humanity could best take refuge.
How will the sun die?
The sun is powered by nuclear fusion, in which hydrogen atoms are melded together into helium, releasing vast amounts of energy in the process. But our star’s fate is sealed by one fact: it has a finite supply of hydrogen. As this begins to run out – in about another 5 billion years – the sun’s internal structure will change and it will expand to around 200 times its present size. It will transform from the yellow dwarf it is today into a red giant. After a further billion years or so, and another round of shrinking and ballooning, it will then die and shrink back down into a stellar corpse called a white dwarf.
As it grows to become a…
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