Latest news with #Saturn-like
Scientific American
22-05-2025
- Science
- Scientific American
How One Astronomer Helped to Discover Nearly 200 Moons of Saturn
A mere decade ago, astronomers knew of just 62 moons around Saturn. Today the ringed planet boasts a staggering 274 official satellites. That's more than any other world in the solar system—and far too many for most people to keep track of. Astronomer Edward Ashton is no exception, even though he has helped to discover 192 of them—he thinks that's the total, anyway, after pausing to do some mental math. Ashton is now a postdoctoral fellow at the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan. He fell into hunting for Saturn's moons in 2018, when his then academic adviser suggested the project for his Ph.D. at the University of British Columbia. It has been a fruitful search. Most recently, in March, Ashton and his colleagues announced a batch of 128 newfound Saturnian satellites. Scientific American spoke with Ashton about the science of discovering so many relatively tiny moons—most of them just a few kilometers wide—using vast amounts of data gathered by the Canada-France-Hawaii Telescope (CFHT), located in Hawaii. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. [ An edited transcript of the interview follows.] How have you found these moons? To detect the moons, we use a technique known as shifting and stacking. We take 44 sequential images of the same patch of sky over a three-hour period because, in that time frame, the moons move relative to the stars at a rate similar to Saturn. If we just stack the images normally, then the moon appears as a streak across the images, and that dilutes the signal of the moon. So what we do is: we shift the images relative to one another at multiple different rates near that of Saturn, and then we basically blink between the different shift rates. If the shift rate is not quite at the rate of the moon, then it's going to be slightly elongated. As you get closer to the rate of the moon, then it slowly combines into a dot. And then, as you get faster than the moon's rate, it expands again. So basically, we look at the images and then quickly blink through the different rates, and you can see the moon coalescing. That's for a single night. But just seeing an object moving at a Saturn-like rate near Saturn doesn't guarantee that it is a moon. It's highly likely that the object is a moon, but that hasn't been confirmed. So what we need to do is track the objects to show that they are in orbit around the planet. To do that, we repeat the [shift and stack] process multiple times over many months and years. Why did this happen now? Did you need new techniques and observatories to do this work? The technique and the technology have been there for a while—the same technique has been used to find moons of Neptune and Uranus. But the sky area around those planets where moons can exist is a lot smaller, so it takes less time to search through the data. One of the reasons why this hadn't been done for Saturn is because it's very time-consuming. Why do those other planets have less space where moons could be than Saturn does? Those planets are less massive, so the stable orbits that moons can have are smaller. I had been wondering if this technique works for other planets, and clearly the answer is yes. But do you think there are other moons that have yet to be found around Saturn or other planets with the method? We did find moon candidates around Saturn that we weren't able to track long enough to be able to confirm them. So if you redo this technique again, you will be able to find more moons around Saturn, but this is a case of diminishing returns. If you use a larger telescope [than the CFHT], then you'd be able to see fainter moons, so you'd be able to find more. At the moment, if you use the same technique for Jupiter, you will be able to find fainter moons. The problem is: the amount of sky that moons of Jupiter can occupy is significantly larger than [the amount of sky that can be occupied by moons of] Saturn, so the method is even more time-consuming for Jupiter. And Jupiter is much brighter than Saturn and the other planets, so there's a lot of scattered light that makes it harder to see the moons. So it's even harder to find satellites around Jupiter, and as you mentioned, other groups have already done this work for Uranus and Neptune. Does that mean we're sort of 'maxed out' on moons until we have better observations? Yeah, you probably have to wait until better technology comes along. Is there something being built or planned right now that could be that 'better technology'? There currently are telescopes that can see deeper [than the CFHT], such as the James Webb Space Telescope (JWST). The problem is: JWST's field of view is very small, so you have to do quite a few observations to be able to cover the required area. But there is a telescope that's set to launch pretty soon, the Nancy Grace Roman Space Telescope, that has quite a large field of view. So that'll be a good telescope to use for hunting more moons. What do we know about these new moons? You basically can only get the moons' orbits and approximate sizes. But if you look at the distribution of the orbits, you can understand a bit more about the history of the system. Moons that are sort of clumped together in orbital space are most likely the result of a collision, so you can see what moons come from the same parent object. Is seeing so many moons around Saturn unusual? What's unusual is how many there are. It appears that the planets have more or less equal numbers of the larger moons. But when you get down to the smaller ones that we're discovering, Saturn seems to shoot up in terms of the numbers. So that's quite interesting. This could just be because there was a recent collision within the Saturnian system that produced a large number of fragments. Do you get to name them all? Do you have to name them all? I guess I don't have to. Some of these new moons, they've been linked back to observations by a different group from more than 10 years ago. That's maybe 20 to 30 of them. For the rest, we get full discovery credit, which, I think, means we get the right to name them. But they can't be named just yet; first, they're just given a number when they have a high-precision orbit, and I'm not sure how long that's going to take. Do you have more moon-hunting observations to analyze? No, I'm taking a little break from moons! I've got other projects to work on, relating to trans-Neptunian objects. They're quite far away. They're hard to see. There are some mysteries about them at the moment. It's interesting to understand their structure and how it relates to planet formation.
Yahoo
25-04-2025
- Science
- Yahoo
The sun might be making water on the moon, NASA study finds
When you buy through links on our articles, Future and its syndication partners may earn a commission. Constant gusts of particles from the sun may be creating water molecules on the moon, a new NASA-led experiment hints. Scientists have detected traces of water molecules — as well as hydroxyl (OH) molecules, a component of water — on the surface of the moon through multiple space missions. The source of this water has long been a mystery, though some theories suggest volcanism, outgassing from deeper in the lunar regolith (the combination of rock and dust on the surface of the moon), and bombardment by tiny meteorites. The new NASA experiment, described March 17 in the journal JGR Planets, tests a different idea: that solar wind is behind it all. Solar wind is a constant gale of charged particles streaming from the sun at over 1 million mph (1.6 km/h). It bombards everything in the solar system, including Earth, and causes colorful auroras when it collides with molecules in our atmosphere. Our planet's magnetosphere shields us from the brunt of this space weather. The moon, however, has a very weak and splotchy magnetic field, so it is less protected. Water is made up of hydrogen and oxygen atoms. The rocks and dust making up the surface of the moon contain a lot of oxygen but not a lot of hydrogen. Solar wind is mostly made of protons, which are hydrogen atoms missing their electrons. Without a strong magnetic field to protect it, the solar wind slams into the moon's surface every day, seeding it with protons that steal or borrow electrons from the lunar regolith to form the hydrogen needed to make water. Related: Earth's moon could've had Saturn-like rings, new study hints According to NASA, the water that's been detected on the moon follows an interesting pattern — it changes on a daily cycle. Areas warmed by the sun release water as vapor, while colder regions hold onto it. If the source of water was something like micrometeorite collisions, we might expect the water to keep decreasing in warm areas until more impacts occur. However, the amounts of water detected return to the same levels every day, even as some of it is lost to space. This makes it more likely that solar wind is involved. To test this theory, the researchers simulated the effects of solar wind striking the moon using samples of lunar regolith collected by Apollo 17 astronauts in 1972. They built a tiny particle accelerator in a vacuum to launch "mock solar wind" at the samples for multiple days, simulating the effects of the real solar wind hitting the moon for 80,000 years. Then, they measured how the chemical makeup of the sample had changed — and it showed evidence of water that wasn't there before. RELATED STORIES —NASA rover discovers out-of-place 'Skull' on Mars, and scientists are baffled —15 incredible images of Earth's moon —1st mission to 'touch' the sun discovers a mysterious source of solar wind "The exciting thing here is that with only lunar soil and a basic ingredient from the Sun, which is always spitting out hydrogen, there's a possibility of creating water," study lead author Li Hsia Yeo, a planetary scientist at NASA's Goddard Space Flight Center, said in a statement. Understanding how water forms on the moon is important for future astronaut missions, the researchers said. Water ice stored at the lunar south pole could be an important resource for astronauts, for example. The results also provide insight into the solar wind's interactions beyond the moon. Other celestial bodies that don't have much of an atmosphere or a magnetic field are also bombarded by solar wind, so studying how these environments change can help us understand celestial chemical processes that generate or strip away water, a key building block for life.
Yahoo
26-03-2025
- Science
- Yahoo
Saturn's Pulling a Stunt That Hasn't Happened Since 2009: How to Watch
It's not every day that a prominent feature of our solar system disappears, but that's precisely what will happen with Saturn. Over the weekend, Saturn's gorgeous rings will nearly vanish from sight. No worries, they'll be back in a couple of weeks. This phenomenon is caused by an optical illusion that occurs when the stars line up. Saturn is tilted at 26.73 degrees on its orbit, while Earth is very close to that at a 23.5-degree tilt. When the two planets line up just right, the rings of Saturn are almost entirely horizontal from the perspective of Earth, causing them to mostly vanish. Read more: Best camera to buy in 2025 So, anyone looking up at the sky this weekend will likely note that the planet won't look very Saturn-like without its trademark rings. However, if you're using a powerful telescope, the rings will still be visible. It'll appear as though a thin line is running through the middle of Saturn, as shown in the graphic above. The tilt of Saturn and Earth is the main thing. It's like looking at a piece of paper. If you hold it horizontally up to eye level, it'll be practically invisible. Paper is an apt analogy here because Saturn's rings are very thin. According to NASA, Saturn's rings average about 30 feet in height across the entire length of the ring. That means when viewed from the side at a distance of about 1.5 million kilometers (983,000 miles), you might as well be looking at a sheet of paper from the side. The rings are still technically visible. Folks with higher-powered telescopes may be able to see the line jutting across Saturn. However, those with low-power telescopes may not see it, making Saturn look naked. The peak of this little celestial dance will occur over the weekend. So, technically, the rings have already been like this for a week or two and will continue to be difficult to see going into April. By then, Saturn's orbit will begin to tilt the rings again, and they will slowly come back into view over the next month or two. According to NASA, this happens about every 13 to 15 years on average. It's not an exact science, though, as prior events occurred in 1980, 1995 and 2009. The next one is predicted to come in 2038 or 2039.
