Jupiter was once twice as large as it is today
To better understand Jupiter's primordial stages, researchers turned to the tiniest of the planet's 92 known moons. Almathea and Thebe respectively circle Jupiter at slightly tilted orbits roughly 112,400 and 138,000 miles above the planet's cloudtops.
By analyzing the dynamics of these orbital discrepancies along with the planet's conservation of angular momentum, the team could estimate its radius and interior state at about 3.8 million years after the solar system formed its first solids. At that time, the sun was surrounded by a disk of material known as a protoplanetary nebula that was gradually dissipating as it coalesced into the planets we know and love. Based on their calculations, researchers believe early Jupiter was 2 to 2.5 times larger than it is today with a much more powerful magnetic field.
'It's astonishing that even after 4.5 billion years, enough clues remain to let us reconstruct Jupiter's physical state at the dawn of its existence,' said Fred Adams, one of the study's co-authors and a University of Michigan professor of physics and astronomy.
By focusing on the directly measurable information from Jupiter's moons and the conservation of its angular momentum, the team was able to sidestep many of the common uncertainties that plague planetary formation models. These often require astronomers to make assumptions about variables like gas opacity, accretion rate, and heavy element core mass.
According to the team, their new calculations enhance more than experts' understanding of Jupiter. These factors can be applied to the evolution of other giant planets as they circle stars. They also suggest that gas giants generally form through core accretion–or when a gas rapidly gathers around a core of ice and rock.
'Our ultimate goal is to understand where we come from, and pinning down the early phases of planet formation is essential to solving the puzzle,' said Konstantin Batygin, a Caltech planetary science professor and study co-author. 'This brings us closer to understanding how not only Jupiter but the entire solar system took shape.'
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Atlantic
a day ago
- Atlantic
Photos: 13 Years on Mars
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JPL-Caltech / MSSS / NASA This image looking toward the higher regions of Mount Sharp was taken on September 9, 2015, by NASA's Curiosity rover. In the foreground, about two miles from the rover, is a long ridge teeming with hematite, an iron oxide. Just beyond is an undulating plane rich in clay minerals, and just beyond that are a multitude of rounded buttes, all high in sulfate minerals. The colors are adjusted so that rocks look approximately as they would if they were on Earth, to help geologists interpret them. This "white balancing" to adjust for the lighting on Mars overly compensates for the absence of blue on Mars, making the sky appear light blue and sometimes giving dark, black rocks a blue cast. Curiosity photographed this feather-shaped iridescent cloud just after sunset on January 27, 2023. Studying the colors in iridescent clouds tells scientists something about particle size within the clouds and how they grow over time. 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New York Times
a day ago
- New York Times
Fly Fans Won't Keep Bugs From Crashing Your Barbecue. But Here's What You Can Do.
If these fans do work, the radius for efficacy is extremely limited. While dining outdoors with a Fly Fan, my colleague Rose Maura Lorre saw a fly land on the corner of a pack of hot dog buns. She got out a tape measure and found that the distance between the outer edge of the fan's blades and the fly's location was about 8 or 9 inches. Rose Maura Lorre/NYT Wirecutter Wirecutter bought a set of four fans for $49.99, a not-insignificant amount of money. I used the fly fans during some lake-adjacent dining with my colleague Rose Maura Lorre, and then I left two fans with her to continue testing. We found that even though the area directly under the fan's blades might be fly-free, you need to set up too many of them to make a difference across a table that seats six people. In fact, based on my experience, you'd probably want at least eight of these fans for a family of four. 'If I'm serving a family-style meal, the table top will already be crowded with plates, glasses and dishware,' Rose said. 'Adding three or four Fly Away fans to that clutter, with everyone passing dishes or reaching for condiments, I just think it could turn comical really fast.' Rose went so far as to measure the distance between the edge of the fan blade and the spot where she saw an offending critter alight on her table; it was about 8.5 inches. These fans have several positive aspects: They're quiet and portable, and they don't use chemical pest control. But all two of the bug researchers I contacted were dubious about the efficacy of fly fans. The theory is that a fly fan disrupts the visual and olfactory senses of flies, and that prevents them from wanting to land on the delicious-smelling food. But this may be only a temporary blocker, Michael 'Fly Man' Dickinson, who researches how flies fly at CalTech, said in a video interview. The air movement generated by the fly fan isn't fast enough to throw them off-course. 'Flies are attracted to food,' Changlu Wang, whose research at Rutgers University focuses on developing urban pest-management technologies, explained in an email. 'It is hard to prevent them [from] coming when you have attractive food around.' Even if the flies are initially deterred, their motivation to access the yummies is likely stronger than the spinning obstacle. And when flies do manage to land on your burger, the slowly circulating blades may actually stop them from taking off again. 'Flies can only fly so fast, so if they know there's going to be headwinds that they can't deal with, they won't take off,' Dickinson explained. The experts I consulted aren't aware of a peer-reviewed scientific study that verifies a fly fan's efficacy, and my observed results were anecdotal.
Tom's Guide
4 days ago
- Tom's Guide
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Like it or not, routine is what your body needs to get a good night's sleep night after night. Yet, understandably, as your social life and academic pressures ramp up at college, bedtimes and wake-up times can go a little haywire. I've always been aware of the link between sleep and learning. So sleep was something I prioritized (as best as I could) at college. After recently graduating, I can honestly say maintaining a consistent sleep schedule was the one habit that made sure I rested well and bagged good grades, all while juggling a social life too. So, how can you make sure you're keeping it on track as best as you can? With a reliable sleep tracker. Of course, there are plenty of products you can shop in back to school sleep sales, from the best cheap dorm mattresses to cosy bedding. But if you're looking for a gadget to hold yourself accountable around going to bed and waking up at the same time each day, a sleep tracker should be on your shopping list. Yes, top of the range sleep trackers can be pricey gadgets. But I've shopped around to find you the best budget options available right now. Science shows a link between sleep regularity (i.e. going to sleep and waking up at the same time each day), improved brain function and better wellbeing among college students. Research by associate professor of neurology at the University of Michigan, Dr. Shelley Hershner, specifically found students with greater sleep consistency have better academic performance. Get instant access to breaking news, the hottest reviews, great deals and helpful tips. Meanwhile, a 2019 study published in the Sleep Research Society journal agrees that stabilizing sleep schedules can help improve well-being among students. This is because a consistent sleep schedule helps to regulate your circadian rhythm, so your body gets used to releasing sleepy hormones like melatonin at the right times of day. In turn, it's easier to fall asleep fast at night, bag quality sleep and wake up with energy for class in the morning. So, you know going to sleep on time will help your studies and overall health. But without your mom there to tell you it's time for lights out, strict bedtimes can easily become a thing of the past. This is where a sleep tracker can come in handy at college. I tracked my sleep with my Garmin watch through college and have recently experimented with a wider range of trackers including Oura, Whoop and Eight Sleep in my role as a sleep tech tester. While they all vary in the detail they go in to, even the most basic sleep tracker will deliver two key metrics — the time you fall asleep and the time you wake up. These alone can help you cement the healthy sleep habit of going to bed and waking on time. Trust me, notifications from your friendly sleep tracker telling you it's time to sleep somehow guilt trip you into halting the doom scroll and hitting the hay on time. With a student budget in mind, these are the top 5 sleep trackers I recommend shopping before the semester starts... 1. Fitbit Inspire 3: was $99.95 now $79.95 at WalmartThe Fitbit Inspire 3 is a top-rated, affordable health tracker that does a grand job of tracking basic sleep metrics like sleep timing and duration. Though you can get more in-depth sleep tracking from Fitbit if you're willing to get behind the Fitbit Premium paywall (it'll set you back $9.99/month). As a small smart watch, the Inspire 3 sits comfortably on your wrist overnight and packs 7+ days battery life. 2. Amazfit Heilo Strap: now $99.99 at AmazonFrom the Amazfit Active smart watch to the Amazfit Heilo ring, we're big fans of Amazfit health trackers here at Tom's Guide. The brand is known for producing affordable versions of industry-leading trackers and the Heilo Strap is essentially their take on the Whoop band. At $99.99 without a subscription fee, it is a great value health and recovery tracker that monitors heart rate, blood-oxygen, stress, and sleep. 3. Oura Ring 3: was from $299 now from $199 at OuraStylish and intricate when it comes to its sleep reports, the Oura Ring 3 is my favorite sleep tracker. Yet, requiring a subscription fee at $5.99 per month, it's the more premium option here - one for the students looking to seriously invest in their sleep health. That said, there's currently $100 off the Oura Ring 3 while stocks last. Plus, I've tested the Oura Ring 3 alongside the new and upgraded Oura Ring 4 and think you're getting better value for money with the previous generation — it's perfectly functional and studies show it is reliable too. 4. Milavan Smart Ring: was $59.99 now $49.99 at AmazonOf course, the Oura Ring is the gold-standard sleep tracking ring, but at $200+ and requiring a monthly subscription fee, it's not the most student budget-friendly. The Milavan is a more affordable alternative that monitors your sleep quality and recommends habits for improving your sleep health. It's rated an average of 4.4 out of 5 stars by Amazon customers who say it's "surprisingly smart". With $10 off now it's even more affordable. 5. Withings Sleep Analyzer: was $159.99 now $151.99 at AmazonIf you'd prefer to snooze wearable-free, an under mattress sleep tracker is a great option for you. The Withings sleep tracking pad slips under your mattress and keeps tabs on everything from your sleep stages to sleep duration and snoring. Our Certified Sleep Science Coach and Senior Sleep Editor Claire Davies says Withings is about as close to an at-home polysomnography test as you can get - pretty cool, huh? With 5% off at Amazon now you can get it for the slightly cheaper price of $151.99 (down from $159.99). It's another more expensive option, but a worthy investment in your sleep health and overall wellbeing.
