Humanity Just Moved an Asteroid's Orbit Around the Sun

You're listening to Astronomy Daily. I'm Anna and I'm Avery. It is Saturday, the seventh of March twenty twenty six, and as usual, we have a packed show for you today. We absolutely do. Here's a question to get you thinking. Back in September twenty twenty two, NASA slammed a spacecraft into an asteroid. You probably remember that, but did you know that we only just confirmed something remarkable. That impact didn't just nudge the asteroid, It actually changed the orbit of an entire asteroid system around the Sun. For the first time in human history, we move the celestial body's solar orbit. And that's just story one. We've also got gravitational waves, a spacecraft emergency, an orbit, a forty five year old theory biting the dust, our young Sun blowing its very first cosmic bubble, and the gorgeous double planet show. Intonight, sky, let's go. So let's kick off with the dark story, and I think it deserves a moment to really sync in. We already knew that Dart was a success. We knew it shortened the orbit of dimorphous around its partner asteroid Ditamos by about thirty three minutes. That was confirmed back in twenty twenty two, but a new study published yesterday in the journal Science Advances has revealed something even bigger. Right, because ditamos and dimorphous are gravitationally linked, they moved together, and researchers have now confirmed that the debris blasted off Dimorphous during that impact was so enormous We're talking over a million kilograms of rock and dust, that it gave the whole binary system an extra kick. And that extra kick was measurable. The orbital period of the entire Ditamo system around the Sun shortened by zero point one point five seconds. Now, I know that sounds tiny, but this is the first time a human made object has measurably changed the path of a celestial body around our star. To even measure that, the team had to get incredibly creative. They tracked what are called stellar occultations, moments when the asteroid passes in front of a background star and briefly blocks its light. Volunteers around the world contributed twenty two of these observations between October twenty twenty two and March twenty twenty five. Twenty two pinpoint moments of a star blinking out and from those They derived the change of zero point fifteen seconds in a seven hundred seventy day solar orbit. The momentum enhancement factor turned out to be about two, meaning the debris ejected by the impact roughly doubled the total push given to the asteroid. Dart didn't just hit dimorphos, it turned a dimorphous into a rocket, and. Thomas Statler, leads Sciences for Solar System Small Bodies at NASA Headquarters, framed it perfectly. He said, a tiny change can, and given enough time, grow into a significant deflection. This result validates kinetic impact as a genuine planetary defense technique, not just for nudging a moon, but for altering the path of an entire binary system around the Sun. Lisas harrispacecraft, which launched in twenty twenty four, is expected to arrive at the Ditamo system later this year to study the aftermath of close, though the science from this impact is very much still unfolding. Story two and it is a landmark one. The LGO Virgocagra collaboration the LVK has just published the fourth edition of the Gravitational Wave Transient Catalog known as GWTC four, and the headline they've more than doubled the total number of gravitational wave detections ever made. Before this release, the entire catalog contained ninety candidates from three previous observing runs stretching back to twenty fifteen. New catalog adds one hundred and twenty eight new events, all detected during just the first nine months of the fourth observing run between May twenty twenty three and January twenty twenty four. So we've gone from ninety to two hundred and eighteen in one update. And it's not just the quantity that's exciting, it's the variety. The catalog includes the heaviest black hole binary merger ever detected, with each black hole weighing in at around one hundred and thirty times the mass of our Sun. There's also a binary where both black holes are spinning at roughly forty percent the speed of light, and there are two new mixed mergers, a black hole colliding with a neutron star. Each one of those is a treasure trove for astrophysics. Daniel Williams, a researcher at the University of Glasgow and LVK member, put it well. He said they're pushing into new parts of parameter space, seeing things that are more massive, spinning faster, and more astrophysically unusual than anything detect before. What I love about this is what it means for testing Einstein. The catalog includes an event with one of the loudest gravitational wave signals ever recorded GW two three zero eight one four, and the team used it to run precision tests of general relativity. It passed with flying colors, but the fact that we're now running those tests on events this extreme is remarkable. Bigro and its partners are currently in a maintenance break, but a new six month observing run is expected to begin in late twenty twenty six. Given how rapidly the catalog is growing, that run could double it again. All right, story three, and this one has a genuine element of suspense. Europe's Proba three mission is in trouble. Issa confirmed yesterday that they have lost contact with one of the two spacecraft that make up the Proba three mission. Let me explain what Proba three actually is, because it's a fascinating concept. It launched from India back in December twenty two, twenty four, and it consists of two separate spacecraft designed to fly in extraordinarily precise formation about one hundred and fifty meters apart. To create artificial solar eclipses in space. One spacecraft, the occult, physically blocks the bright face of the Sun. The other, the coronagraph, uses that shadow to image the Sun's faint outer atmosphere, the corona, without being blinded by the solar disc. And to make this work, the two spacecraft must maintain alignment to within millimeter accuracy. It's an almost absurdly precise operation, and it was working. In May of last year. The spacecraft achieved their landmark formation flying test. In June, they captured the first ever images of an artificial solar eclipse in space. It was a genuine technological first. And then on the weekend of February fourteenth, something went wrong. The CORONAFT spacecraft, the one doing the imaging experience hinst an anomaly that prevented it from entering safe mode. Issa describes it as a progressive loss of attitude. In other words, the spacecraft slowly lost its orientation. As it drifted. Its solar panels moved away from the Sun, the batteries drained, the spacecraft dropped into survival mode and contact was lost. ESA says root cause is under investigation, and they're exploring whether the companion occult or spacecraft can be maneuvered closer to assist in recovery. Losing either spacecraft would effectively end the probe of three mission. ESA says teams are working hard and they will provide updates as new information becomes available. This is very much a developing story. We'll keep following it. Story four is a classic example of a long held scientific belief getting overturned. For forty five years, astronomers thought they understood how stars like our Sun change as they age, specifically how their rotation pattern evolved. The idea this our Sun rotates differentially. The equator takes about twenty five days to complete one full rotation, while the poles take about thirty five days. Equator faster, poles slower. That's called solar type differential rotation, and scientists believed that as stars slowed down over billions of years, they would eventually flip the poles would start spinning faster than the equator instead. That flip state was called antisolar differential rotation. Theoretical simulations predicted it. No one had ever observed it, but the model said it should happen, and for decades the lack of observations was attributed to limitations in our telescope technology. But now researchers at Nagoya University in Japan have used Fugaku, the country's most powerful supercomputer, to run the most detailed simulations ever of stellar interiors, and the result is clear. The flip doesn't happen. Key was resolution. Previous simulations were low resolution, and magnetic fields faded out of the models entirely. At high resolution, we're talking five point four billion grid points per simulated star, the magnetic field stayed strong, and those magnetic fields, it turns out, are what prevent the rotation from flipping. Professor Heidiyuki Haata, one of the co authors, set it simply, turbulence and magnetism keep the equator spinning faster than the poles throughout the star's life. The switch doesn't happen because magnetic fields, which previous simulations missed, prevent it. And there's a bonus finding magnetic fields in solar type stars weaken continuously throughout their lifetime with no revival In old age, previous models had predicted a magnetic comeback that doesn't happen either. This matters practically too. A corrected model of stellar rotation helps us better understand the Sun's eleven year sunspot cycle and could improve our predictions of how magnetic activity affects the habitability of planets orbiting Sun like stars over billions of years. Dory five and it's a lovely one. A real window into our own Sun's distant past. NASA's Chandra X ray observatory has captured the very first image of what's called an astrosphere around the sun like star. Our Sun has a protective bubble around it, called the heliosphere, created by the solar wind streaming outward and carving out a cavity in interstellar space. It's enormous. It extends far beyond the outer planets and shields the Solar System from harmful galactic cosmic rays, but we've never been able to photograph it from the outside. The star Chandra observed is called HD sixty one zero zero five, and it sits about one hundred and twenty light years away in the constellation Pupis. It has roughly the same mass and temperature as our Sun, but it's only about one hundred million years old. Our Sun is around five billion years old, so HD six one zero zero five is cosmically speaking a baby, and because. It's so young, its stellar wind is dramatically more powerful. It blows about three times faster, and it's twenty five times denser than the wind from our Sun today. That's why its astrosphere is bright enough to detect an X rays. The powerful wind collides with the surrounding interstellar dust and gas, and that collision produces X ray emission that Chandra can detect. The astrosphere has a diameter roughly two hundred times the distance between Earth and the Sun. Carry Lists of Johns Hopkins University, who led the study, put it beautifully, We've been studying our Son's heliosphere for decades, but we can never see it from the outside. This is the closest thing we have to a photograph of what our own Sun's bubble look like several billion years ago. The star is also nicknamed the Moth because a surrounding disc of dust forms a mothlike structure around it, and interestingly, the dense dusty environment is actually part of why the astrosphere is so visible here, making HD six one zero zero five a uniquely ideal subject for this kind of observation. And we'll finish with some skywatching news because tonight and tomorrow night offer something quite special. Venus and Saturn are meeting up in the evening sky, and it's a treat for anyone who can get outside shortly after sunset. Venus is already impossible to miss right now. It's shining at magnitude minus three point nine, which makes it by far the brightest object in the sky after the Sun and moon. Tonight and tomorrow, Saturn sits close alongside it, though considerably fainter at magnitude one point zero. The best time to look is about thirty minutes after sunset, when Venus will be roughly seven degrees above the western horizon. Binoculars will help a lot. Saturn should pop into view easily near brilliant Venus. You'll have about seventy minutes before both planets set, and. If you're pointing a telescope at Venus tonight, you're in for an extra treat. The planet is currently showing a ninety seven percent lit disc, almost fully illuminated from our perspective. It's a gorgeous site. Neptune is also lurking nearby, just over a degree from Saturn, though you'll need a telescope to catch that one. So get outside this evening. If skies are clear, Venus is your guide. Find that brilliant white beacon low in the west, and Saturn will be right there waiting for you. And that's our show for today. Six stories from an asteroid nudged around the Sun to a planet pairing up Intonight's sky. It's a great time to be paying attention to the universe. If you enjoyed today's episode, please subscribe wherever you're listening and leave us a rating or review. It genuinely helps a show reach more people. You can find us at Astronomy Daily dot io for the blog and show notes, and follow us at astro Daily Pod on all the major social platforms. Until Monday, keep looking up clear skies, everyone. Sunday Starsz Starz