On October 19th, 2017 we learned about

Frozen pee may be a practical reference point in our future search for life on Enceladus

In 2005, the Cassini spacecraft captured images of plumes of icy water erupting from Saturn’s moon, Enceladus. Subsequent flybys and sampling have suggested that this moon may be habitable by some form of life in its sub-surface ocean, thanks to geological heating. However, this is all inconclusive at this point, because Cassini wasn’t designed to tackle this kind of mission. Even when the spacecraft was flown through the moon’s icy geysers, it could only sample a limited portion of the ejected slush, since the probe could only detect one size of ice grain at a time. Now that Cassini has been crashed into Saturn, researchers are hoping to get another probe to Enceladus, but they need to make sure it’s ready for the job, and that means developing a better understanding of frozen water when it’s flushed into space.

In better tailor sensors for the icy ejecta of Enceladus, engineers would like experiment with, or at least observe, water as it flows into the cold vacuum of space. Of course, water is heavy and therefore expensive to get off the ground, plus astronauts value it as a way to stay, you know, alive. So rather than fly water up to space only to toss it out, it’s been proposed that we start paying closer attention to how wastewater from astronauts’ toilets as well as fuel cells, behaves when it’s vented from spaceships. Wastewater, or any water, spewed from a small metal tube wouldn’t be a perfect proxy for the vents of Enceladus, but it may be a starting point for measuring what kind if ice crystal distribution should be expected.

Previous work with purged pee

There’s also some precedent for these observations. In 1989, researchers used a telescope in Hawaii to watch as the space shuttle Discovery dumped water from its fuel cells. They couldn’t develop a full 3D model from these observations, but they could at least note that two sizes of ice grain formed. Bigger pieces of ice formed right out of the vent, while smaller grains, probably from recondensed water vapor, formed further away. The space shuttles also ejected liquid waste while on missions, although they made sure to keep the astronauts poop for later disposal back on Earth. Some of this vented liquid was found to form long icicles just outside the vents, suggesting another phenomenon that could be found on Enceladus.

While space shuttles dumped liquids more often, the International Space Station doesn’t quite provide the same opportunities to observe frozen pee. Pee isn’t sprayed into space as much anymore, partially due to the realization that frozen urine ejected from the Mir space station in the late 1980s had been slowly damaging the facility’s solar panels. Instead, most of the astronauts’ pee is cleaned and recycled into drinking water, leaving only the most concentrated, briny, urea to be purged into space. Astronauts’ poop doesn’t get tossed out either, but is instead packaged with other bundles of trash that are dropped into the natural incinerator that is the Earth’s atmosphere.

With these limitations, it’s not clear how much we’ll learn by watching astronaut’s waste water. At the very least, the stuff humans flush can at least provide a basic reference point for what to expect the next time we’re near Enceladus.

Source: Astronaut wee could show us how the plumes on Enceladus work by Leah Crane, New Scientist

On October 16th, 2017 we learned about

Gravitational waves help scientists spot the collision of two neutron stars

My daughter loves hearing about astronomy, as the movement of the planets, the unfathomable scale of the universe, and unanswerable questions like “is the universe contained in something?” really excite her imagination. So with today’s announcement that astronomers had finally observed the collision of two neutron stars, it seemed like the perfect story to share with her. If only we hadn’t gone out for candy-laden frozen yogurt an hour earlier…

Me: So once up on a time, two stars blew up.

Four-year-old: That’s bad.

Eight-year-old: It happens eventually to all stars, right?

Me: Well… many of them? The point is the stars were the right size to use up all their full, supernova and be left as neutron stars.

Eight-year-old: What’s a neutral star?

Me: “Neutron,” but that’s a good connection to make. A neutron star is the remains of a star that’s basically made of neutrons, which is a neutrally-charged part of an atom, as compared to positive protons and negative electrons. Anyway, the important thing here is that a neutron star is incredibly dense. You remember density?

Eight-year-old: That means it’s… hot?

Me: No, it’s not about how much energy it has, but how tightly packed together all of it’s material is. So in this case, imagine something that if you put it on Earth somehow would weigh more than our Sun, but was small enough to fit in a space between San Francisco and the San Francisco Airport.

Kids together: Whooooaa…

Me: Yeah, it’s so packed together that–

Eight-year-old: But is it hot?

Me: Well, it’s not inert. It has some some energy as we’ll see, but I’m not sure about its temperature. [Post-bedtime fact-check: Neutron stars are hotter than Earth, but cooler than most stars.]

So the mass of a neutron star is so dense that a teaspoon full of neutron star would weigh a billion tons. They’re a ton of stuff in a small amount of space. But all that ‘stuff’ means that they have a lot of gravity, which is imporant when these two stars started circling each other. As they drew closer, they started orbiting each other, but also tearing each other apart.

Kids: Oooo….

Me: As they spun closer and closer, their immense collective mass started emitting gravitational waves. Do you remember the last time we heard about those?

Eight-year-old, now hanging upside-down off the couch: Uh….

Me: We last heard about this when new sensors detected two black holes crashing into each other. The impact send out waves that were basically warping the universe just a tiny bit, and sensors at two seperate buildings were set to notice when lasers were stretched a tiny bit?

Eight-year-old: Oh right!

Me: Well, those two facilities were called LIGO [Laser Interferometer Gravitational-Wave Observatory], and now a third set of sensors has been set up in Italy, called VIRGO, which is doing the same job. To get back to our neutron stars, we know that 130 million years ago, the two stars finally collided, because the waves from their collision arrived at the Earth, and were picked up by these sensors, around two months ago.

Eight-year-old: Two months ago?!

Me: The collision was very far away- around 130 million light-years. The cool thing was that when the gravitational waves were detected, people were notified to jump into action and start looking for the light that they were expecting to follow.

This kind of collision had been predicted, and the size and shape of the gravitational waves looked like what people expected of crashing neutron stars. So they thought that, unlike a black hole, there’d be some light for telescopes to see. Lots of people at observatories around the world started scanning the sky to find traces of the exploding neutron stars, which is called a kilonova.

Four-year-old: What’s an observatory?

Me: A place with a high-powered telescope.

Eight-year-old: Does that mean it was in the sky the before? Did the constellation [Hydra] change?

Me: They did get to see it, but it wasn’t previously visible.

Many, many teams started working together to look for the colliding neutron stars. One guess is that 25 to 30 percent of all astronomers on Earth helped out with this to get as much information from different telescopes as possible. Finally, someone [Charlie Kilpatrick] from UC Santa Cruz, nearby, found a new bright spot near another star. He told everyone to “look over here!” and you could see a blip appear over time. First it was blue, then red, and then dimmed away to nothing.

It was emitting light, but also something called gamma radiation, which is just a form of energy. We can’t see it, and it usually just flys right through us without doing anything. A lot of it was released in the collision, which is what all the telescopes were really looking for.

We had talked about what it meant to be an “author” on a paper the other day, right? Well, one of the papers about this event has about 3,500 authors on it because so many people helped out.

Eight-year-old: You’re like an author, right Daddy?

Me: Well, not like that kind of author.

Eight-year-old: But you write about science stuff.

Me: But I’m not contributing to experiments or anthing. It’s different…anyway…

Eight-year-old mumbling something…

Me: Because there was so much mass and energy between the two stars, when they smashed together they could essentially make a lot of new atoms. Not making them out of nothing, but recombine material to make new atoms that don’t get created all that often. Most new atoms made by stars are light, like hydrogen, but in this case the neutron star was making heavy metals, meaning silver, gold, platinum, and…

Eight-year-old: Gold?! Oh! Money money money money money…

Me: Uh, yeah. They estimate that there was probably so much gold created in this collision you could ball it up into something the 10 times the size of Earth.

Both kids: Whoaaa….

Eight-year-old: You could be soooo rich!

Me: If you could do something with it, yeah. We use gold for lots of stuff, like some of Mommy’s jewelry, or inside electronics like cell phones, and–

Four-year-old: I want to see Mommy’s jewelry!

Eight-year-old, upside-down again: Inside phones?! Money money money money money…

Me: Ugh… right. So to have any of these metals on Earth means that before the Earth was formed, other neutron stars must have collided and released all these metals, some of which got bundled with the other rocks and dust that eventually clumped together to form the planet. We now dig these things out of the ground to use for all sorts of stuff, like earrings or even dipping strawberries

Eight-year-old: People do that? What?!

Me: Yeah, we put use gold for all kinds of things, but my point is that none of it was from Earth originally. It all came from these huge explosions in space!

Eight-year-old: …my friend said she bought gold for two dollars. Is that real?

Me, realizing I’ve totally lost my audience: If it was a small amount. Two-dollars worth of gold.

Eight-year-old: So it’s made up? The price?

Me: Prices are only what we decide… look, people predicted this is where these heavy metals came from, and now for the first time we’ve been able to observe that happening. We’ve never seen neutron stars colliding before! This work also helps us learn about the expansion rate of the universe, because we can now compare the speed of the gravitational waves to the speed of the gamma radiation. It’s also an amazing project to have so many people working as a team across the globe in a way that just wasn’t possible before!

Eight-year-old: …

Me: You know, platinum is worth more than gold per ounce?

Eight-year-old: Money money money money money…

Me: Bed time?

Source: In a First, Gravitational Waves Linked to Neutron Star Crash by Nadia Drake, National Geographic

On October 10th, 2017 we learned about

Baryons confirmed to constitute a considerable portion of the universes’ invisible material

We call it outer space, but that really paints the wrong picture of just how much stuff is really out there. Yes, the distances between objects are usually bigger than we can truly comprehend. Sure, there’s a lot of cosmic territory that look empty, neither reflecting or emitting any kind of detectable energy, from light to heat. However, the movement of the things we can see indicates that there’s a lot more matter in the universe, even it’s not directly visible. Researchers have long trusted that gravity hasn’t been fooling us, and now two teams have finally found some of that imperceptible stuff that scattered throughout space.

Deciphering the dark

When we look out at the universe with our eyes, telescopes, microwave detectors and more, we really only see about 20 percent of what we know must be out there. The 80 percent that we can’t directly observe is referred to as dark matter, since it never shows up as a source of light or other energy when we look. However, the behavior of planets and stars would only make sense if they were being influenced by the gravity of a lot unseen material. As confident as astrophysicists are about the gravitational forces that should be shaping the universe, it’s always good to try to validate one’s models, even if it’s just to confirm what was mostly already known.

Cranking up the contrast

In this case, two teams of researchers have independently imaged clouds of tiny particles called baryons. Baryons are smaller than a proton, consisting of only three quarks. That size reduces their chances of interacting with something like visible light, which is part of why we don’t see the huge swaths of them floating around space. To make things even trickier, they’re distributed in diffuse clouds between galaxies, making whatever traces they’d leave on their surroundings even harder to detect.

To make these baryon clouds more obvious, both teams used a technique which essentially upped the contrast on our readings of two galaxies that had been observed by the Planck satellite in 2015. Both groups overlaid the observed data on itself over a quarter-million times, making the clustered baryons more obvious to detection, although even then they weren’t directly visible. Instead, researchers had to rely on the Sunyaev-Zel’dovich effect, which is when light from the big bang itself is scattered by passing hot gas. So in the end, the teams were only able to see strands of scattered light connecting two galaxies, but that was enough to confirm the presence of otherwise invisible matter.

This doesn’t solve all of our dark matter mysteries, but it does account for a significant chunk of what was otherwise unconfirmed sources of gravity. There are hypothesis about what other kinds of particles are helping fill the cosmic void, but for now it’s nice knowing that we’ve been on the right track with our understanding of gravity so far, and that only half the universe’s mass can’t be explained. Yet.

Source: Half the universe’s missing matter has just been finally found by Leah Crane, New Scientist

On October 8th, 2017 we learned about

A dearth of debris around Pluto hopefully means less danger for New Horizons’ future fly-bys

There are times when NASA really looks forward to finding nothing. It’s not that anyone was getting tired of seeing new planets, or that a null result would somehow save anyone the trouble of writing up their findings, especially considering the fact that scientists actually wrote 38 pages about how much nothing they found in the space around Pluto. Pluto of course has a sizable moon in Charon and a thin atmosphere, but importantly, when the New Horizons flew by in 2015, the spacecraft didn’t have to worry about dodging icy debris floating near the dwarf planet.

Hunting for hazards

We’ve never seen evidence that Pluto had rings of debris, but we never really got close enough to see all that much detail in before New Horizons arrived to give us a better look at. The large gas giants in the outer solar system, like Saturn and Neptune, all have rings made of rock and ice, suggesting a lot of loose objects are either floating through space or being created near those planets. If Pluto followed this trend, it could have meant that New Horizons would have been flying into a very dangerous situation, since even a small pebble could rip through the spacecraft at the relative speed of 36 thousand miles-per-hour. Just to be on the safe side, a mission control team nicknamed the “Crow’s Nest” was tasked with examining every new view of Pluto for any flicker of light in New Horizon’s path that might lead to trouble.

While flying over Pluto, scientists noticed that something else was relatively absent. The dwarf planet didn’t have nearly the number of impact craters that you might expect for an object that size. As the spacecraft passed over Pluto, teams kept looking for signs of debris that would now be silhouetted against light from the Sun. With that search also coming up empty handed, it suggests that the outer solar system is relatively empty, or at least consolidated in a way that you don’t find around our other planets.

Scanning for MU69’s scraps

Aside from hinting at larger trends about the composition of our solar system, there are practical reasons that this is good news for New Horizons. On January 1, 2019, the spacecraft will fly by its next target, an 18-mile-long object called 2014 MU69. With the clear skies found over Pluto, NASA hopes that there won’t be much to run into as New Horizons travels deeper into the Kuiper Belt. However, there’s a chance that MU69 might be actually be two objects in a tight orbit around each other, to the point of making physical contact. With this possible source of debris drawing closer, the Crow’s Nest team is back at work, looking out for tiny hazards before they become big problems.

Source: Why it’s good news that Pluto doesn’t have rings by Lisa Grossman, Science News

On September 21st, 2017 we learned about

OSIRIS-REx spacecraft buzzes the Earth for a course-correcting boost to Bennu

After a year in space, the OSIRIS-REx spacecraft is returning to Earth for a very brief, friendly shove. To properly align with the asteroid Bennu, which is traveling a very similar orbital path to our planet, OSIRIS-REx needs to adjust its heading by around 6°. Rather than burn a bunch of fuel to push itself in the right direction, the spacecraft will come up behind our planet and borrow some energy in the form of a tug from the Earth’s gravity. This should line it up properly for the next phase of its mission, plus give us a chance to practice tracking small objects moving very quickly in our planet’s direction.

The idea of using a planet’s gravitational pull to adjust a spacecraft’s course isn’t new. Many other probes we’ve sent into space, including Cassini, Juno and both Voyagers, have used what’s often referred to as a gravitational assist maneuver to both adjust their heading and speed up or slow down to be better oriented to reach their destinations. As the craft approaches the planet, it essentially starts to fall towards that larger body. However, thanks to careful alignment and high speeds, spacecraft can get a pull without being completely pulled out of the sky, careening onward past the planet without burning fuel. These moments can sometimes be a chance to take new measurements of the assisting planet, but often, as with OSIRIS-REx’s pass on Friday, instruments are turned off to avoid any chance of interference with the change in velocity.

Fly-by photo-op

That’s not to say that OSIRIS-REx is only coming by to steal a tiny bit of Earth’s orbital energy without giving us anything in return. Around four hours after OSIRIS-REx zips by us, it will test cameras and two spectrometers on both the Earth and the Moon. Even after it’s moved away from its closest proximity of 10,710 miles, the spacecraft will still be within range to make some measurements for around 10 days. So if all goes well, we should be getting around 1,000 postcards of our own planet and Moon from OSIRIS-REx’s brief visit.

Teams in Australia will also be taking pictures from the ground. OSIRIS-REx will be mostly buzzing by Antarctica, so only Australians will have a chance to see it at its lowest altitude. Even then, the small craft won’t be easy to spot, although that makes it a good target to practice tracking similarly-sized meteors. The Desert Fireball Network, with help from citizen scientists in Fireballs in the Sky, aim to build a network of cameras around the world to track small meteors in our cosmic neighborhood. By taking photos from a variety of locations, they should be able to plot the course of an object like OSIRIS-REx in 3D. The fact that we know OSIRIS-REx’s route already makes this a great chance to check if the system is working designed.

Once the photos and measurements come in from this flyby, OSIRIS-REx’s next big moment will be in about another year. In August 2018, the spacecraft will be in range to begin syncing itself closely to Bennu, preparing to capture a small piece of the asteroid. We won’t get our hands on those samples until 2023, but souvenirs are more exciting than postcards, so it should be worth the wait.

Source: OSIRIS-REx Earth flyby: What to Expect by Emily Lakdawalla, The Planetary Society

On September 18th, 2017 we learned about

Super-heated exoplanet is dark due to its atmosphere’s energy absorption

There is a dark object closely orbiting the star WASP-12A, circling it close to every 24 hours. This object reflects almost no light, making it as dull and black as new asphalt, and thus rather difficult to see in the visible spectrum. It’s not dark matter, nor is it a black hole in the making. Instead, it’s simply an extremely overcooked planet. Rather than reflecting light off its atmosphere into space so we can see it, the hydrogen and helium miasma that surrounds planet WASP-12B absorbs nearly every bit of energy its star throw at it, further fueling its extreme temperatures and eventual destruction.

WASP-12B is what’s known as a “hot Jupiter,” because it’s two-times larger than our solar system’s premier gas giant, while also holding above average temperatures in its atmosphere. However, that title really doesn’t capture the nature of WASP-12B’s atmosphere, which is 4,600° Fahrenheit one side, and around 2,600° Fahrenheit on the other. The large disparity is because the planet is tidally locked, meaning the “day” side of the planet is always facing its star, while the “night” side always dark. This arrangement means that temperatures have a harder time equalizing, since winds flowing from one side to the other can only do so much to mitigate the effects of constant heat exposure. At this point, the molecules in the atmosphere are thought to have been broken down to more basic atomic states, leaving no molecules to bond into materials that could potentially reflect any of the incoming solar energy.

Minimal registered reflection

The amount of light an object reflects is called albedo, and WASP-12B never gets higher than 0.064. To put it another way, this means that 94 percent of the energy from the star WASP-12A gets trapped in the planet’s increasingly shattered atmosphere. For comparison, the Earth only absorbs around 70 percent of the Sun’s energy each day, and our rotation helps keep that from being overly concentrated in a single location.

Some energy is reflected though, which is how the Hubble space telescope was able to see the bleak ball of heat in the first place. Once the planet was in it’s brief but daily position where it’d be illuminated by its star, the telescope was able to see and measure the energy reflected off WASP-12B’s daytime side. The light that came back was appropriately slightly red, compatible to the glow of red-hot metal.

My third grader asked: How does the planet exist close to the star at those temperatures? Why wouldn’t it be destroyed like we would be?

Well, the short answer is that WASP-12B is being destroyed, just slowly. Hubble’s Cosmic Origins Spectrograph has found that material from the black ball of heat is being cooked off the atmosphere and absorbed into the star. There aren’t estimates on how long this will continue, but as planet shrinks its inertia will likely decrease, making it even more likely to be consumed by WASP-12A.

Source: Hubble observes pitch black planet, Hubble Space Telescope

On September 14th, 2017 we learned about

How Cassini’s 13 years of study transformed our understanding of Saturn’s natural satellites

Friday, September 15, 2017, will be the first time my kids wake up without a spacecraft near Saturn. Launched in 1997, the Cassini spacecraft has had its mission extended twice, but a dwindling fuel supply is requiring that the orbiter be permanently added to Saturn’s atmosphere in a “disassembly” procedure expected to rapidly occur at around 70,000 miles-per-hour. This fiery end will give Cassini a unique shot at collecting a final bit of data, but is driven primarily to avoid the risk of the spacecraft accidentally damaging some of the moons we now know might be home to life. It should be expected that spending 13 years around Saturn would enhance our understanding of that part of the solar system, but it’s fair to say that Cassini revealed more than anyone was expected when the mission was first planned in the early 1980s. For now, my kids asked that I mainly focus on the moons.

Imperfect views before Cassini’s visit

Again, from our current vantage point that’s been filled with years of daily snapshots of a great gas giant and it’s ever growing list of moons, it may be hard to remember how little we knew of the outer solar system in the past. To back up a bit further, it’s worth mentioning the spacecraft’s namesake, Jean-Dominique Cassini, an astrologer-turned-astronomer that discovered gaps in Saturn’s rings, as well as the moons Iapetus, Rhea, Tethys and Dione. At the behest of King Louis XIV, Cassini joined the Acadèmie Royale des Sciences in 1669, going on to become the director of the Observatoire de Paris in 1671. Beyond the connections to Saturn, it was thought that invoking Cassini for this mission to space would help garner support from the European Space Agency (ESA), which did indeed prove instrumental in getting the project off the ground.

Our view of Saturn didn’t change much until the Voyager 1 spacecraft flew by the planet in 1980. Instead of the inert lumps of icy rock people had once imagined, we saw hints of a diverse group of moons, begging for more investigation. Titan, for instance, was covered in a thick atmosphere, but Voyager 1 didn’t have any instruments that could see through the clouds to know what was below. This became a key part of the Cassini mission design, with the ESA taking the lead in designing the Huygens lander that would later be dropped on the surface of Titan. This collaboration, and some of the aforementioned goodwill that lead to some influential lobbying efforts by the ESA, became critical to seeing Cassini completed, as the project was almost canceled multiple times before it’s launch in 1997.

Surveying Saturn’s many moons

Touching down on Titan

Once launched, Cassini started sending back mountains of data that opened our eyes to all kinds of new possibilities around Saturn. The Huygens probe successfully visited Titan, revealing that the mix of surface liquids and organic molecules covering the moon might potentially be home to some form of life. In retrospect, dropping a lander into that environment wouldn’t be allowed today, but that’s only because we have now seen the surface of the moon, complete with lakes, riverbeds, dunes, weather and more.

Enceladus’ great geysers

The next eye-popping moon was less expected. Enceladus was observed in 2005 spraying saltwater geysers out of its surface into space. This unexpected site has since catapulted this small moon to the top of researchers’ wish-list of locations to revisit, as these geysers indicate that the moon is even more likely to be home to life than Titan. The salty spray has also been linked to Saturn’s giant “E” ring, which is now believed to be made primarily of ejected ice from Enceladus.

Rings’ debris mashes into moons

Beyond potentially habitable satellites, Cassini has had time to fill in gaps about other strange moons around Saturn. Iapetus had been a mystery for some time, as it seemed to be half white and half black. The detailed data from Cassini helped explain this appearance, and it was determined that dark red debris from another moon, Phoebe, was essentially painting Iapetus’ surface. So the dark side was heat-collecting dirt, and the light side was ice that hadn’t been painted enough to melt. The moon also had an odd ridge around it’s equator which is now thought to be the result of bombardment and debris collection. It’s not the only moon to exhibit this strange shape, as Daphnis and Pan seem to also have equatorial build-ups of their own.

Six moons seen for the first time

Daphnis has caught scientists’ eyes for more than it’s slightly oblong shape. The tiny moon is one of many that have been found in gaps between Saturn’s rings, although it still interacts with them. As the small bits of rock and debris move by Daphnis, the moon’s gravity creates waves in the rings shape. Other moons’ interactions aren’t quite so graceful though. In 2013, a moonlet tentatively known as “Peggy,” after the discoverer’s mother-in-law, was observed forming on the edge of Saturn’s “A” ring, only to have apparently been smashed by another object by the time researchers checked again in 2015. Even with that loss, Cassini has nonetheless discovered six new named moons around Saturn, including Methone, Pallene, Polydeuces, Daphnis, Anthe, and Aegeon, bringing the count up to 53, with a few still lingering as “provisional.”

Carrying on after Cassini’s crash

All of the above barely scratches as the surface of the research Cassini has made possible (especially since this post basically ignores what was learned about Saturn itself!) Nearly 4,000 papers have been published using data from the spacecraft, with more yet to come. It will wind down though— as I write this, the final photos have already been taken so the spacecraft can prioritize more easily streamed data, like individual measurements, in its final moments above Saturn. For our next look at Saturn and its moons, we may have a wait on our hands. New missions to Saturn are still in early planning stages at best, but hopefully running out of interplanetary postcards from Cassini will help spark demand for further exploration, just as the Voyager 1 mission sparked ideas for Cassini itself. After 13 years of amazing exploration, we’ve seen too much to never visit again.

My kids asked: Why are you crying, Daddy?

It’s hard to explain, but this feels much more intense than when MESSENGER was crashed into Mercury, or even when Rosetta was permanently parked on Comet 67P. The fact that Cassini has been in space for over half my life, and my children’s entire lives, has definitely made it seem like a significant change in the world, er, solar system. Saying goodbye sucks. The fact that many of the reports on Cassini’s Grand Finale mission are framed as tear-jerking, heroic sacrifices certainly doesn’t help. It certainly didn’t help my kids, who both decided to start crying when hearing about exactly how Cassini would break up, with my four-year-old repeatedly asking “but why are they breaking the satellite?!”

Beyond that, reading about the success of this product of cooperation and curiosity is really heartening, and it’s always good to have examples of humanity being awesome. (And make no mistake— this has been awesome.) However, having no plan for a return yet makes me very nervous. It’s not that I have a line of research I need investigated or investments in aerospace, but that I want to know that our society will still invest in broadening our horizons, simply as an affirmation of our values. I do take some solace in the fact that Cassini was almost canceled, and yet has beat expectations right and left, so I have to believe that I’ll get to see better close-ups of Enceladus before too long. In the mean time, it’s probably time to check in with Juno

Source: Cassini's Grand Tour by Nadia Drake and Brian T. Jacobs, National Geographic

On September 11th, 2017 we learned about

Scientists plan to scour the South Pole for that continent’s missing meteorites

In addition to Disneyland, my daughter is now asking for a trip to Antarctica. It’s not that she loves the cold or needs to see some penguins, but because it’s a great place to collect rocks… that fell from space. While the entire planet is estimated to be littered with tens of thousands of meteorites per year, they’re usually landing in places that make them very hard to recover, like the oceans. Antarctica then provides a special opportunity, as there is little to obscure your view of a dark meteorite nestled in the white snow and ice. It’s not a total cake walk though, as scientists have noticed that a portion of the expected meteorites in Antarctica seem to be missing.

Iron in the ice

Based on surveys of other barren areas of Earth, like sandy deserts, researchers have estimates for the amount of space rocks they’d expect per square mile of land per year. Antarctica has it’s share of many of these rocks, suggesting that the southernmost continent is not being picked over by the collectors my daughter wants to join. However, the iron-based meteorites don’t turn up in the expected quantities, and researchers are planning to scour the South Pole to see where they’ve all gone.

The current hypothesis is that the 4.8 percent of meteorites that can’t be accounted for have somehow submerged themselves deeper into the Antarctic ice. It may be as straightforward as the dark iron metal collecting heat in the sun, and melting a hole in the snow and ice before being buried. The hope is to clear this up with metal detectors, because if these meteorites aren’t there, there’s a much bigger mystery to solve about why the distribution of falling meteors would be uneven around the South Pole.

Pieces of planets

If the missing meteorites are simply sitting under a layer of ice, there’s still a lot to learn from them. The iron in a meteorite is usually very old, possibly dating back to the formation of our solar system. As proto-planets congealed and collided, pieces of rock and iron would have broken off to float through space, at least until they collided with something bigger like the Earth. If these meteorites can be recovered, the hope is that they can be used like a time capsule to see what the chemistry of our solar system once looked like.

My third grader asked: If I did find a meteorite, could I keep it?

That depends. In the United States, if you find a rock from space on private property, it’s that property-owner’s rock, so you have to negotiate with them. If the meteorite turns up on public land, they technically belong to the federal government. You might then need permits specific to your intended use of the meteorite, although how that’s enforced apparently depends a lot on how the local Bureau of Land Management operates.

As for meteorites in Antarctica, things operate differently since technically no government runs that continent. The Antarctic Treaty from 1959 does allow the collection of specimens for scientific study, and nobody is allowed to sell them. This is apparently a great way for research institutions to get access to meteorites without worrying about breaking their acquisitions budget.

Source: The quest to solve the mystery of Antarctica's 'lost meteorites' by Bryan Nelson, Mother Nature Network

On September 6th, 2017 we learned about

Super-sized solar flares shoot down electromagnetic signals on Earth

There’s another storm coming. For better or for worse, it won’t be delivering more wind, rain, flooding or even fire, as it instead pelted us with various forms of radiation, and possibly a good blast of ionic particles moving at over a million miles an hour as well. Like other big storms, the full extent of the event will be better understood once things have returned to normal, but in the mean time, NASA is keeping a close eye on the Sun where this particular blast of activity originated.

Enormous explosions

The specific disruption that was detected by the Solar Dynamics Observatory was a pair of solar flares, early in the morning of September 6. Flares are the result of warping magnetic fields in the Sun that build up over time, then suddenly release a glut of potential energy. The resulting burst heats surrounding solar material by millions of degrees, and sends out a wave of radiation, from large x-rays to tiny, fast gamma rays. Flares are categorized by their size and intensity as either a C-, M-, or X-class, depending on the intensity of emitted x-rays. This morning’s events were certainly heavyweights, with the first flare being measured as an X2.2 and the second an X9.3, the most intense explosion recorded in our solar system since 1997.

The fallout from these explosions was noticeable, but brief. Some of the energy from a flare can reach the Earth at the speed of light, arriving eight minutes after the magnetic field collapses on the Sun. Most of this radiation likely intercepted by our atmosphere before it could hit us, but that’s not easy on many of the technologies we rely on. Disruptions to the ionosphere can interrupt radio and GPS signals, and a one-hour blackout of radio and navigation signals was noted around 8:02 am EST this morning.

The corona as a plasma cannon

The bigger question at this point isn’t about the flares, but the chance that a coronal mass ejection (CME) took place at the same time. Confirmation is still needed, but the second flare possibly coincided with a blast of plasma, or magnetized particles similar to a super-heated gas, being sent towards Earth. Those particles may arrive at our doorstep in the next few days, and can trigger a bit more than some fuzzed GPS signals.

When CMEs come into contact with Earth’s own magnetic field, the collisions of charged particles and give off lights that we know as auroras, or Northern and Southern Lights. They can also interact with a wider variety of electronic devices, causing interference in radio signals, skewing GPS readings, and even overloading sensitive equipment. In 1989, the geomagnetic storm from a CME even caused blackouts in Canada. Even if this morning’s flares did include a CME, utilities can prepare for potential problems, minimizing the effects of a geomagnetic storm over the next few days.

The storm before the calm?

Like other weather patterns, there is a seasonal aspect to flares and CMEs. The Sun is actually moving towards the lower-intensity portion of it’s 11-year-cycle, promising a bit less activity in the near future. Of course, this morning’s activity included the most intense flare of the current cycle, so there’s no promise that the “off season” will necessarily be completely quiet.

Source: Two Significant Solar Flares Imaged by NASA's SDO by Karen C. Fox, NASA News

On September 5th, 2017 we learned about

Oversized asteroid’s unusual flyby reveals two miniature moons in orbit

Two new moons were just discovered in our cosmic backyard, although they won’t be there for long. The two unnamed bits of rock just careened past Earth on September 1st, coming as close as 4.4 million miles away. The reason for their hurry is that, as moons, orbit a larger body, which in this case is the asteroid known as 3122 Florence. That flyby was was probably the best view we’ll get of these new moons for at least 500 years, since even though Florence’s orbit around the Sun is close to our own, we don’t really share the same space all that often.

A close, but comfortable, look

Obviously, 3122 Florence isn’t as big an object as Mars, our Moon, or even the dwarf planet Ceres. Still, at around 2.7 miles across, Florence does stand out as being the biggest rock we’ve ever seen zipping by the Earth like this, although there are at least nine others in the “neighborhood” that we know of around this size.) There’s some comfort to be found in this amount of space between our planet and these neighbors though, as Florence is more than large enough to basically end life as we know it if it were somehow redirected to collide with Earth.

As predicted though, Florence maintained its course around the Sun, never getting closer than 18 times the distance to the Moon. This meant that nobody had to worry about saving the world, and could instead work on learning about this asteroid from the convenience of our own observatories. Before Florence’s arrival, nobody knew exactly what to expect, although a Moon was a definite possibility. The fact that the asteroid arrived as a triplet, that is, with two moons between 300 to 1,000 feet across was a bit of a bonus.

Convenient data collection

Seeing the relatively small objects with optical telescopes was tricky, since at those distances something 2.7 miles across doesn’t reflect all that much light. Instead, astronomers took advantage of the asteroid’s proximity, and collected data with radar imaging. They were able to pick up the orbits of the mini-moons, as well as get a hint of a bulge along Florence’s equator. More analysis is needed, but we already have estimates about the two moons’ orbits, thought to be around eight and 22 hours. Florence itself was seen to rotate rather quickly, finishing a turn ever 2.4 hours.

With the number of instruments pointed at our brief visitor, this encounter may yield more information in the coming months. While NASA is working on missions to catch up to asteroids further out in space, this was an unusual moment when the mission safely delivered itself to us.

Source: Asteroid Florence Has Two Moons by Kelly Beatty, Sky & Telescope