On December 6th, 2017 we learned about

Newly discovered black hole is bafflingly large for being 13 billion years old

When you look at stars in the night sky, you’re not only seeing light from another place, but another time. Space is so vast that even light, moving at the fastest speed we can imagine, takes ages to reach our planet from other parts of the universe. So if you look at our solar system’s closest neighbor, Alpha Centauri, you’re seeing the light emitted by that star over four years ago. Bigger distances thus yield bigger gaps in time, which is how astronomers recently found evidence of a black hole from 13 billion years ago, long before the Earth, or most other planets, even existed.

Finding darkness in ultrabright objects

The light that was detected by wasn’t coming directly from the black hole itself, as those intensely massive objects don’t emit or reflect any light to see (hence their name). Any object that gets too close gets pulled into the black hole, but all that gravity is good for collecting a looser assortment of material in the immediate space around the black hole as well. In the case of this ancient black hole spotted by astronomers, they knew it was there it was surrounded by an ultrabright quasar, a cloud of energy-emitting particles orbiting the black hole at close to the speed of light.

By analyzing the light coming from quasar J1342+0928, the following profile of the black hole was put together. The supermassive black hole was around 800 million times the mass of our Sun, which isn’t surprising since it would have to be large to support a quasar around it. However, when combining that size plus its age, scientists started scratching their heads. How did such huge collection of mass exist only 690 million years after the Big Bang created our universe?

What existed in the early days of the universe?

As far as everyone could understand, there shouldn’t have been that much material in one place to form a giant black hole that early in our universe’s history. The current model is that after the Big Bang occurred, matter was first very energetic, but then calmed down into mostly neutral hydrogen atoms. Each proton and electron pair was balanced, and had no need to interact with its neighbors, meaning no energy was being released anywhere. This time in the universe’s history is known as the Cosmic Dark Ages, because no stars yet existed to emit any light. Everything was essentially inert.

Eventually, gravity started stirring things up. Particles began to clump and collide, forming larger atoms and reactions. New elements were created for the first time, as did collections of mass with enough nuclear activity to start emitting energy, becoming the first stars. As it happens, the light from the newly discovered quasar J1342+0928 was emitted at this time, meaning it existed when the entire concept of “stars” was just getting started.

Too old to be so big?

Which brings us back to how weird this timing is. The nuances of the light from quasar J1342+0928 help narrow down the date of the so-called Cosmic Dawn, but also raises new questions about what the state of the universe was at that time. If stars were still forming for the first time, how was enough matter somehow rounded up already to form a black hole 800 times bigger than our Sun? Smaller black holes are normally created from the collapse of a star, not congealing dust. This doesn’t necessarily contradict the model for the universe’s maturation, but instead has astronomers looking for new ways for black holes to form.


My four-year-old asked: What would happen to a person sucked into a black hole? To a car? To a house? To a… (etc.)

In almost every case, once that object got close enough to the black hole, crossing the so-called event horizon, it would be ripped and stretched to the center of the gravity-producing mass. For instance, if you fell in feet first, your feet would be yanked downwards harder than your head, although overall the experience would probably be very short, as you’d be pulled apart into a molecular “piece of spaghetti” before being crushed into the black hole itself. You’d technically be adding more mass to the black hole too, making it ever-slightly bigger than it was before.

 

Source: Scientists observe supermassive black hole in infant universe, Phys.org

On November 27th, 2017 we learned about

High-speed dust could help spread life throughout outer space

What are the odds that we’re all alien life forms? Even if your family has been in your home town for generations, there’s a chance that all life on Earth originated elsewhere, and was somehow transported to this planet billions of years ago. The idea is known as panspermia, and is usually based around the notion that a large asteroid broken off or expelled from a planet carried some hearty organisms along through space, eventually crashing into Earth where those organisms spread and diversified. A new wrinkle in this model is being suggested now, as simulations have found that a large rock may not have been a necessary component for life to travel— biological particles in a planet’s upper atmosphere may have been able to be launched by dust alone.

While there’s not enough air to breath in space, it’s not a complete vacuum either. In addition to larger and smaller asteroids, there’s a fair amount of dust that either never coalesced into a larger object, or was broken off a larger object in a collision. Researchers from the University of Edinburgh found that some of that dust is zipping along at a brisk 156,586 miles per hour, giving them a significant amount of energy to shove other particles that might be suspended high above a biologically active planet’s surface. For example, if a microscopic organism was suspended 93 miles over the Earth’s surface, around the altitude of auroras, a collision with space dust could knock it past the planet’s gravitational pull towards a new home (assuming it survived the collision.)

What life could survive in space?

Once biological material was on its way, the trip might be easier to survive than you’d think. Some bacteria have been found to survive in the generally hostile environment of outer space, and plants and animals do better than expected as well. However, a living creature wouldn’t be strictly necessary to seed life on a new planet. Even the delivery of organic molecules like amino acids would make a huge difference in kick-starting an ecosystem, some of which have already been linked to meteorites found on Earth. If these molecules could be sent sailing from mere dust as well, then the possibilities really open up for interstellar pollination.

Source: Space dust may transport life between worlds, University of Edinburgh News

On November 15th, 2017 we learned about

Climate models that explain colder conditions on dwarf and exoplanets

As the Earth struggles with atmospheric warming, scientists are finding mechanisms that are actually cooling more distant worlds. Unfortunately, they’re not systems that we could reproduce to deal with our greenhouse gas problem on Earth, but understanding what chills the atmospheres of these distant bodies will likely help with the search for habitable worlds in other solar systems.

Pluto is colder than we calculated

Everybody knows that Pluto is cold, but the dwarf planet still surprised scientists with just how cold it really was. Remote measurements of the elements in Pluto’s atmosphere suggested that the Sun should warm its surface to around -343° Fahrenheit, but that isn’t what the New Horizons spacecraft measured when it flew by in 2015. Instead, more direct measurements found that the atmosphere was a frosty -397° Fahrenheit. Over the last two years, researchers have been looking through the collected data to see what could account for this temperature difference.

The current hypothesis is built around the size of the particles in Pluto’s atmosphere. Most atmospheres are made of gas, meaning the atoms and molecules suspended in the sky are tiny and fairly energetic. Pluto seems to have some larger hydrocarbon particles in the mix though, suspended as solid crystal structures instead of gases. Even though these particles are small enough to be measured in nanometers, they’re big enough to interact with heat from the Sun in an unusual manner. Instead of trapping heat against the dwarf planet’s surface like a greenhouse gas, they’re likely absorbing heat from the Sun and surrounding atmosphere, then radiating that heat back into space. This means that the heat is essentially reflected before it has a chance to warm Pluto up.

Heavy snowfall on a hot planet

While Pluto’s hydrocarbon haze may be an effective heat shield, the exoplanet Kepler-13Ab uses similar mechanisms in even more extreme circumstances. The giant planet has a close orbit around its star, Kepler-13A, and thus doesn’t doesn’t rotate like the Earth does on a daily basis. This leaves one side of the so-called “hot Jupiter” in constant daylight, raising temperatures as high as 5,000° Fahrenheit. The night side is then left in permanent darkness, with temperatures dropping appropriately.

Kepler-13Ab was found to have titanium oxide (TiO) in it’s atmosphere, which by itself isn’t unusual for a gas giant planet. Usually this leads to higher temperatures in a planet’s upper atmosphere, as the TiO acts like a greenhouse gas more or less, collecting and emitting heat. Kepler-13Ab changes that formula thanks to its immense gravity, which is six-times greater than Jupiter’s. So instead of remaining in the sky as gases, the planet is pulling some TiO down on its cold, night side as larger particles, almost like a form of snow. As the snow gets pulled down, it takes some heat away with it, lowering the maximum temperature in the upper atmosphere. Without Kepler-13Ab’s intense gravity, the particles would be more likely to recirculate in the atmosphere again, redistributing heat.

Nobody is planning to visit Pluto or Kepler-13Ab any time soon, but these extreme climates will help us as we search for more temperate planets. Being able to understand all the variables that can influence a planet’s climate, including less obvious factors like gravity and particulate size, will make it easier to identify the more subtle conditions that could make some planets pleasant place for life to take root.

Source: Astronomers discover sunscreen snow falling on hot exoplanet, Phys.org

On October 26th, 2017 we learned about

For the first time, astronomers spot an interstellar asteroid flying through our solar system

Our solar system had a guest this week. A small object, most likely an asteroid, was detected zipping past the Sun, dipping below the orbital plane of our local planets and asteroids, then being rocketed up past the Earth at over 97,000 miles-per-hour. It’s exact path is still being pinned down, but at this point it looks like A/2017 U1 is the first object to be observed passing by our Sun while originating somewhere outside our solar system.

Sharp turn just past the Sun

A/2017 U1 was first spotted by the University of Hawaii’s Pan-STARRS 1 telescope on October 19th. It was actually photographed the night before as well, but it wasn’t recognized as something special until the following day when it’s unusual trajectory was detected and analyzed. Rather than following the orbital plane that most of the objects in our solar system move along, this new object was seen diving almost directly at the Sun, and it was doing so very quickly, at around 56,000 miles-per-hour. This high speed is probably what allowed it to slip past the Sun at inside Mercury’s orbit without getting pulled in the Sun, or being vaporized by its heat.

The Sun’s gravity did get a hold of the small visitor, which is estimated to only be around 525 feet in diameter. Even with all the momentum it had to get past the Sun, that small mass was whipped around in a wide, hyperbolic orbit. This means that rather than continue straight through our solar system, the asteroid went “beneath” the planets’ orbital plane then curved around to fly back “up” between Earth and Mars. The hyperbolic shape of this path is open enough that A/2017 U1 isn’t expected to ever return, basically being accelerated in a gravity assist from the Sun without getting caught in a permanent orbit.

First observed object without an obvious orbit

Obviously, we’re not going to get a ton of data about this small rock that, as of this writing, is already over 31 million miles away from Earth. Still, even during its quick visit, we were able to observe it enough to determine that A/2017 U1 is most likely an asteroid, and not a comet as originally assumed. Beyond its physical characteristics, simply spotting this object is a big step for astronomers. With the mind-boggling number of objects in the universe, it’s long been assumed that there must still be some objects that weren’t caught in orbit around larger planets or stars, traveling between solar systems with no real point of origin to speak of. Scientists have observed at least one comet that was in the process of exiting our solar system thanks to a push from Jupiter’s gravity, but that comet may have been home grown. A/2017 U1 finally provides prove that this untethered objects are out there.

Source: Astronomers Spot First-Known Interstellar “Comet” by Kelly Beatty, Sky & Telescope

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