Prometheus And Pandora Shepherd Saturn’s F Ring Into Shape

“Cassini's own discoveries were its demise.”

– Earl Maize, its project engineer @ JPL

current mood: emotional about a space probe

Cassini is the first spacecraft that was destroyed not from malfunction, or as a necessary end result of its mission… but out of love.

The probe was running out of propulsion fuel, but there’s no reason it couldn’t have been pushed into a stable orbit from where it could collect data and send back pictures for a long while yet.

Except it had detected that one of Saturn’s moons held liquid water and organic compounds: a world that might support life. A world that is, at the least, dreaming of life.

There is no orbit stable enough to be certain that the probe, carrying radioactive batteries and Earth’s bacteria, would never have come into contact with Enceladus. A delicate island of alien life could have been snuffed out or overrun. The sheep could have eaten the rose.

So instead - for the love of this fragile possibility, this potential that might yet never be realized - Cassini was brought into a final, intimate tango with Saturn.

But of course, all space probes are built for the sake of awe, which is nearly love. Science is rational, but scientists are driven to understand the universe just as the religious strive to know the face of God.

The Cassini probe was a 4 billion dollar machine for understanding Saturn. And yesterday, two decades after it launched from our planet, it was destroyed while sending us information about Saturn it never could have gathered from a distant, stable orbit: advancing its purpose, even though it would be consumed.

After about a decade of slowly making friends with all the local crows in our neighborhood by feeding them peanuts when we go out walking, and putting peanuts out on our porch when they’re watching us, about three years back a pair of crows started bringing their fledgling by our porch to get peanuts. He was nervous at first but they showed him that it was safe and led him through the steps of cautiously getting nuts. Like one of his parents (we’re using male pronouns out of laziness, we can’t actually tell the gender of any of the crows), he has a funny habit of ruffling up his feathers into a big puff-ball, something we’ve really only seen this one and his parent do. We called his parent Fluffy because of this habit, so the fledgling was dubbed Fluffy Junior, often called just Junior.

Junior grew up coming by our porch for peanut treats, and following Jack and me when we go out walking. He’s easy to pick out because he’s far less skittish around us than any of the other crows who come to us for treats, and because he’s continued to do the fluff-ball thing. At first he came along with his parents, and then eventually just him, and then last winter he started bringing another crow along with him who was a lot more nervous around us than Junior or his parents had ever been.

Then for awhile this spring, we were only seeing Junior or his very skittish mate, never both of them together, and about two weeks back we finally found out why – Junior has a fledgling! They brought the baby over to the rooftop that’s across from our porch and fed him there, within easy access of the porch treats. The crow we’ve known since he was a baby now has a baby of his very own, and is carrying on the tradition of introducing the baby to us young.

So today we could hear Junior and his mate feeding the baby across the way – and if you’ve never heard crow fledglings being fed, it’s a very distinctive noise that sounds like a crow is being loudly strangled, and if you see it in process, you’ll notice that one crow has a much smaller beak that opens much wider and is bright red on the inside. When you know what to listen and look for, you can pretty easily spot fledglings being fed this time of the year, and often hear it from as much as a block away.

We want to encourage Junior to keep bringing his mate and their baby over to our place (and hopefully outlast the work-from-home era of our hateful neighbor who comes outside and claps at the birds when they make too much noise), so we put out some peanuts and a little bit of cheese for them, which is their absolute all time favorite treat. 

We figured Junior or his mate would get the food and continue to feed their baby on the roof like they’ve done frequently since the beginning of the month, but instead the entire family of three flew over and landed on our porch, and fed the baby right there, about four feet from our door, while Jack and I hid behind the curtains to get a look without spooking them. 

That’s a show of trust that not even Junior’s parents attempted, and it’s so exciting to think that this third generation of this little family will grow up that comfortable with being so close to us. They’re still rightfully skittish about being watched too closely, and we would never try to approach them or touch them, but it is lovely to get to see them behaving so calmly from such a close distance.

Gosh I love my crows.

there are a lot of ai tropes. i chose the six that i love most, and i've turned them into a quiz.

ten questions, six results. no pop culture.

Peaceful Ethereal Piano Music 🎹 Spotify Playlist

Look at the bottom gif! The long tentacles are pushed out and parallel to each other while the jelly is motionless. This behavior is predatory, which means that the Marianas Trench Jelly is set in attack mode! 

Read more about the 2016 discovery of the Marianas Trench Jelly

The Horsehead Nebula : Sculpted by stellar winds and radiation, a magnificent interstellar dust cloud by chance has assumed this recognizable shape. Fittingly named the Horsehead Nebula, it is some 1,500 light-years distant, embedded in the vast Orion cloud complex. About five light-years “tall”, the dark cloud is cataloged as Barnard 33 and is visible only because its obscuring dust is silhouetted against the glowing red emission nebula IC 434. Stars are forming within the dark cloud. Contrasting blue reflection nebula NGC 2023, surrounding a hot, young star, is at the lower left of the full image. The featured gorgeous color image combines both narrowband and broadband images recorded using several different telescopes. via NASA

The Ammonoids The Ammonoids are a subclass of cephalopods that inhabited the oceans from the Devonian some 416 million years ago until they went extinct some 65 million years ago. The species evolved and dispersed rapidly around the world and so are some of the best guide fossils for dating the strata in which they are found.

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Persisting hexagonal storm at Saturn`s North Pole

QUETZALCOATLUS

Quetzalcoatlus goes down in history as the largest flying organism of all time, with a wingspan of 12 metres, which is larger than some planes. Quetzalcoatlus was the undisputed king of the Late cretaceous skies, so it seems fitting that its name is derived from an Aztec god, Quetzalcoatl. Although its wingspan is impressive, Quetzalcoatlus also had a huge 2.5 metre long skull, that is the average height of an Asian elephant! To get such a huge animal in the air, a complex system of air sacs was needed inside the bones, this meant that Quetzalcoatlus probably weighed no more than 250kg. Quetzalcoatlus, along with many pterosaurs, was originally thought to spend most of its time gliding over the oceans, skimming fish out from the surface of the water with their elongated beaks. However, due to the skull and beak morphology and the presence of fossils far inland it has become more widely accepted that Quetzalcoatlus stalked prey far below on the land. The fore and hind limb morphology of Quetzalcoatlus also suggests that they were competent walkers on the land, they would have stood up to 3 metres tall. 

The feeding habits of Quetzalcoatlus still remain something of a mystery. It was originally thought to be more of a scavenger, but the blunt beak was unsuited to stripping and picking flesh of a bony creature. It is more likely that Quetzalcoatlus hunted like modern-day storks, stalking the land from the skies above for smaller animals and then swooping down to eat them whole.

The Stellar Buddy System

Our Sun has an entourage of planets, moons, and smaller objects to keep it company as it traverses the galaxy. But it’s still lonely compared to many of the other stars out there, which often come in pairs. These cosmic couples, called binary stars, are very important in astronomy because they can easily reveal things that are much harder to learn from stars that are on their own. And some of them could even host habitable planets!

The birth of a stellar duo

New stars emerge from swirling clouds of gas and dust that are peppered throughout the galaxy. Scientists still aren’t sure about all the details, but turbulence deep within these clouds may give rise to knots that are denser than their surroundings. The knots have stronger gravity, so they can pull in more material and the cloud may begin to collapse.

The material at the center heats up. Known as a protostar, it is this hot core that will one day become a star. Sometimes these spinning clouds of collapsing gas and dust may break up into two, three, or even more blobs that eventually become stars. That would explain why the majority of the stars in the Milky Way are born with at least one sibling.

Seeing stars

We can’t always tell if we’re looking at binary stars using just our eyes. They’re often so close together in the sky that we see them as a single star. For example, Sirius, the brightest star we can see at night, is actually a binary system (see if you can spot both stars in the photo above). But no one knew that until the 1800s.

Precise observations showed that Sirius was swaying back and forth like it was at a middle school dance. In 1862, astronomer Alvan Graham Clark used a telescope to see that Sirius is actually two stars that orbit each other.

But even through our most powerful telescopes, some binary systems still masquerade as a single star. Fortunately there are a couple of tricks we can use to spot these pairs too.

Since binary stars orbit each other, there’s a chance that we’ll see some stars moving toward and away from us as they go around each other. We just need to have an edge-on view of their orbits. Astronomers can detect this movement because it changes the color of the star’s light – a phenomenon known as the Doppler effect.

Stars we can find this way are called spectroscopic binaries because we have to look at their spectra, which are basically charts or graphs that show the intensity of light being emitted over a range of energies. We can spot these star pairs because light travels in waves. When a star moves toward us, the waves of its light arrive closer together, which makes its light bluer. When a star moves away, the waves are lengthened, reddening its light.

Sometimes we can see binary stars when one of the stars moves in front of the other. Astronomers find these systems, called eclipsing binaries, by measuring the amount of light coming from stars over time. We receive less light than usual when the stars pass in front of each other, because the one in front will block some of the farther star’s light.

Sibling rivalry

Twin stars don’t always get along with each other – their relationship may be explosive! Type Ia supernovae happen in some binary systems in which a white dwarf – the small, hot core left over when a Sun-like star runs out of fuel and ejects its outer layers – is stealing material away from its companion star. This results in a runaway reaction that ultimately detonates the thieving star. The same type of explosion may also happen when two white dwarfs spiral toward each other and collide. Yikes!

Scientists know how to determine how bright these explosions should truly be at their peak, making Type Ia supernovae so-called standard candles. That means astronomers can determine how far away they are by seeing how bright they look from Earth. The farther they are, the dimmer they appear. Astronomers can also look at the wavelengths of light coming from the supernovae to find out how fast the dying stars are moving away from us.

Studying these supernovae led to the discovery that the expansion of the universe is speeding up. Our Nancy Grace Roman Space Telescope will scan the skies for these exploding stars when it launches in the mid-2020s to help us figure out what’s causing the expansion to accelerate – a mystery known as dark energy.

Spilling stellar secrets

Astronomers like finding binary systems because it’s a lot easier to learn more about stars that are in pairs than ones that are on their own. That’s because the stars affect each other in ways we can measure. For example, by paying attention to how the stars orbit each other, we can determine how massive they are. Since heavier stars burn hotter and use up their fuel more quickly than lighter ones, knowing a star’s mass reveals other interesting things too.

By studying how the light changes in eclipsing binaries when the stars cross in front of each other, we can learn even more! We can figure out their sizes, masses, how fast they’re each spinning, how hot they are, and even how far away they are. All of that helps us understand more about the universe.

Tatooine worlds

Thanks to observatories such as our Kepler Space Telescope, we know that worlds like Luke Skywalker’s home planet Tatooine in “Star Wars” exist in real life. And if a planet orbits at the right distance from the two stars, it could even be habitable (and stay that way for a long time).

In 2019, our Transiting Exoplanet Survey Satellite (TESS) found a planet, known as TOI-1338 b, orbiting a pair of stars. These worlds are tricker to find than planets with only one host star, but TESS is expected to find several more!

Want to learn more about the relationships between stellar couples? Check out this Tumblr post: https://nasa.tumblr.com/post/190824389279/cosmic-couples-and-devastating-breakups

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