(by lorenz.weisse)

Venus and the Pleiades

Daphnis and the Rings of Saturn : What’s happening to the rings of Saturn? A little moon making big waves. The moon is 8-kilometer Daphnis and it is making waves in the Keeler Gap of Saturn’s rings using just its gravity – as it bobs up and down, in and out. The featured image is a colored and more detailed version of a previously released images taken in 2017 by the robotic Cassini spacecraft during one of its Grand Finale orbits. Daphnis can be seen on the far right, sporting ridges likely accumulated from ring particles. Daphnis was discovered in Cassini images in 2005 and raised mounds of ring particles so high in 2009 – during Saturn’s equinox when the ring plane pointed directly at the Sun – that they cast notable shadows. via NASA

Decoding Nebulae

We can agree that nebulae are some of the most majestic-looking objects in the universe. But what are they exactly? Nebulae are giant clouds of gas and dust in space. They’re commonly associated with two parts of the life cycle of stars: First, they can be nurseries forming new baby stars. Second, expanding clouds of gas and dust can mark where stars have died.

Not all nebulae are alike, and their different appearances tell us what's happening around them. Since not all nebulae emit light of their own, there are different ways that the clouds of gas and dust reveal themselves. Some nebulae scatter the light of stars hiding in or near them. These are called reflection nebulae and are a bit like seeing a street lamp illuminate the fog around it.

In another type, called emission nebulae, stars heat up the clouds of gas, whose chemicals respond by glowing in different colors. Think of it like a neon sign hanging in a shop window!

Finally there are nebulae with dust so thick that we’re unable to see the visible light from young stars shine through it. These are called dark nebulae.

Our missions help us see nebulae and identify the different elements that oftentimes light them up.

The Hubble Space Telescope is able to observe the cosmos in multiple wavelengths of light, ranging from ultraviolet, visible, and near-infrared. Hubble peered at the iconic Eagle Nebula in visible and infrared light, revealing these grand spires of dust and countless stars within and around them.

The Chandra X-ray Observatory studies the universe in X-ray light! The spacecraft is helping scientists see features within nebulae that might otherwise be hidden by gas and dust when viewed in longer wavelengths like visible and infrared light. In the Crab Nebula, Chandra sees high-energy X-rays from a pulsar (a type of rapidly spinning neutron star, which is the crushed, city-sized core of a star that exploded as a supernova).

The James Webb Space Telescope will primarily observe the infrared universe. With Webb, scientists will peer deep into clouds of dust and gas to study how stars and planetary systems form.

The Spitzer Space Telescope studied the cosmos for over 16 years before retiring in 2020. With the help of its detectors, Spitzer revealed unknown materials hiding in nebulae — like oddly-shaped molecules and soot-like materials, which were found in the California Nebula.

Studying nebulae helps scientists understand the life cycle of stars. Did you know our Sun got its start in a stellar nursery? Over 4.5 billion years ago, some gas and dust in a nebula clumped together due to gravity, and a baby Sun was born. The process to form a baby star itself can take a million years or more!

After billions more years, our Sun will eventually puff into a huge red giant star before leaving behind a beautiful planetary nebula (so-called because astronomers looking through early telescopes thought they resembled planets), along with a small, dense object called a white dwarf that will cool down very slowly. In fact, we don’t think the universe is old enough yet for any white dwarfs to have cooled down completely.

Since the Sun will live so much longer than us, scientists can't observe its whole life cycle directly ... but they can study tons of other stars and nebulae at different phases of their lives and draw conclusions about where our Sun came from and where it's headed. While studying nebulae, we’re seeing the past, present, and future of our Sun and trillions of others like it in the cosmos.

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my favorite genre of photo is “excited scientist lying down next to a very big fossil/animal/object/etc they have found to show off how big it is”

Tarantula Nebula by NASA Hubble

Sunset on Mars by NASA’s Curiosity Rover

Important science info guys.

The Titanoboa, is a 48ft long snake dating from around 60-58million years ago. It had a rib cage 2ft wide, allowing it to eat whole crocodiles, and surrounding the ribcage were muscles so powerful that it could crush a rhino. Titanoboa was so big it couldn’t even spend long amounts of time on land, because the force of gravity acting on it would cause it to suffocate under its own weight.

russia’s lake baikal - the world’s oldest, largest (by volume) and deepest freshwater lake - freezes over for half the year, creating clear, turquoise shards of ice. (photos x, x x, x, x, x) 

“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.