M42 by NASA Hubble
“The stars, like dust, encircle me In living mists of light; And all of space I seem to see In one vast burst of sight.”
—
Isaac Asimov
On Sept. 15, 2017, our Cassini spacecraft ended its epic exploration of Saturn with a planned dive into the planet’s atmosphere–sending back new science to the very last second. The spacecraft is gone, but the science continues!
New research emerging from the final orbits represents a huge leap forward in our understanding of the Saturn system – especially the mysterious, never-before-explored region between the planet and its rings. Some preconceived ideas are turning out to be wrong while new questions are being raised. How did they form? What holds them in place? What are they made of?
Six teams of researchers are publishing their work Oct. 5 in the journal Science, based on findings from Cassini’s Grand Finale. That’s when, as the spacecraft was running out of fuel, the mission team steered Cassini spectacularly close to Saturn in 22 orbits before deliberately vaporizing it in a final plunge into the atmosphere in September 2017.
Knowing Cassini’s days were numbered, its mission team went for gold. The spacecraft flew where it was never designed to fly. For the first time, it probed Saturn’s magnetized environment, flew through icy, rocky ring particles and sniffed the atmosphere in the 1,200-mile-wide (2,000-kilometer-wide) gap between the rings and the cloud tops. Not only did the engineering push the spacecraft to its limits, the new findings illustrate how powerful and agile the instruments were.
Many more Grand Finale science results are to come, but today’s highlights include:
Complex organic compounds embedded in water nanograins rain down from Saturn’s rings into its upper atmosphere. Scientists saw water and silicates, but they were surprised to see also methane, ammonia, carbon monoxide, nitrogen and carbon dioxide. The composition of organics is different from that found on moon Enceladus – and also different from those on moon Titan, meaning there are at least three distinct reservoirs of organic molecules in the Saturn system.
For the first time, Cassini saw up close how rings interact with the planet and observed inner-ring particles and gases falling directly into the atmosphere. Some particles take on electric charges and spiral along magnetic-field lines, falling into Saturn at higher latitudes – a phenomenon known as “ring rain.” But scientists were surprised to see that others are dragged quickly into Saturn at the equator. And it’s all falling out of the rings faster than scientists thought – as much as 10,000 kg of material per second.
Scientists were surprised to see what the material looks like in the gap between the rings and Saturn’s atmosphere. They knew that the particles throughout the rings ranged from large to small. They thought material in the gap would look the same. But the sampling showed mostly tiny, nanograin- and micron-sized particles, like smoke, telling us that some yet-unknown process is grinding up particles. What could it be? Future research into the final bits of data sent by Cassini may hold the answer.
Saturn and its rings are even more interconnected than scientists thought. Cassini revealed a previously unknown electric current system that connects the rings to the top of Saturn’s atmosphere.
Scientists discovered a new radiation belt around Saturn, close to the planet and composed of energetic particles. They found that while the belt actually intersects with the innermost ring, the ring is so tenuous that it doesn’t block the belt from forming.
Unlike every other planet with a magnetic field in our Solar System, Saturn’s magnetic field is almost completely aligned with its spin axis. Think of the planet and the magnetic field as completely separate things that are both spinning. Both have the same center point, but they each have their own axis about which they spin. But for Saturn the two axes are essentially the same – no other planet does that, and we did not think it was even possible for this to happen. This new data shows a magnetic-field tilt of less than 0.0095 degrees. (Earth’s magnetic field is tilted 11 degrees from its spin axis.) According to everything scientists know about how planetary magnetic fields are generated, Saturn should not have one. It’s a mystery physicists will be working to solve.
Cassini flew above Saturn’s magnetic poles, directly sampling regions where radio emissions are generated. The findings more than doubled the number of reported crossings of radio sources from the planet, one of the few non-terrestrial locations where scientists have been able to study a mechanism believed to operate throughout the universe. How are these signals generated? That’s still a mystery researchers are looking to uncover.
For the Cassini mission, the science rolling out from Grand Finale orbits confirms that the calculated risk of diving into the gap – skimming the upper atmosphere and skirting the edge of the inner rings – was worthwhile.
Almost everything going on in that region turned out to be a surprise, which was the importance of going there, to explore a place we’d never been before. And the expedition really paid off!
Analysis of Cassini data from the spacecraft’s instruments will be ongoing for years to come, helping to paint a clearer picture of Saturn.
To read the papers published in Science, visit: URL to papers
To learn more about the ground-breaking Cassini mission and its 13 years at Saturn, visit: https://www.nasa.gov/mission_pages/cassini/main/index.html
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
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.
Plesiosaurus skeleton from the Houston Natural History Museum!
(WARNING: Don’t try any of this on Earth—except the last one.)
Janssen aka 55 Cancri e
Hang your steak on a fishing pole and dangle your meat over the boiling pools of lava on this possible magma world. Try two to three minutes on each side to get an ashy feast of deliciousness.
Dimidium aka 51 Pegasi b
Set your grill to 1800 degrees Fahrenheit (982 degrees Celsius) or hop onto the first exoplanet discovered and get a perfect char on your hot dogs. By the time your dogs are done, it’ll be New Year’s Eve, because a year on this planet is only four days long.
HD 40307 g
Super air fry your duck on this Super Earth, as you skydive in the intense gravity of a planet twice as massive as Earth. Why are you air frying a duck? We don’t know. Why are you skydiving on an exoplanet? We’re not judging.
HAT-P-11b
I’ve got steaks, they’re multiplying/and I’m looooosing control. Cause the power this planet is supplying/is electrifying!
Sear your tuna to perfection in the lightning strikes that could flash across the stormy skies of this Neptune-like planet named HAT-P-11b.
Kepler-186f
Tired of all that meat? Try a multi-colored salad with the vibrant plants that could grow under the red sun of this Earth-sized planet. But it could also be a lifeless rock, so BYOB (bring your own barbecue).
Kepler-70b
Don’t take too long to prep your vegetables for the grill! The hottest planet on record will flash-incinerate your veggies in seconds!
WASP-12b
Picture this: You are pressure cooking your chicken on a hot gas giant in the shape of an egg. And you’re under pressure to cook fast, because this gas giant is being pulled apart by its nearby star.
Kepler-16b
Evenly cook your ribs in a dual convection oven under the dual stars of this “Tatooine.” Kick back and watch your two shadows grow in the fading light of a double sunset.
Venus
Order in for a staycation in our own solar system. The smell of rotten eggs rising from the clouds of sulfuric acid and choking carbon dioxide will put you off cooking, so get that meal to go.
Earth
Sometimes the best vacations are the ones you take at home. Flip your burgers on the only planet where you can breathe the atmosphere.
Grill us on Twitter and tell us how bad our jokes are.
Read the full version of this week’s ‘Solar System: 10 Things to Know’ Article HERE.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
Video description:
Titanites lived during the Late Jurassic Period and had a shell diameter of around 137 centimetres! surprisingly it wasn’t the largest ammonoid, as some species such as Parapuzosia could get over twice as large!
There were also some plant fossils around the area of this site!
Amateur astronomer, owns a telescope. This is a side blog to satiate my science-y cravings! I haven't yet mustered the courage to put up my personal astro-stuff here. Main blog : @an-abyss-called-life
212 posts