It’s official: Cassini’s mission at Saturn is over. Today, at 6:31 a.m. EDT (10:31 UTC), Cassini entered the atmosphere of Saturn. A little over a minute later it sent its final transmission back to Earth before succumbing to the physical forces of entry. That signal, Cassini’s last piece of data, ended at 7:55 a.m. EDT (11:55 UTC). After over thirteen years in orbit Cassini is now a part of Saturn; its work is done.
About 14 hours earlier Cassini transmitted its final images of Saturn to Earth. You can see some of those below: Read the rest of this entry
Well, the day has come. Today is the last full day that NASA’s Cassini spacecraft will exist, and in fact right now it is on its final path—a grand soaring arc that will send it down into the atmosphere of Saturn itself on the morning of Friday, Sept. 15. It will be the closest to the ringed planet any spacecraft will have ever gotten, but it’s a trip that Cassini will not long survive. It’s the long-planned end of a glorious mission of exploration and discovery—not to mention beauty, art, and inspiration—and while Cassini itself will soon be gone, the enormous amount of data it has gathered in the twenty years since its launch will continue to drive discovery for many, many years to come.
(At least that’s what we’re all telling ourselves to make the loss a bit easier to bear.)
From a “mere” 93 million miles away we’re able to view the surface of our home star the Sun very well with telescopes on Earth and in space…you can even observe large sunspots with your unaided eye (with proper protection, of course.) But the surface details of other stars tens, hundreds, or thousands of light-years away can’t be so easily resolved from Earth. The details are just too fine and get lost in the brilliance of the stars themselves.
But astronomers have now produced the best image yet of the surface of another star beyond our Solar System. Using the European Southern Observatory’s Very Large Telescope Interferometer, located on a high plateau in Chile’s Atacama Desert where the sky is some of the clearest and driest in the world, a team of scientists have mapped the movement of material in the atmosphere of Antares, a red supergiant star 700 times the size of our Sun that shines brightly in the heart of the constellation Scorpius. The observations enabled them to determine how material moves through Antares’ atmosphere and then construct an image of the star itself—the most accurate representation of another star besides the Sun.
It’s August and one of the most highly-anticipated astronomical events of the 21st century is nearly upon us: the August 21 solar eclipse, which will be visible as a total eclipse literally across the entire United States…but that doesn’t mean everywhere in the United States. Totality will pass across the U.S. in a narrow band about 60 miles wide starting along the northern coast of Oregon at 10:18 a.m. local time (PDT) and ending along the coast of South Carolina at 2:48 p.m. EDT. But that’s just totality—the full eclipse event will actually begin much earlier than that and end later, and its visibility won’t be limited to only that path. And while it’ll be happening overhead in the daytime sky you’ll need the right equipment to view it safely, whether you’re in totality or not.
Wait, you say, what’s the difference between totality and…not totality? And how is it caused? And why is this a big deal at all? If you’re wondering those things (and perhaps others) then this post is just for you. Below are answers to some common—and certainly not dumb—questions about the solar eclipse, brought to you by yours truly (with a little help from NASA and other eclipse specialists.)
Saturn’s largest moon Titan is often called an analogy to early Earth, with its thick, chemical-rich atmosphere and widespread system of flowing rivers and north polar lakes. But located almost a billion miles away from the Sun, everything on Titan is shifted into a completely different—and frigid—level of existence from that found on Earth. With surface temperatures of 300 degrees below zero F, the lakes are filled with liquid methane and what’s life-giving water here is literally solid rock there. Even the rain on Titan falls as oversized drops of ethane.
But even in this extreme cryo-environment it’s possible that life may right now exist…life relying on an entirely different chemistry than what’s possible on our planet.
Recently scientists have identified a molecule on Titan called vinyl cyanide, or acrylonitrile. To Earthly life acrylonitrile is toxic and carcinogenic; luckily for us it isn’t naturally-occurring here. But on Titan it is and apparently in quantity; it’s possible that vinyl cyanide, raining down from Titan’s atmosphere into its vast hydrocarbon lakes, could even help form methane-based cell structures in much the same way phospholipids do here.
The molecule (C2H3CN) has the ability to form membranes and, if found in liquid pools of hydrocarbons on Titan’s surface, it could form a kind of lipid-based cell membrane analog of living organisms on Earth. In other words, this molecule could stew in primordial pools of hydrocarbons and arrange itself in such a way to create a “protocell” that is “stable and flexible in liquid methane,” said Jonathan Lunine (Cornell University) who, in 2015, was a member of the team who modeled vinyl cyanide and found that it might form cell membranes.
Further evidence of life “not as we know it?” Read more on Ian O’Neill’s Astroengine blog here: Vinyl Cyanide Confirmed: Weird Form of Alien Life May Be Possible on Saturn’s Moon Titan and in a Gizmodo article by Maddie Stone here: Potential Building Block of Alien Life Spotted in Titan’s Atmosphere