The Best of Cassini—13 Years in Orbit Around Saturn - The Atlantic

The Atlantic shows The Best of Cassini—13 Years in Orbit Around Saturn

This September, NASA’s Cassini spacecraft will take its final measurements and images as it plunges into Saturn’s atmosphere at 77,000 miles per hour, burning up high above the cloud tops. Launched in 1997, Cassini traveled 2.2 billion miles in seven years to reach Saturn and enter orbit. Over the past 13 years, Cassini’s instruments have returned countless priceless scientific observations and hundreds of thousands of images of the Saturnian system—its atmosphere, its 60+ moons, its vast rings, and much more. Gathered here are 40 of the most amazing images sent to us from Cassini, as we prepare for this epic mission to come to an end in just a few months.

Space Stuff

Universe explains SpaceX Just Re-Used a Rocket. Why This Changes Everything ""

Hubble Takes Advantage of Opposition To Snap Jupiter

On April, 7th, 2017, Jupiter will come into opposition with Earth. This means that Earth and Jupiter will be at points in their orbit where the Sun, Earth and Jupiter will all line up. Not only will this mean that Jupiter will be making its closest approach to Earth – reaching a distance of about 670 million km (416 million mi) – but the hemisphere that faces towards us will be fully illuminated by the Sun.

Juno Sees Overlapping Colliding Clouds on Jupiter

The Juno mission has made some remarkable finds since it reached Jupiter in July of 2016. During the many orbits it has made around Jupiter’s poles – which occur every 53 days – some stunning imagery has resulted. Not only have these pictures revealed things about Jupiter’s atmosphere, they have also been an opportunity for the public to participate in the exploration of this giant planet.

New Up-Close Image of Jupiter's Stormy Clouds is Mind-Blowing

The Verge on Astronauts Scott and Mark Kelly on NASA’s twin experiment and the future of space travel

Mark and Scott Kelly are the only twins that have ever traveled to space — and their experience will be invaluable if we want to get to Mars one day.

Between 2015 and 2016, Scott spent 340 days on the International Space Station, while his genetically identical twin Mark stayed on Earth to function as a control subject. Before, during, and after Scott’s trip, the brothers have been giving NASA numerous biological samples — blood, saliva, poop, you name it. By comparing Scott’s samples with Mark’s, NASA is trying to understand what long-term space travel does to our bodies.

Some preliminary findings have already come out. One study showed that Scott’s DNA changed while he was in space: his telomeres — the protective caps on the end of DNA strands — were unexpectedly longer than Mark’s. (Telomere length can affect aging and age-associated diseases.) Another study showed that there were major fluctuations in Scott’s gut bacteria while he lived in zero-g compared to his twin.

Astronomers just turned on a planet-size telescope to take a picture of a black hole

Vox has a nice piece with some good videos describing how Astronomers just turned on a planet-size telescope to take a picture of a black hole .

Because Sagittarius A is so small, and surrounded by so much occluding material, it’s going to take a huge telescope to see it. According to Nature, it would take a telescope 1,000 times more powerful than Hubble to get enough resolution to see it.

So how does the Event Horizon Telescope solve this problem? Conventional optical telescopes use bigger and bigger mirrors to see objects smaller and farther away in the universe. The Event Horizon Telescope is doing something similar: It’s creating a virtual telescope the size of the entire Earth.

The Event Horizon team is connecting radio telescopes at eight locations across the world — as far-flung as Hawaii and the South Pole — and instructing them all to look toward Sagittarius A for a few days. The network is the result of an international collaboration of 14 research institutions across the world.

Science Articles

At first I misunderstood this Universe Today headline, Curiosity Captures Gravity Wave Shaped Clouds On Mars, to be about gravitational waves, but it's a more normal phenomenon they're seeing in studying Martian clouds from Curiosity. But I loved this line in the article:

But as Moore explained in an interview with Science Magazine, seeing an Earth-like phenomenon on Mars is consistent with what we’ve seen so far from Mars. ‘The Martian environment is the exotic wrapped in the familiar,’ he said. ‘The sunsets are blue, the dust devils enormous, the snowfall more like diamond dust, and the clouds are thinner than what we see on the Earth.’"

Universe Today also reported, Large Hadron Collider Discovers 5 New Gluelike Particles

According to the research paper, which appeared in arXiv on March 14th, 2017, the particles that were detected were excited states of what is known as a “Omega-c-zero” baryon. Like other particles of its kind, the Omega-c-zero is made up of three quarks – two of which are “strange” while the third is a “charm” quark. The existence of this baryon was confirmed in 1994. Since then, researchers at CERN have sought to determine if there were heavier versions.

And now, thanks to the LHCb experiment, it appears that they have found them. The key was to examine the trajectories and the energy left in the detector by particles in their final configuration and trace them back to their original state. Basically, Omega-c-zero particles decay via the strong force into another type of baryon (Xi-c-plus) and then via the weak force into protons, kaons, and pions.

From this, the researchers were able to determine that what they were seeing were Omega-c-zero particles at different energy states (i.e. of different sizes and masses). Expressed in megaelectronvolts (MeV), these particles have masses of 3000, 3050, 3066, 3090 and 3119 MeV, respectively. This discovery was rather unique, since it involved the detection of five higher energy states of a particle at the same time.

Extraterrestrial Origin Of Fast Radio Burst Phenomenon Confirmed:

Fast Radio Bursts (FRBs) have puzzled astronomers since they were first detected in 2007. These mysterious milliseconds-long blasts of radio waves appear to be coming from long distances, and have been attributed to various things such as alien signals or extraterrestrial propulsion systems, and more ‘mundane’ objects such as extragalactic neutron stars. Some scientists even suggested they were some type of ‘local’ source, such as atmospheric phenomena on Earth, tricking astronomers about their possible distant origins.

So far, less than two dozen FRBs have been detected in a decade. But now researchers from the Australian National University and Swinburne University of Technology have detected three of these mystery bursts in just six months using the interferometry capabilities of the Molonglo Observatory Synthesis Telescope (MOST) in Canberra, Australia. In doing so, they were able to confirm that these FRBs really do come from outer space.

The Butterfly Nebula from Hubble

Yesterday's Astronomy Picture of the Day is the my new desktop wallpaper, The Butterfly Nebula from Hubble

"Explanation: The bright clusters and nebulae of planet Earth's night sky are often named for flowers or insects. Though its wingspan covers over 3 light-years, NGC 6302 is no exception. With an estimated surface temperature of about 250,000 degrees C, the dying central star of this particular planetary nebula has become exceptionally hot, shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust. This sharp close-up of the dying star's nebula was recorded by the Hubble Space Telescope and is presented here in reprocessed colors. Cutting across a bright cavity of ionized gas, the dust torus surrounding the central star is near the center of this view, almost edge-on to the line-of-sight. Molecular hydrogen has been detected in the hot star's dusty cosmic shroud. NGC 6302 lies about 4,000 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius)."

The Best Image of Saturn's Moon Daphnis Ever Taken

Phil Plait on The Best Image of Saturn's Moon Daphnis Ever Taken. And It's a Stunner.

That’s the highest-resolution image of Daphnis ever taken; for scale, the flying-saucer-shaped moon is about 8 x 8 x 6 km in size. Measured from sea level, Mount Everest is roughly the same size. You can see some structure to Daphnis; there’s a ridge around its equator that’s probably due to ring particles that have piled up there, and a second ridge at higher latitude. The soft appearance to the moon is probably due to the accumulation of small grains of ice from the rings that have coated it, filling in the craters and other features.

That gap in the rings is real. It’s called the Keeler Gap, and it’s about 30-40 km wide. The width of the gap appears foreshortened because Cassini was just above the ring plane when it took the shot; it’s actually several times wider than the moon is long.

But, oh, those ripples! That, my friends, is the result of gravity. It’s a complicated and intricate dance between moon and rings, but it’s worth learning the moves."

The Elements of Life Mapped Across the Milky Way

The Sloan Digital Sky Survey have mapped the elements of life across the Milky Way

‘For the first time, we can now study the distribution of elements across our Galaxy,’ says Sten Hasselquist of New Mexico State University. ‘The elements we measure include the atoms that make up 97% of the mass of the human body.’

The new results come from a catalog of more than 150,000 stars; for each star, it includes the amount of each of almost two dozen chemical elements. The new catalog includes all of the so-called ‘CHNOPS elements’ – carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur – known to be the building blocks of all life on Earth. This is the first time that measurements of all of the CHNOPS elements have been made for such a large number of stars.

While humans are 65% oxygen by mass, oxygen makes up less than 1% of the mass of all of elements in space. Stars are mostly hydrogen, but small amounts of heavier elements such as oxygen can be detected in the spectra of stars. With these new results, APOGEE has found more of these heavier elements in the inner Galaxy. Stars in the inner galaxy are also older, so this means more of the elements of life were synthesized earlier in the inner parts of the Galaxy than in the outer parts.

While it’s fun speculate what impact the inner Galaxy’s composition might have on where life pops up, we are much better at understanding the formation of stars in our Galaxy. Because the processes producing each element occur in specific types of stars and proceed at different rates, they leave specific signatures in the chemical abundance patterns measured by SDSS/APOGEE. This means that SDSS/APOGEE’s new elemental abundance catalog provides data to compare with the predictions made by models of galaxy formation.

Also they’ve updated Origin of the Elements in the Solar System.

Cassini: Mission to Saturn: Saturn's Hexagon in Motion

Cassini: Mission to Saturn: Saturn’s Hexagon in Motion

The differences in this version of the movie, in which different wavelengths of light from ultraviolet to visible to infrared have been assigned colors, show a distinct contrast between the types of atmospheric particles inside and outside the hexagon. Inside the hexagon there are fewer large haze particles and a concentration of small haze particles, while outside the hexagon, the opposite is true. The jet stream that makes up the hexagon seems to act like a barrier, which results in something like the ‘ozone hole’ in the Antarctic.

This movie shows a view from directly over the north pole, keeping up with the rotation of the planet so that all the motion seen on the screen is the motion of the hexagonal jet stream or the storms inside of it, without any added motion from the spinning of the planet itself. The original images were re-projected to show this polar view.

The eight frames of the movie were captured over 10 hours on Dec.10, 2012. Each of the eight frames consists of 16 map-projected images (four per color filter, and four filters per frame) so the movie combines data from 128 images total."

Princeton Team Directly Observes Planets Around Nearby Stars

Universe Today reports Princeton Team Directly Observes Planets Around Nearby Stars

CHARIS allows astronomers to isolate light reflecting from planets. That’s difficult to do, since they are so much dimmer than the stars they orbit. CHARIS is able to isolate the reflective light from planets larger than Jupiter. Then astronomers can analyze that light to learn about the planet’s age, atmospheric composition, and its size."

The spectrograph sits inside a 500 lb case that measures 30x30x12. Inside that case, it’s kept at –223.15 Celsius (50 Kelvin, –369 F.) The CHARIS instrument has nine mirrors, five filters, two prism assemblies and a microlens array. The microlens array is a special optical device with an array of tiny lenses etched into its surface.

CHARIS is designed to capture the light from distant exoplanets, so its field of view is tiny. It’s only 2 arc-seconds, which is a tiny patch of sky. For reference, the full Moon is about 1,800 arc-seconds. But it can take images across a wide band of light wavelengths. The fact that it captures such a wide band of light is what allows such detailed analysis of anything it’s pointed at.

Hubble Finds 10 Times More Galaxies Than Thought | NASA

NASA reports Hubble Finds 10 Times More Galaxies Than Thought

In analyzing the data, a team led by Christopher Conselice of the University of Nottingham, U.K., found that 10 times as many galaxies were packed into a given volume of space in the early universe than found today. Most of these galaxies were relatively small and faint, with masses similar to those of the satellite galaxies surrounding the Milky Way. As they merged to form larger galaxies the population density of galaxies in space dwindled. This means that galaxies are not evenly distributed throughout the universe's history, the research team reports in a paper to be published in The Astrophysical Journal.

'These results are powerful evidence that a significant galaxy evolution has taken place throughout the universe's history, which dramatically reduced the number of galaxies through mergers between them - thus reducing their total number. This gives us a verification of the so-called top-down formation of structure in the universe,' explained Conselice.

The decreasing number of galaxies as time progresses also contributes to the solution for Olbers' paradox (first formulated in the early 1800s by German astronomer Heinrich Wilhelm Olbers): Why is the sky dark at night if the universe contains an infinity of stars? The team came to the conclusion that indeed there actually is such an abundance of galaxies that, in principle, every patch in the sky contains part of a galaxy.

However, starlight from the galaxies is invisible to the human eye and most modern telescopes due to other known factors that reduce visible and ultraviolet light in the universe. Those factors are the reddening of light due to the expansion of space, the universe's dynamic nature, and the absorption of light by intergalactic dust and gas. All combined, this keeps the night sky dark to our vision.

Images From Offworld

Images From Offworld are just stunning, go look at them all.

Robotic probes launched by NASA, the European Space Agency (ESA), and others are gathering information all across the solar system. We currently have spacecraft in orbit around the Sun, Venus, Earth, Mars, Ceres, a comet, Jupiter, and Saturn; two operational rovers on Mars; and a recent close flyby of Pluto. Astronauts aboard the International Space Station are still performing experiments in low Earth orbit and sending back amazing photos. With all these eyes in the sky, I’d once again like to put together a recent photo album of our solar system—a set of family portraits—as seen by our astronauts and mechanical emissaries. This time, we have a photo of a long-lost lander found on the surface of a comet, new images of Jupiter’s polar regions, color photos from the surface of Mars, a double eclipse of the Sun, and, of course, lovely images of our home, planet Earth.

First look at Jupiter’s north pole—bluer and “hardly recognizable”

Ars Technica reported First look at Jupiter’s north pole—bluer and “hardly recognizable”

This week, scientists got their first look at images and data from the Juno spacecraft's initial flyby of Jupiter's polar regions, and they were thrilled to find an entirely different world than the familiar one which exists around the equator.

'It looks like nothing we have seen or imagined before,' said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. 'It's bluer in color up there than other parts of the planet, and there are a lot of storms. There is no sign of the latitudinal bands or zone and belts that we are used to—this image is hardly recognizable as Jupiter. We're seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features.'

Get Ready for the 2016 Perseids

Universe Today says Get Ready for the 2016 Perseids "The 2016 Perseids present a few challenges, though persistent observers should still see a descent show. The Perseids are typically active from July 17th to August 24th, with the peak arriving this year right around 13:00 to 15:30 Universal Time on Friday, August 12th. This will place the radiant for the Perseids high in the sky after local midnight for observers in the northern Pacific, though observers worldwide should be vigilant over the next week. Meteor showers don’t read predictions and prognostications, and an arrival of the peak just a few hours early would place North America in the cross-hairs this coming Friday. The Perseids typically produce an average Zenithal Hourly Rate of 60-200 per hour, and the International Meteor Organization predicts a ZHR of 150 for 2016."

So for me, I'll be out after midnight Thursday night.

Juno Reaches Jupiter

From July 4th, NASA's Juno spacecraft is now in orbit around Jupiter. "NASA’s Juno spacecraft has successfully entered Jupiter’s orbit, bringing it closer to the planet than any probe has come so far. The vehicle reached the gas giant’s north pole this evening, and NASA received confirmation that the vehicle had turned on its main engine at 11:18PM ET. The engine burned for 35 minutes, helping to slow the spacecraft down enough so that it was captured by Jupiter’s gravitational pull. NASA confirmed that the burn was successful at around 11:53PM ET and that Juno was in its intended 53-day orbit."

But now, Juno is in a highly elliptical orbit around Jupiter that takes 53 days to complete. For most of that orbit, the spacecraft will be far out from Jupiter, avoiding its intense radiation belts and debris field. But at the end of the 53-day cycle, Juno will swing back close to the planet again. During this close pass, the vehicle will first fly over the north pole and then swoop in close over Jupiter's equator — squeezing in between the radiation belts and the planet's surface. Juno then swings back out into space over the planet's south pole.

This whole sequence of events, known as the Perijove pass, will take just a few hours to complete. But it's during this time that Juno will conduct the most science over Jupiter. The spacecraft's onboard instruments will be measuring the amount of water in Jupiter's atmosphere, as well as the planet's gravity and magnetic field. These measurements will help NASA figure out if Jupiter has a dense core underneath its surface. All of these details can be used to piece together exactly how and when Jupiter formed more than 4 billion years ago.

The two big close to Jupiter swings are scheduled for Aug 27th and Oct 19th.

Are has more, After 1.7 billion miles Juno nails its Jupiter orbit to within tens of miles.

In reality, NASA also now sentenced its $1.1 billion (~£850M) spacecraft to die. Mission managers hope to get 37 orbits out of Juno over the next 20 months before radiation slowly breaks down its electronics and propulsion system. Even though a 1cm-thick wall of titanium encases the spacecraft’s electronics to provide some protection, a few of its nine instruments may begin to fail in as few as eight or 10 orbits. Before the spacecraft fails entirely engineers will place Juno into a slowly degrading orbit that will eventually force it to plunge into the planet. This is so that none of its potentially life bearing moons, such as Europa, might be contaminated.

In other NASA news, The Verge reports Hubble is capturing stunning photos of Jupiter’s giant auroras

The Surface of Pluto

"This is the most detailed view of Pluto’s terrain you’ll see for a very long time. This mosaic strip – extending across the hemisphere that faced the New Horizons spacecraft as it flew past Pluto on July 14, 2015 – now includes all of the highest-resolution images taken by the NASA probe. With a resolution of about 260 feet (80 meters) per pixel, the mosaic affords New Horizons scientists and the public the best opportunity to examine the fine details of the various types of terrain on Pluto, and determine the processes that formed and shaped them. "

Possible Link Between Primordial Black Holes and Dark Matter

NASA reports a Possible Link Between Primordial Black Holes and Dark Matter.

Dark matter is a mysterious substance composing most of the material universe, now widely thought to be some form of massive exotic particle. An intriguing alternative view is that dark matter is made of black holes formed during the first second of our universe's existence, known as primordial black holes. Now a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, suggests that this interpretation aligns with our knowledge of cosmic infrared and X-ray background glows and may explain the unexpectedly high masses of merging black holes detected last year.

'This study is an effort to bring together a broad set of ideas and observations to test how well they fit, and the fit is surprisingly good,' said Alexander Kashlinsky, an astrophysicist at NASA Goddard. 'If this is correct, then all galaxies, including our own, are embedded within a vast sphere of black holes each about 30 times the sun's mass.'

The Bubble Nebula

Today's APOD is crazy amazing, NGC 7635: The Bubble Nebula "Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape. Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. Although it looks delicate, the 7 light-year diameter bubble offers evidence of violent processes at work. Above and left of the Bubble's center is a hot, O-type star, several hundred thousand times more luminous and around 45 times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The intriguing Bubble Nebula and associated cloud complex lie a mere 7,100 light-years away toward the boastful constellation Cassiopeia. This sharp, tantalizing view of the cosmic bubble is a composite of Hubble Space Telescope image data from 2016, released to celebrate the 26th anniversary of Hubble's launch."

More versions here.

Supermassive Black Holes In Distant Galaxies Are Mysteriously Aligned

Universe Today reports Supermassive Black Holes In Distant Galaxies Are Mysteriously Aligned

In 1974, astronomers detected a massive source of radio wave emissions coming from the center of our galaxy. Within a few decades time, it was concluded that the radio wave source corresponded to a particularly large, spinning black hole. Known as Sagittarius A, this particular black hole is so large that only the designation ‘supermassive’ would do. Since its discovery, astronomers have come to conclude that supermassive black holes (SMBHs) lie at the center of almost all of the known massive galaxies.

But thanks to a recent radio imaging by a team of researchers from the University of Cape Town and University of the Western Cape, in South Africa, it has been further determined that in a region of the distant universe, the SMBHs are all spinning out radio jets in the same direction. This finding, which shows an alignment of the jets of galaxies over a large volume of space, is the first of its kind, and could tell us much about the early Universe.

The Heartbeat of an Exploded Star

Phil Plait writes about Video shows gas cloud expanding over time. "A thousand years ago—in July 1054, to be somewhat more precise—the light from a cosmic catastrophe reached Earth. A massive star, probably 20 or more times the heft of the Sun, exploded. This titanic event was vast almost beyond human grasp: It released as much energy in a few weeks as the Sun will over its entire 10-billion-year lifetime."

"Amazing as the image is, there’s another, subtler aspect of it that will cook your brain. That debris you see is still expanding, and quite rapidly. Because the Crab is tremendously far away—6,500 light-years or so—any motion is shrunk down to near invisibility. But we’ve been observing it for decades, which is a pretty long baseline. That means that if you compare an earlier image to a later one, you can actually see the physical expansion of the supernova explosion."

M1: The Crab Nebula Supernova Remnant (animation) from Adam Block on Vimeo."This animation shows the expansion of the Crab Nebula between the years of 1999 and 2012. The 1999 picture was taken by ESO using the VLT. The more recent picture was taken at the Mount Lemmon SkyCenter using the 0.8m Schulman Telescope. "

Forget Starships: New Proposal Would Use 'Starchips' To Visit Alpha Centauri

NPR reports Forget Starships: New Proposal Would Use 'Starchips' To Visit Alpha Centauri

Physicist Stephen Hawking and billionaire Yuri Milner have a vision of interstellar exploration — taking place over the course of not thousands of years, but decades.

Together with a team of scientists, they suggest that within a generation, humans could send a probe to Alpha Centauri — more than 4.3 light-years away, or 25 trillion miles — on a trip that would take just over two decades. That's 1,000 times faster than the current fastest spacecraft, the scientists say.

They're thinking big — by thinking very small.

Instead of sending a car-size or piano-size probe, the 'Breakthrough Starshot' team is proposing a postage-stamp-size spacecraft — a 'starchip.' The project, announced by Hawking and Milner on Tuesday, would engineer a method for such a nanocraft to be propelled through space by a sail, pushed by a powerful laser aimed from Earth."

More details here, including a llist of challenges.