Universe Today

April 12, 2018 by Fraser Cain

Living Underground on Other Worlds. Exploring Lava Tubes

Pangaea-X arrives at the entrance to La Cueva de los Verdes lava tube. . Credit and Copyright: ESA–Robbie Shone

The Moon and Mars will probably be the first places in the Solar System that humanity will try to live after leaving the safety and security of Earth. But those worlds are still incredibly harsh environments, with no protection from radiation, little to no atmosphere, and extreme temperatures.

Living on those worlds is going to be hard, it’s going to be dangerous. Fortunately, there are a few pockets on those worlds that’ll make it a tiny little bit easier to get a foothold in the Solar System: lava tubes.

I’m going to show you some really cool photographs now. First, let’s start with images of the Moon taken by NASA’s Lunar Reconnaissance Orbiter.

Images of open lava tubes on the Moon. Image credit: NASA/LRO

Those dark blobs in the photo are actually open skylights, the collapsed roofs of lava tubes on the Moon. They just look like dark areas because you can’t see the bottom. How cool is that?

And now, here are similar features on the surface of Mars. Here are several examples of cave skylights across the Red Planet.

Images of cave openings on a Martian volcano. Credit: NASA/JPL-Caltech/ASU/USGS

And I want to show you a really special one. Check out this photo, where you can see the cave opening, how the Martian sand is flowing down into the skylight. You can even see it piling up on the cave floor. There’s no question, this is a cavern on Mars with opening to the surface.

Detailed image of a skylight. Credit: NASA/JPL/University of Arizona

Want to live on the Moon or Mars? You’re looking at your future home.

Lava tubes are a common here on Earth, and you can find them wherever there’s been volcanic activity. During an eruption, lava gets flowing downhill through a channel. The surface cools and crusts over, but the lava keeps on flowing, like an underground river of molten rock.

In the right conditions, the lava can keep flowing, and empty out the channel completely, leaving behind a natural tunnel that can be dozens of kilometers long. The tubes can be wide, from a single meter to up to 15 meters wide. Definitely big enough to live inside.

Exploring lava tubes in the Canary Islands. Credit: ESA-L.Ricci

Both the Moon and Mars had periods of volcanism. The biggest volcano in the Solar System, Olympus Mons on Mars, is an enormous shield volcano with endless lava fields surrounding it.

The SETI Institute recently announced that they had identified a series of small pits in a crater near the Moon’s northern pole. They found them by analyzing images taken by NASA’s Lunar Reconnaissance Orbiter.

They look like skylights, and match similar features on Mars, where there is no crater rim, and just a shadowed dark feature. Further evidence is that they lie along lunar sinuous rilles, those ancient lava rivers with collapses features in a row.

At this point, there have been about 200 of these features discovered on the Moon so far, and more discovered on Mars too.

In addition to the skylights discovered by spacecraft, planetary scientists have uncovered vast pit chains on Mars, which could be collapsed lava tubes. With the amount of volcanism that occured on Mars over billions of years, there should be many features worth exploring.

Pit Chains in Tharsis. Credit: ESA/DLR/FU Berlin (G. Neukum)

Because of the lower gravity on the Moon and Mars, lava tubes should be much more extreme. On Mars, there could be lava tubes that measure hundreds of meters across, and hundreds of kilometers long. On the Moon, lava tubes could be kilometers across. Big enough to hide a city inside.

Future Moon and Mars colonists will already be facing a life underground, to hide from the surface radiation, micrometeorite bombardment, extreme temperatures and to create a usable atmosphere. These natural tunnels will save them the hard work of needing to dig the tunnel.

The natural roofs on these caverns are thought to be 10 meters or more thick, with one site estimated to have a roof that’s 45-90 meters thick. This would be more than enough to protect against solar radiation and galactic cosmic radiation.

While the surface of the Moon varies in temperature from -180 C to +100 C, the interior of a lava tube would remain a constant chilly -20 C. This would be easy enough to keep warmed up, once it was sealed off and pressurized with a breathable atmosphere.

As we’ve mentioned time and time again, the lunar dust on the Moon is dangerous stuff, irritating eyes, nasal passages and lungs. Lunar colonists would want to minimize their exposure to it at all costs. By sealing off the interior of the lava tube, they could prevent further dust from getting in. In fact, the dust is also electrically charged, and could be a hazard to electronics.

In terms of resources, the Moon has plenty. There’s aluminum everywhere in the regolith, as well as iron and titanium. But the most valuable one for humans, water, could be down there too. In the eternally shadowed craters, there could be large deposits of water collected down below that colonists could harvest.

There’s another advantage, the lava tubes on Mars could be the best places to search for life on the Red Planet. The natural protection would also keep Martian bacteria less exposed to the harsh conditions of the surface.

Future explorers could be protected inside the lava tubes at the same time that they’re in the ideal place to search for life on Mars. That’s convenient.

Of course NASA and the European Space Agency have considered human and robotic missions that could travel to the Moon or Mars and explore the interiors of lava tubes.

In 2011, a group of researchers proposed a mission design for a combined lander-rover that would map out a skylight on the Moon in incredible detail. It’s known as the Marius Hills Hole, and measures about 65 meters across.

First, the lander would descend down to the surface of the Moon near the hole, using a pulsed laser called LIDAR to map out a 50-meter region around the landing site, looking for hazards.

The spacecraft would then choose a landing site and deploy a rover that would scan the region around the skylight in extreme detail, peeking down into the lava tube when the light is right.

Following that, would come the missions to actually explore down in the tunnels. Remember how big they are, potentially hundreds of meters and even kilometers across.

You can imagine various robotic rovers and landers, but one of my favorite ideas is a snake robot developed by SINTEF in Norway. The robot uses hydraulics to move segments of its body, allowing it to move like a real snake. It could climb stairs, navigate up and down slopes, go around corners, and be able to handle the unpredictable terrain of the floor of a lavatube.

After the robots come the humans. The tricky part is getting from the surface down to the tunnel floor. Mission planners have proposed traditional rappelling and even astronauts with jetpacks who would lower themselves down into the tunnel to explore around.

The first astronauts would descend down to the floor of the lava tube bringing quadruped pack mule robots that would be able to navigate the rough terrain of the tunnel floor. Once inside, they’d set up a communications link at the crater opening, and then deploy a pressurized tent as a temporary habitat.

The astronauts would be free to travel several kilometers into the lava tube, mapping the interior, and taking samples. They could set up their tent at different points, allowing a much deeper exploration.

Of course, then hostile cave aliens would pick them off one by one, and the only way we’d know about the mission is from a series of found footage and computer logs. But I digress.

The European Space Agency has been developing tools to measure the interior of caves here on Earth, to develop the technology that could be used to explore other worlds. You’re looking at a 3D image of the interior of a cave network in Spain.

Volcanic wormhole. Copyright: Vigea – Tommaso Santagata

A team of researchers, including a European astronaut, used backpack-based cameras and LIDAR instruments to map out the cave to a resolution of just a few centimeters. They also tested out handheld tools to examine the cave walls, doing the same kinds of experiments future astronauts might do.

The long term goal, of course, is to set up some kind of long term colony inside lava tubes on the Moon or Mars.

What started as a temporary hiding place from the brutal environment of the Moon and Mars would become the base of operations for a future habitat and eventually the beginnings of a scientific outpost or even a full colony.

There’s no question that lava tubes are going to be one of the top priorities when we return to the Moon, and when the first astronaut sets foot on Mars. And with all the new missions in the works, from both NASA, SpaceX, the Europeans and even the Chinese, it looks like those days aren’t too far off now.

April 12, 2018 by Bob King

See The Finest Sights Before You Die With “Wonders of the Night Sky”

Framed by stars reflected by water, a kayaker leans back to take in the grandeur of the night sky. The photo appears in my new book in the chapter titled “Stars on Water.” Credit: Bob King

After months parked in front of a computer, I’m thrilled to announce the publication of my new book. The full title is — get ready for this — Wonders of the Night Sky You Must See Before You Die: The Guide to Extraordinary Curiosities of Our Universe. In a nutshell, it’s a bucket list of cosmic things I think everyone should see sometime in their life.

I couldn’t live without the sky. The concerns of Earth absorb so much of our lives that the sky provides an essential relief valve. It’s a cosmos-sized wilderness that invites both deep exploration and reflection. Galileo would kill to come back for one more clear night if he could.

Cover of Wonders of the Night Sky. 57 different sights are featured.

To me, the stars are irresistible, but my sense is that many people don’t look up as much as they’d like. We forget. Get busy. Bad weather intervenes. So I thought hard about the essential “must-sees” for any watcher of the skies. Some are obvious, like a total solar eclipse or Saturn through a telescope, but others are just as interesting — if sometimes off the beaten path.

For instance, we always hear about asteroids in the news. What does a real one look like from your own backyard? I give directions and a map for seeing the brightest of them, Vesta. And if you’ve ever looked up at the Big Dipper and wondered how to find the rest of the Great Bear, I’ll get you there. I love red stars, so you’re going to find out where the reddest one resides and how to see it yourself. There’s also a lunar Top 10 for small telescope users and chapters on the awesome Cygnus Star Cloud and how to see a supernova.

You can see most of the sky wonders described in the book from the northern hemisphere, but I included several essential southern sights like the Southern Cross.

The 57 different sights are a mix of naked-eye objects plus ones you’ll need an ordinary pair of binoculars or small telescope to see. At the end of each chapter, I provide directions on how and when to find each wonder. Because we live in an online world with so many wonderful tools available for skywatchers, I make extensive use of mobile phone apps that allow anyone to stay in touch with nearly every aspect of the night sky.

For the things that need a telescope, the resources section has suggestions and websites where you can purchase a nice but inexpensive instrument. Of course, you may not want to buy a telescope. That’s OK. I’m certain you’ll still enjoy reading about each of these amazing sights to learn more about what’s been up there all your life.

Northern spectacles like the Perseus Double Cluster can’t be missed.

While most of the nighttime sights are visible from your home or a suitable dark sky site, you’ll have to travel to see others. Who doesn’t like to get out of the house once in a while? If you travel north or south, new places mean new stars and constellations. I included chapters on choice southern treats like Alpha Centauri, the Southern Cross and the Magellanic Clouds, the closest and brightest galaxies to our own Milky Way.

One of my favorite parts of the book is the epilogue, where I share a lesson my dog taught me about the present moment and cosmic time. I like to joke that if nothing else, the ending’s worth the price of the book.

The author with his 10-inch Dobsonian reflector. Credit: Linda Hanson

The staff at Page Street Publishing did a wonderful job with the layout and design, so “Wonders” is beautiful to look at. Everyone who’s flipped through it likes the feel, and several people have even commented on how good it smells! And for those who understandably complained that the typeface in my first book, Night Sky with the Naked Eye, made it difficult to read, I’ve got good news for you. The new book’s type is bigger and easy on the eyes.

“Wonders” is 224 pages long, printed in full color and the same size as my previous book. Unlike the few but longer chapters of the first book, the new one has many shorter chapters, and you can dip in anywhere. I think you’ll love it.

The publication date is April 24, but you can pre-order it right now at Amazon, BN and Indiebound. I want to thank Fraser Cain here at Universe Today for letting me tell you a little about my book, and I look forward to the opportunity to share my night-sky favorites with all of you.

April 12, 2018 by Matt Williams

Dense Star Clusters Could be the Places Where Black Hole Mergers are Common

A snapshot of a simulation showing a binary black hole formed in the center of a dense star cluster. Credit: Northwestern Visualization/Carl Rodriguez

In February of 2016, scientists working for the Laser Interferometer Gravitational-Wave Observatory (LIGO) made history when they announced the first-ever detection of gravitational waves. Not only did this discovery confirm a century-old prediction made by Einstein’s Theory of General Relativity, it also confirmed the existence of stellar binary black holes – which merged to produce the signal in the first place.

And now, an international team led by MIT astrophysicist Carl Rodriguez has produced a study that suggests that black holes may merge multiple times. According to their study, these “second-generation mergers” likely occur within globular clusters, the large and compact star clusters that typically orbit at the edges of galaxies – and which are densely-packed with hundreds of thousands to millions of stars.

The study, titled “Post-Newtonian Dynamics in Dense Star Clusters: Highly Eccentric, Highly Spinning, and Repeated Binary Black Hole Mergers“, recently appeared in the Physical Review Letters. The study was led by Carl Rodriguez, a Pappalardo fellow in MIT’s Department of Physics and the Kavli Institute for Astrophysics and Space Research, and included members from the Institute of Space Sciences and the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA).

As Carl Rodriguez explained in a recent MIT press release:

“We think these clusters formed with hundreds to thousands of black holes that rapidly sank down in the center. These kinds of clusters are essentially factories for black hole binaries, where you’ve got so many black holes hanging out in a small region of space that two black holes could merge and produce a more massive black hole. Then that new black hole can find another companion and merge again.”

Globular clusters have been a source of fascination ever since astronomers first observed them in the 17th century. These spherical collections of stars are among the oldest known stars in the Universe, and can be found in most galaxies. Depending on the size and type of galaxy they orbit, the number of clusters varies, with elliptical galaxies hosting tens of thousands while galaxies like the Milky Way have over 150.

For years, Rodriguez has been investigating the behavior of black holes within globular clusters to see if they interact with their stars differently from black holes that occupy less densely-populated regions in space. To test this hypothesis, Rodriguez and his colleagues used the Quest supercomputer at Northwestern University to conduct simulations on 24 stellar clusters.

These clusters ranged in size from 200,000 to 2 million stars and covered a range of different densities and metallic compositions. The simulations modeled the evolution of individual stars within these clusters over the course of 12 billion years. This span of time was enough to follow these stars as they interacted with each other, and eventually formed black holes.

In February 2016, LIGO detected gravity waves for the first time. As this artist's illustration depicts, the gravitational waves were created by merging black holes. The third detection just announced was also created when two black holes merged. Credit: LIGO/A. Simonnet. — *Artist’s impression of merging binary black holes. Credit: LIGO/A. Simonnet.*

The simulations also modeled the evolution and trajectories of black holes once they formed. As Rodriguez explained:

“The neat thing is, because black holes are the most massive objects in these clusters, they sink to the center, where you get a high enough density of black holes to form binaries. Binary black holes are basically like giant targets hanging out in the cluster, and as you throw other black holes or stars at them, they undergo these crazy chaotic encounters.”

Whereas previous simulations were based on Newton’s physics, the team decided to add Einstein’s relativistic effects into their simulations of globular clusters. This was due to the fact that gravitational waves were not predicted by Newton’s theories, but by Einstein’s Theory of General Relativity. As Rodriguez indicated, this allowed for them to see how gravitational waves played a role:

“What people had done in the past was to treat this as a purely Newtonian problem. Newton’s theory of gravity works in 99.9 percent of all cases. The few cases in which it doesn’t work might be when you have two black holes whizzing by each other very closely, which normally doesn’t happen in most galaxies… In Einstein’s theory of general relativity, where I can emit gravitational waves, then when one black hole passes near another, it can actually emit a tiny pulse of gravitational waves. This can subtract enough energy from the system that the two black holes actually become bound, and then they will rapidly merge.”

*Artist’s conception shows two merging black holes similar to those detected by LIGO on January 4th, 2017. Credit: LIGO/Caltech*

What they observed was that inside the stellar clusters, black holes merge with each other to create new black holes. In previous simulations, Newtonian gravity predicted that most binary black holes would be kicked out of the cluster before they could merge. But by taking relativistic effects into account, Rodriguez and his team found that nearly half of the binary black holes merged to form more massive ones.

As Rodriguez explained, the difference between those that merged and those that were kicked out came down to spin:

“If the two black holes are spinning when they merge, the black hole they create will emit gravitational waves in a single preferred direction, like a rocket, creating a new black hole that can shoot out as fast as 5,000 kilometers per second — so, insanely fast. It only takes a kick of maybe a few tens to a hundred kilometers per second to escape one of these clusters.”

This raised another interesting fact about previous simulations, where astronomers believed that the product of any black hole merger would be kicked out of the cluster since most black holes are assumed to be rapidly spinning. However, the gravity wave measurements recently obtained from LIGO appear to contradict this, which has only detected the mergers of binary black holes with low spins.

*Artist’s impression of two merging black holes. Credit: Bohn, Throwe, Hébert, Henriksson, Bunandar, Taylor, Scheel/SXS*

This assumption, however, seems to contradict the measurements from LIGO, which has so far only detected binary black holes with low spins. To test the implications of this, Rodriguez and his colleagues reduced the spin rates of the black holes in their simulations. What they found was that nearly 20% of the binary black holes from clusters had at least one black hole that ranged from being 50 to 130 solar masses.

Essentially, this indicated that these were “second generation” black holes, since scientists believe that this mass cannot be achieved by a black hole that formed from a single star. Looking ahead, Rodriguez and his team anticipate that if LIGO detects an object with a mass within this range, it is likely the result of black holes merging within dense stellar cluster, rather than from a single star.

“If we wait long enough, then eventually LIGO will see something that could only have come from these star clusters, because it would be bigger than anything you could get from a single star,” Rodriguez says. “My co-authors and I have a bet against a couple people studying binary star formation that within the first 100 LIGO detections, LIGO will detect something within this upper mass gap. I get a nice bottle of wine if that happens to be true.”

The detection of gravitational waves was a historic accomplishment, and one that has enabled astronomers to conduct new and exciting research. Already, scientists are gaining new insight into black holes by studying the byproduct of their mergers. In the coming years, we can expect to learn a great deal more thanks to improve methods and increased cooperation between observatories.

Further Reading: MIT, Physical Review Letters

April 11, 2018 by Matt Williams

Elon Musk Just Shared an Image of the Main Body Tool for Building the BFR. That Thing is F’ing Big!

Artist's impression of the ITS (BFR) conducting a service run to the ISS. Credit: SpaceX

In September of 2016, Elon Musk announced the latest addition to the SpaceX rocket family. Known then as the Interplanetary Transport System (ITS) – now know as the Big Falcon Rocket (BFR) – this massive launch vehicle is central to Musk’s vision of sending astronauts and colonists to Mars someday. Since that time, the space community has eagerly waited for any news on how the preparations for this rocket are going.

Musk further inflamed people’s anticipation by recently announcing that the BFR would be ready to conduct orbital flights by as early as 2020. While admittedly an optimistic deadline, Musk indicated that his company was building the presently building the ship. And according to a recent post on Musk’s Instagram account, a key component (the main body tool) for making the BFR interplanetary spaceship has just been completed.

It is important to note, however, that what is being shown here is not actually a part of the rocket. As Ryan Whitwam of Extreme Tech noted, what we are seeing in the post is a tool “that SpaceX will use to fabricate the rocket from carbon fiber composite materials that are lighter than traditional materials. Flexible resin sheets of carbon fiber will be layered on the tool and then heated to cure them. After heating, you’re left with a solid section of rocket fuselage. It’s essentially a carbon fiber jig.”

https://www.instagram.com/p/BhVk3y3A0yB/?hl=en

Nevertheless, from the size of the tool itself, one gets a pretty clear idea of how large the final rocket will be. SpaceX chose to illustrate the scale of the tool by placing a Tesla next to it for scale. For some additional perspective, consider the cherry Tesla Roadster (driven by Starman) SpaceX launched with the Falcon Heavy‘s maiden flight.

Whereas the payload capsule was barely large enough to house it, this car looks like it could fit inside any rocket turned out by this tool easily, and with plenty of room to spare. And while cars are not exactly the BFR’s intended payload, it is good to know that it will be no slouch in that department!

When completed, the BFR will be the largest and most powerful rocket in the SpaceX rocket family. According to the company’s own specifications, it will measure 106 meters (348 ft) in height and 9 meters (30 ft) in diameter and will be able to deliver a payload of 150,000 kg (330,000 lb) to Low-Earth Orbit (LEO) – almost two and a half times the payload of the Falcon Heavy (63,800 kg; 140,660 lb).

And as Musk indicated during an interview with Jonathon Nolan at the 2018 South by Southwest Conference (SXSW) in Austin, Texas, it will even outpace the rockets that won the Space Race for the US:

“This a very big booster and ship. The liftoff thrust of this would be about twice that of a Saturn V (the rockets that sent the Apollo astronauts to the Moon). So it’s capable of doing 150 metric tons to orbit and be fully reusable. So the expendable payload is about double that number.”

Once completed, Musk hopes to see the BFR performing service missions to Low-Earth Orbit (LEO), the International Space Station, to the Moon, and – of course – to Mars. In addition to sending colonists there as early as the next decade, Musk has also expressed interest in using the BFR to conduct space tourism – flying passengers in luxury accommodations to the Red Planet and back.

In the end, it is clear that Musk and the company he founded for the purpose of reigniting space exploration are determined to make all of this happen. In the coming years, it will be interesting to see how far and how fast they progress.

Further Reading: Instagram, SpaceX, Extreme Tech

April 11, 2018April 11, 2018 by Fraser Cain

Zoom In, and In, and In! on this Amazing Falcon 9 Photo by Brady Kenniston

The zoomed in view of SpaceX Falcon 9. Credit: Brady Kenniston/NASA Spaceflight

On Monday, April 2 the 14th Commercial Resupply Mission to the International Space Station blasted off Cape Canaveral, Florida. It was carrying a Dragon spacecraft filled with cargo for the astronauts on board the station.

The rocket was a re-used Falcon 9 rocket, as was the Dragon capsule; both had sent payloads to ISS before.

To really appreciate that well worn, flight-tested rocket you should take a really really close look at it.

And now you can, thanks to the work of NASA Spaceflight photographer Brady Kenniston. Brady took 25 separate images using a 600 mm lens with a Nikon D500 and then stitched them together in Lightroom. According to Kenniston, If you could print off this picture at a print resolution 300 DPI, it would create a 1/22nd scale rocket that was over 3 meters.

In fact, that’s exactly what he did:

This is great! Thank you! Not sure if you saw this but I did in fact do a 300dpi print that’s 10 feet long and it’s incredible. pic.twitter.com/PnNKPwU6Ej

— Brady Kenniston (@TheFavoritist) April 11, 2018

If you want to explore every nook and cranny of this rocket, head over to an Easyzoom version that Brady uploaded, which allows you to zoom into extreme detail and see every ding, scratch, and scorched paint on the side of the rocket.

And if you want to see more of Brady’s work, check out his photos on NASA Spaceflight and from his personal site. Or follow him on Twitter.

Source: Brady Kenniston/NASA Spaceflight

April 11, 2018May 4, 2018 by Fraser Cain

Weekly Space Hangout: April 11, 2018: Emily Lakdawalla’s “The Design and Engineering of Curiosity: How the Mars Rover Performs Its Job”

Hosts:
Fraser Cain (universetoday.com / @fcain)
Dr. Paul M. Sutter (pmsutter.com / @PaulMattSutter)
Dr. Kimberly Cartier (KimberlyCartier.org / @AstroKimCartier )
Dr. Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg & ChartYourWorld.org)

Special Guests:
This week we are excited to welcome Emily Lakdawalla, Senior Editor and Planetary Evangelist at The Planetary Society, back to the Weekly Space Hangout. On On May 14th, Emily’s new book, The Design and Engineering of Curiosity: How the Mars Rover Performs Its Job, will be released. It in, Emily describes the engineering that went into each instrument and piece of machinery incorporated into Curiosity’s systems. You can learn more about the book and Emily’s planned followup book on her blog here:
http://www.planetary.org/blogs/emily-lakdawalla/2017/0831-book-update.html

Announcements:
If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

We record the Weekly Space Hangout every Wednesday at 5:00 pm Pacific / 8:00 pm Eastern. You can watch us live on Universe Today, or the Weekly Space Hangout YouTube page – Please subscribe!

April 11, 2018 by Susie Murph

Carnival of Space #556

Carnival of Space. Image by Jason Major.

This week’s Carnival of Space is hosted by Brian Wang at his Next Big Future blog.

Click here to read Carnival of Space #556
Continue reading “Carnival of Space #556”

April 11, 2018 by David Dickinson

New Saturn Storm Emerging?

Are you following the planets this season? The planetary action is about to heat up, as Jupiter, Saturn and Mars all head towards fine oppositions over the next few months.

Spying the Storms of Saturn

Astrophotographer Damian Peach raised the alarm on Twitter this past week of a possible bright storm emerging of the planet Saturn. The spot was noticeable even with the naked eye and in the raw video Peach captured, a sure sign that the storm was a biggie.

Though outbursts of clusters of white spots on the surface of Saturn aren’t uncommon, it’s rare to see one emerge at such a high latitude. The storm had faded considerably the next observing session Peach performed on April 5th, though observers should remain vigilant.

Saturn Storm 2 — A storm subsiding? The followup view a few days later on April 5th. Image credit and copyright: Damian Peach.

It’s sad to think: Cassini and our eyes in the outer solar system are no more… and the situation will probably remain this way for some years to come. Juno also wraps up its mission at Jupiter (pending extension) this year, and New Horizons visits its final destination Ultima Thule (neé 2014 MU69) on New Year’s Day 2019, though it’ll likely continue to chronicle its journey through the outer realms of the solar system, much like the Voyager 1, 2 and Pioneer 10, 11 missions, also bound to orbit the galaxy, mute testaments to human civilization. But even though proposals for Europa Clipper, a nuclear-powered quad-copter for Saturn’s moon Titan, and a Uranus and/or Neptune Orbiter are all on the drawing board, the “gap decade” of outer solar system exploration will indeed come to pass and soon.

But dedicated amateur astronomers continue to monitor the outer solar system for changes. This month sees Saturn rising around 1:30 AM local and transiting highest to the south for northern hemisphere observers at 6:00 AM local, just before sunrise. Saturn crosses the constellation Sagittarius in 2018, bottoming out at its most southerly point this year for its 29 year path around the Sun. Saturn currently shines at +0.4 magnitude, extending 40” across (including rings) as it heads towards a fine opposition on June 27th. After opposition, Saturn formally crosses into the dusk sky. The amazing rings are an automatic draw, but last week’s storm admonishes us not to forget to check out the saffron-colored disk of Saturn itself as well. For example, I’ve always wondered: why didn’t we see the hexagon before? It’s right there festooning the northern hemisphere cap, plain as day in modern amateur images… to be sure, we’re in a modern renaissance of planetary astrophotography today, what with image stacking and processing, but surely eagle-eyed observers of yore could’ve easily picked this feature out.

And the view is changing as well, as Saturn’s rings reached a maximum tilt in respect to our line of sight of 27 degrees in 2017, and now head back towards edge-on again in 2025. And be sure to check out Saturn’s retinue of moons, half a dozen of which are easily visible in a telescope at even low power.

Finally, here’s another elemental mystery poised by Saturn related to the current storm, one that Cassini sought to solve in its final days: how fast does Saturn rotate, exactly? The usual rough guesstimate quoted is usually around 10.5 hours, but we’ve yet to pin down this fundamental value with any degree of precession.

One thing’s definitely for sure: we need to go back. In the meantime, we can enjoy the early morning views of the most glorious of the planets in our Solar System.

April 10, 2018 by Bob King

Io Afire With Volcanoes Under Juno’s Gaze

NASA / JPL-Caltech / SwRI / ASI / INAF /JIRAM / Roman Tkachenko

An amazingly active Io, Jupiter’s “pizza moon” shows multiple volcanoes and hot spots in this photo taken with Juno’s infrared camera. Credit: NASA / JPL-Caltech / SwRI / ASI / INAF /JIRAM / Roman Tkachenko

Volcanic activity on Io was discovered by Voyager 1 imaging scientist Linda Morabito. She spotted a little bump on Io’s limb while analyzing a Voyager image and thought at first it was an undiscovered moon. Moments later she realized that wasn’t possible — it would have been seen by earthbound telescopes long ago. Morabito and the Voyager team soon came to realize they were seeing a volcanic plume rising 190 miles (300 km) off the surface of Io. It was the first time in history that an active volcano had been detected beyond the Earth. For a wonderful account of the discovery, click here.

Linda Morabito spotted the puzzling plume off Io’s limb in this photo, taken on March 8, 1979, three days after Voyager 1’s encounter with Jupiter. It really does look like another moon poking out from behind Io. A second plume over the terminator (border between day and night) catches the rays of the rising Sun. Credit: NASA / JPL

Today, we know that Io boasts more than 130 active volcanoes with an estimated 400 total, making it the most volcanically active place in the Solar System. Juno used its Jovian Infrared Aurora Mapper (JIRAM) to take spectacular photographs of Io during Perijove 7 last July, when we were all totally absorbed by close up images of Jupiter’s Great Red Spot.

Io is captured here by NASA’s Galileo spacecraft. Deposits of sulfur dioxide frost appear in white and grey hues while yellowish and brownish hues are probably due to other sulfurous materials. Bright red materials, such as the prominent ring surrounding Pele (lower left), and “black” spots mark areas of recent volcanic activity. Credit: NASA / JPL / University of Arizona

Juno’s Io looks like it’s on fire. Because JIRAM sees in infrared, a form of light we sense as heat, it picked up the signatures of at least 60 hot spots on the little moon on both the sunlight side (right) and the shadowed half. Like all missions to the planets, Juno’s cameras take pictures in black and white through a variety of color filters. The filtered views are later combined later by computers on the ground to create color pictures. Our featured image of Io was created by amateur astronomer and image processor Roman Tkachenko, who stacked raw images from this data set to create the vibrant view.

This map shows thermal emission from erupting volcanoes on Io. The larger the spot, the larger the thermal emission. Credit: NASA/JPL-Caltech/Bear Fight Institute

Io’s hotter than heck with erupting volcano temperatures as high as 2,400° F (1,300° C). Most of its lavas are made of basalt, a common type of volcanic rock found on Earth, but some flows consist of sulfur and sulfur dioxide, which paints the scabby landscape in unique colors.

This five-frame sequence taken by NASA’s New Horizons spacecraft on March 1, 2007 captures the giant plume from Io’s Tvashtar volcano.

Located more than 400 million miles from the Sun, how does a little orb only a hundred miles larger than our Moon get so hot? Europa and Ganymede are partly to blame. They tug on Io, causing it to revolve around Jupiter in an eccentric orbit that alternates between close and far. Jupiter’s powerful gravity tugs harder on the moon when its closest and less so when it’s farther away. The “tug and release”creates friction inside the satellite, heating and melting its interior. Io releases the pent up heat in the form of volcanoes, hot spots and massive lava flows.

Always expect big surprises from small things.

April 10, 2018 by Fraser Cain

Now’s Your Chance to Play Kerbal Space Program for Only $12 US

Kerbal Space Program and others as part of the Humble Monthly Bundle

I’m a huge fan of the Kerbal Space Program. I’m not great at it, but I’m a huge fan. In fact, I’ve said on many occasions that I’ve learned more about orbital mechanics from this game than I have from almost 20 years of space journalism – and I’m not the only one.

It’s one thing to write stories about rockets flying to orbit, and quite another to actually design, launch and then pilot your own vehicle into orbit.

And if you’ve been sitting on the fence, there’s a pretty sweet deal going on right now from Humble Bundle. For $12 USD you can sign up for their Monthly Humble Bundle and get Kerbal Space Program and two other games. And then when the full bundle unlocks you’ll get a handful of additional games. Part of the money goes to worthy charities too.

Normally Kerbal Space Program costs $40ish on Steam, and I’ve seen it in discounts of 40% off, so I’ve never seen it going this cheap.

This isn’t an ad, by the way, Humble Bundle didn’t give me any money. I’ve been a paying customer of the Monthly Bundles since they started up and I’m always find good value and fun games to play each month when they unlock. In fact, I’ve mostly stopped buying games these days because they keep showing up in Humble Bundles.

If you do pick up the game, and you’re having a tough time getting started, watch some pros at work. Check out my friends EJ_SA or Scott Manley on Twitch.

Source: Humble Monthly