Y’know, every now and again you just need to sit back, breathe deeply, and watch a stunning and lush time-lapse video of thunderstorms and stars circling in the sky.

Happily, Randy Halverson has made one for you. Called “Field of View”, the 3+ minute trailer is available in resolution up to 4k, so make it big and enjoy:

Oh, my. I love watching the stars above a thunderstorm, and also the bubbling, rising currents of warm air percolating at the tops of those cumulonimbus clouds. A favorite is also to try to spot geosynchronous satellites in the views of stars; as the stars move across the screen due to Earth’s rotation, the geosynch sats look like they’re standing still in the sky.

Like I said, this is a trailer; the full-length version is available for download, as well as many of Halverson’s other lovely animations. I’ve written about them before, so have a look-see:

• Trail’s End
• Horizons
• Tempest Milky Way
• Huelux

… and honestly so many more it’s probably just best to go to his site and take a look. You’ll be happy you did.

Eight minutes and 35 seconds after a SpaceX Falcon 9 rocket launched into space, the first stage booster came back to Earth and successfully landed vertically on a barge floating in the Atlantic Ocean.

This was seriously one of the most amazing things I have ever seen in my life. Watch for yourself:

Like I said. Amazing.

The previous attempts to bring the booster down at sea have met with, um, limited success, a few with what SpaceX CEO Elon Musk has called “rapid unscheduled disassembly” events. In other words, boom.

The idea behind this is that building a first stage Falcon 9 booster is expensive, but cleaning, checking out, refurbishing, and relaunching one is much cheaper. Those steps are still to come, and we’ll see what the real-world costs and testing yields. But for now, the critical first step has been taken.

I’ve described why this feat is so technically challenging before; the first stage booster is moving eastward at about 6,000 kph (3,600 mph) when its engine cuts off (the second stage takes over from there). The booster has to flip over, slow down, put itself on the right trajectory, come in over the floating barge, then relight its engines at just the right amount to kill its velocity and land upright. Because it’s hundreds of kilometers east of Florida by the time it starts to come back, it helps to have a landing platform out to sea to save rocket fuel. In December, the booster successfully touched down vertically back at the landing site, and this is the first time it’s been done at sea. SpaceX now has shown it has the flexibility to retrieve the booster under a variety of launch configurations.

Incidentally, the barge is named Of Course I Still Love You, after a spaceship in a novel by Iain Banks. 

Mind you as well, the primary mission was to launch a Dragon capsule full of supplies to the International Space Station, and that is going well right now too. The Dragon was placed in to orbit by the Falcon 9 second stage minutes after the first stage booster landed. The solar panels deployed (needed to power the capsule for its two-day journey to catch up to ISS), and it’s on the right trajectory.

Supplies on board include food, equipment, and live mice (for an experiment dealing with muscle wasting in microgravity). Also included is a bouncy castle an inflatable habitat built by the Bigelow Aerospace, literally a balloon that will be attached to a module on ISS and inflated to test how such a habitat can be used in space. They are much lighter and less expensive than building a rigid structure, and may well be used commonly in the future of space exploration.

All of this is boggling. Mind you, the last attempt by SpaceX to send a Dragon to ISS ended in the rocket disintegrating moments after takeoff when a strut broke inside the booster, causing a helium tank to explode and rupture the booster’s outer skin. There have been a few Falcon9 launches since, but this is the first to go back to ISS. And it’s on its way.

My sincere and slack-jawed congratulations to SpaceX, Elon Musk, and everyone who helped put this bird into space, and brought a piece of space history back to Earth. Well done.

I’m not a geologist. I’m an astronomer, and a general science enthusiast, with an extra dollop of enthusiasm set in reserve for geology.

It’s one of the reasons I’m so enthralled with asteroid impacts. I get both astronomy and geology in one fell swoop (with a not-incidental soupçon of dinosaurs, too, for somewhat obvious reasons)!

But, since it’s not my field, I still get baffled when I see certain things. Happily, I have a bunch of geologist friends (scientists hang out in packs) to whom I can send questions. Other times, the answer is right in front of me.

The image above is from the Lunar Reconnaissance Orbiter Camera and shows a crater on the Moon nicknamed Chappy (it formed in the much larger Chaplygin crater). It’s about 1,400 meters across (a bit bigger than Barringer crater in Arizona), which means that whatever asteroid or comet slammed into the Moon here exploded with the yield of about a 30 megaton bomb—about as big as any nuke ever detonated by humans. The fresh pattern of ejected material around it suggests a very young age. How young is hard to know, maybe only a few millennia, maybe more. But over time micrometeorite impacts and the solar wind soften and fade those features, so the crater isn’t, say, millions of years old.

The pattern around Chappy shows broad, wide streaks, seemingly overlapping with streaks of different contrast, looking very much like the petals of a flower.

It’s that lovely pattern that got me thinking. Sometimes craters have rays, thin, long, linear features that can extend for thousands of kilometers in bigger impacts. Rays are caused by plumes of material ejected from the impact event; the material blasts outward then settles onto the surface making the radial streaks.

When the Moon is full, the huge crater Tycho shows prominent rays, one of the more iconic features on the Moon. I’ve seen it and them hundreds of times through my own telescope, one of the few really interesting features visible when the Moon is full.

That biased me. I’ve written about craters that have these broader petal patterns before, ascribing to them the same formation mechanism as rays: collapsing plumes from the impact.

But that’s wrong. In the LROC blog post about the image, they give the correct mechanism: ground flow. Material blasted out from the impact flowed along the lunar surface, hugging the ground, moving up and down over the hummocky surroundings, and flowing around or deflected by obstacles. That also explains the shapes of the petals; the endpoint of each (the terminus) is where the material stopped flowing, either as momentum was lost due to friction or the material simply ran out. Some flows are thicker, some less dense, which can give them different brightnesses on the ground.

When I read that, I almost slapped my forehead. Of course those can’t be from plumes that traveled up and away; the shape is all wrong. But I was prejudiced from what I already knew, not thinking there could be other mechanisms at work.

I urge you to subscribe to the LROC images blog; they post truly beautiful and fascinating images taken by the camera, with a description written by someone familiar with the data. It’s a seemingly endless source of wonderful science.

P.S. At the bottom of their Chappy post is an interactive widget where you can scan, pan, and magnify the terrain around Chappy, and it’s incredible. Go.

Perhaps you’ve heard that there are a hundred billion galaxies in the Universe. That’s a soul-crushing number, so vast and unreachable that it’s literally hard to believe.

Let me make a believer out of you.

That photo above is from the venerable Hubble Space Telescope. It’s part of a colossal effort by astronomers, dubbed the Frontier Fields program, to peer as deeply as possible into a half-dozen galaxy clusters, veritable cities of galaxies that can contain thousands of galaxies like our own. The combined gravity of these clusters can bend light, which magnifies and amplifies the light coming from even more distant galaxies on the other side of the cluster from us. This “gravitational lensing” allows us to see fainter, more distant galaxies than would be possible without the clusters' aid.

Clusters are where galaxies are more common … but the image above does not show such a cluster. Hubble is a single telescope equipped with several cameras. Each camera sees a slightly different part of the sky when Hubble is pointed at a target. Two main cameras were utilized for Frontier Fields: the Advanced Camera for Surveys (or ACS), and the Wide Field Camera 3 (WFC3).

For this image, the cluster Abell 2744 (also called Pandora’s Cluster) was the main target, and was being observed by WFC3. At the same time, ACS was viewing the nearby part of the sky shown above.

As you can see, it’s filled with galaxies. I scanned the full resolution 6,750 x 6,500 pixel image, and only found a dozen or so objects I could unambiguously identify as stars (point sources like stars get those cross-shaped diffraction spikes through them; extended objects like galaxies smear out the spikes so they become invisible).

In other words, for all intents and purposes, every object you see in that photo is a galaxy, each a sprawling collection of gas, dust, and countless billions of stars, each thousands or even hundreds of thousands of light years across.

I have two points to make here.

First, note how few of the galaxies have what you might think off as overall structure. Sure, many are lens-shaped, spiral, elliptical; but the vast majority are distorted, irregular, peculiar. I would venture that most of these objects you can see are billions of light-years away, so far away that the light we see from them left them when the Universe was far younger. When we look at the nearby Universe, many galaxies do have overall structure, obviously so. But in the distant Universe, things were different.

This right away tells you a fundamental cosmological truth: The Universe changes. It was different when it was younger.

This is a critical piece of evidence that the Universe began. It had a start. It’s one of the many, many pieces of evidence strongly supporting the Big Bang model of the origin of the cosmos. There may have been something out there before it, but what we see now reflects what happened then.

My second point is somewhat more prosaic, though no less profound.

How many galaxies are in this image? Counting them is a daunting task, so I made it simpler on myself: I looked a series of 650 x 675 pixel subsections, and counted the galaxies in each of them. Since the full image is 10 times bigger on each side, the average number of galaxies in each subsection should be 1/100^th the total in the image.

I found very roughly 50 identifiable galaxies per subsection. That means the image contains roughly 5,000 galaxies.

The image itself is a tiny, tiny slice of the sky, only a little over three arcminutes on a side. An arcminute is an angular measure of size; there are 60 arcminutes in a degree. The Moon on the sky is about half a degree across, so you can see this is indeed a small piece of cosmic real estate.

There are about 41,000 square degrees in the entire sky, which in turn means there are 41,000 x 60 x 60 = about 150 million square arcminutes in the sky. The image above is about 10 square arcminutes, so it would take 15 million such observations to cover the entire sky.

Perhaps you see where I’m going with this. If there are 5,000 galaxies in the image, and it would take 15 million such fields to cover the sky, then there must be about 5,000 x 15 million = 75 billion galaxies visible in the sky. At least; some will still be too faint to see even in this Hubble image.

Now do you see? Just by taking this observation and applying some high school math, we have discovered that the Universe has something like a hundred billion galaxies in it.

And each of those galaxies has billions of stars. That means there are something like a sextillion stars in the Universe: 1,000,000,000,000,000,000,000 suns.

And it’s reasonable to think that most of those stars have planets, perhaps multiple planets. How many are Earth-like? How many have life?

And yet, in all that—and perhaps more—there’s only one planet just like Earth, only one of all of us. One of you.

Look back at the image taken by Hubble. Look at it closely. The Universe is so vast it may be impossible for us to grasp its size and scale; yet by studying it, by embracing it, we see that our being a part of it is special.

If there is one most amazing thing that astronomy, that science, has shown us, I believe it is that.

Soon.

And yes, those are my goats. That's Sam standing on my daughter's back, and Clayton plotting world domination behind him.

I just thought y’all deserved to see this stunning and moody portrait of the comet 67P/Churyumov-Gerasimenko, taken by the Rosetta spacecraft on March 27, when it was about 329 kilometers away from the comet’s rocky and icy solid nucleus.

Although it looks like the Sun is directly behind the comet, it’s not quite; the angle from the spacecraft to the comet to the Sun is about 160°, with the Sun off the frame above and a bit to the right. You can see the lit “crescent” comet, its two lobes mostly backlit. Vents in the surface are warmed by the Sun, and ice there sublimates, turning directly into a gas, expanding, and blowing away from the comet. That’s what forms those lovely fanlike jets of material.

Some of the jets look curved, and I suspect that’s due to the rotation of the comet; the material flung away moves in a straight line, but as the comet spins, each particle is flung away in a slightly different direction, creating curved or spiral patterns. This is called the “sprinkler head effect” and is seen in many objects, including comets, stars, and even rocket flights.

To give you a sense of scale, the big lobe of the comet is about 4.1 kilometers across, and the smaller one about 2.6 kilometers. The jets fan out, and eventually become the comet’s coma—the fuzzy cloud around the solid nucleus—and the tail.

This image was taken specifically to study the material around the comet; it’s a relatively long four-second exposure, and the camera was set to be more sensitive to light to capture faint details. And yes, I’m pretty sure those are actual stars in the background. This really is quite a lovely picture.

After several months of close passes, Rosetta was recently sent on a long-distance excursion that went to 1,000 kilometers from the nucleus to study the space environment surrounding the comet now that it’s passed its closest point to the Sun and is moving outward again in its orbit. The spacecraft is on its way back to the comet now, and will pass just 30 kilometers over the surface in a few more days—this is referred to as a “zero phase flyby,” which means the Sun will be shining directly down on the comet from Rosetta’s view (I wonder if the spacecraft might even see its own shadow, which it’s done before, though it may be too distant for the shadow to be clear).

It’s nice to see Rosetta still performing well. But not for much longer: The end of the mission is planned for September 2016, when the spacecraft will be commanded to land (hopefully gently) on the comet’s surface.

But that’s months away, and there’s much more to be learned from this spectacular and frankly weird object as it heads away from the Sun and its warmth, back into the colder depths of the solar system past Mars and Jupiter.

I wonder … the comet orbits the Sun every six years or so. Will we ever venture back? Will future robots, or even humans, come to find Rosetta resting on the comet’s surface, dusty and frosty from the constant exhalations of the active object? It’s a nice thought. I hope so.

If you’ve been reading my blog for any amount of time at all, I really shouldn’t need to do any urging to get you to watch a gorgeous time-lapse video of aurorae.

So, here:

Breathtaking. There is something particularly striking about the luminescent purple and green aurorae together that demands my attention. And the ending! Lightning storm with aurorae! Wow.

The photography is by Shawn Malone of Lake Superior Photo. Funny; I lived in Michigan for three years and never saw an aurora. But maybe the lights of Ann Arbor are too bright.

As for the aurora itself, they’re caused when the Sun floods interplanetary space with subatomic particles in the solar wind. These are channeled down into or atmosphere by Earth’s magnetic field, causing the air to glow depending on what atom or molecule is energized by the event.

I have a page full of links to explanations about aurorae if you want to learn more. And you should; I find it very pleasing that such interesting scientific phenomena can produce such displays of utter, pure beauty. When I see something like this—sheets of glowing filaments, flickering colors, draping waves of light—I want to know why. And when I find out, the depth of my appreciation grows.

As Carl Sagan said:

It is sometimes said that scientists are unromantic, that their passion to figure out robs the world of beauty and mystery. But … it does no harm to the romance of the sunset to know a little bit about it.

I think Sagan could have gone farther. I would have added, “… and in fact, it enhances its majesty greatly.”

I love being surprised by a picture.

I first saw the photo above when my friend Bobak Ferdowsi tweeted a link to it, having seen it himself on the RidingWithRobots Twitter feed. When I saw it, I literally gasped. It’s a view from the Opportunity rover on Mars, showing a dust devil whipping across the floor of a huge crater.

Oh my, yes. Let me explain.

I write a lot about the Curiosity Mars rover, of course, the powerful mobile science lab currently moving across the surface of the red planet. But don’t forget about Opportunity, a smaller but no less successful and ambitious rover that is still going strong after an astonishing 12 full years on Mars.

Right now Opportunity is skirting the rim wall of Endeavour crater, a 22 kilometer impact feature. From orbit, measurements show the presence of phyllosilicates in the crater rim rocks—minerals that form when water is present; more evidence that long ago, Mars was wet. Opportunity has been poking around this area for quite some time to see for itself what it can find.

Carved out along the western rim of the crater is a notch, named Marathon Valley, which runs east-west for about 300 meters and is a few dozen meters wide. Opportunity is inside that valley, investigating the northern and southern walls.

It was commanded to make a steep ascent along one of the ridges marking the edge of the valley, but after many attempts, the wheels simply couldn’t get enough traction to move Opportunity up the ridge. Engineers commanded it to backtrack and try a different route.

Looking back down over ground it had already covered, facing toward the interior crater, Opportunity caught the scene in the photo above. You can see the disturbed surface where the six wheels dug in, and the rolling hills in the valley. Past that is the floor of the crater … and the whirling, towering dust devil.

Mars has an atmosphere, but it’s thin, less than one percent the pressure of Earth’s air at sea level. But it’s enough to move around, make wind. If a horizontal air flow passes over a warmer section of ground, a rolling vortex of air can be formed. The rising air lifts it up, making it vertical, and you get a dust devil. These look like tornadoes, but dust devils are far weaker, and form from the ground up, while tornadoes drop down from the bottoms of clouds.

Opportunity has two cameras side by side in its navigation camera, to provide stereoscopic views. Each took a shot of the dust devil, and I combined them into a flicker animation, which gives a bit of illusion of depth. You can see the topography of the shot a little better:

Dust devils are frequently seen on Mars. Besides capable of creating almost unbelievable calligraphy on the Martian surface as lighter dust is swept away, revealing darker rock underneath, dust devils have been a boon to Opportunity: They clear the accumulated dust off the rover’s solar panels, giving it a boost in power. This was unexpected when the rovers were sent, but accepted gratefully by mission engineers.

So dust devils are a kind of good luck charm for the rover team. But they’re more than that to me ...

When I read about water on Mars a billion years ago, and rovers poking at sedimentary and metamorphic rocks altered by that water, it feels a little bit like finding fossils; fascinating and fun but a reminder that Mars used to be a happening place.

But it still is. Those dust devils are a reminder that Mars isn’t some dead world, it’s still an active one. Maybe the pace has slowed over the past eon or two, but there’s still a lot to see and explore. Opportunity proves that every day.

Are you, or do you know someone who is:

• Between 18 and 24 years old (on or before June 10, 2016)?
• In good physical health?
• A legal resident within the 50 United States?
• Enrolled at a learning institution?

And most importantly, loves space exploration and wants a chance for a free ride on a Zero-G airplane?

Then my pal Emily Calandrelli has a deal for you. She’s the host of “Xploration Outer Space,” and they’re partnering with Zero Gravity Corp. to hold the Student Astronaut 2016 contest.

They’re looking for students to create a three-minute (or shorter) video about space exploration and microgravity, and the winner will get to ride on a plane that simulates microgravity! Here’s Emily to explain:

There are rules and restrictions, so make sure you check them out. The contest closes on May 15 so get cracking. This will change your “What I Did on Summer Vacation” essay experience forever.

Over the weekend, on Saturday, the private rocket company Blue Origin did it again, again: For the third time it launched the New Shepard rocket on a suborbital flight, reaching a height of more than 100 kilometers (the generally accepted line demarking a trip into space), and brought it back safely to Earth again.

To be clear: It was the same rocket for all three flights. That’s fantastic news!

The first flight above the 100 kilometer mark (called the Kármán line) was in November of 2015, and the second in January 2016. There had been some earlier tests at lower altitudes as well.

According to Blue Origin CEO Jeff Bezos’ tweets, it all went smoothly. The rocket soared into the sky, deployed the (uncrewed) crew capsule, then fell back to Earth. They then tried something new: The rocket engine was off during most of the descent, and then did a “quick restart” at a mere 1,000 meters above the ground! It fired up rapidly and brought the booster down to the ground safely. Blue Origin has the video highlights of the mission:

I can't believe how close to the ground the engine was when they restarted it. Consider my hair raised.

Not only that, but two scientific experiments were on the crew capsule; one was to see how dust aggregates in microgravity (as a precursor to understanding how planets form).

And the other? It was a “box rocks,” designed to test how rocks and smaller material (called “regolith”) behave in microgravity, an important step in seeing how the very low gravity on the surfaces of asteroids sorts that material. This experiment was crated at the Southwest Research Institute, and I’m very pleased to note it’s the brainchild of my old friend Dan Durda!

Dan and SwRI are very serious about suborbital science, as well they should be.

Mind you, the New Shepard rocket didn’t go into orbit; it went up and then back down again. But the capsule experiences free fall for about three to four minutes, which is enough time to do a lot of science if you’re clever. I’m very happy to see Blue Origin doing this; it’ll be a while before it can put humans in its capsule, and in the meantime a lot of good work can be done when it does test flights like this one. My friend Alan Boyle has more over at Geekwire, including some videos taken by onlookers.

It’s very exciting to see a new age of reusable rocket tech really starting to come into its own. I’ll note that they’re also working on a new engine, the BE-4. This is a powerful engine, and Blue Origin has partnered with United Launch Alliance to use it in an upgraded Atlas V rocket, which currently uses the Russian RD-180 engine. That has been the source of some controversy, so it’s very good indeed to see them moving away from dependence on Russia.

Congratulations to Blue Origin on all its success!