The Evidence

The Giant Filaments in the Galactic Core

MeerKAT radio map of the Milky Way's core. Notice the "vertical" filaments (perpendicular to the galactic plane), which are a couple of light years across and hundreds of light years long. What an image!

Another view.

The filaments seem to be made of synchrotron radiation, which is produced by particles moving at nearly the speed of light through a magnetic field. Nobody knows, though, what gave those particles their energy, since the don't seem to be streaming away from anything.

MeerKAT has also observed these filaments in other galaxies, and more recently other filaments have been discovered that are roughly parallel to the galatic plane ("horizontal").

More: Scientific American, LiveScience.

Moon Race?

Can I just say how ridiculous I find headlines like this, from CNN:

Is NASA losing the moon race?

Because, you know, NASA already won the Moon race, in 1969. Fifty-six years ago! Who cares whether China sends people to the Moon before we go back? We've already been there.

And why are we going back at all? NASA says it's an essential part of their plan to get to Mars, but I don't buy it. 

What an utterly stupid thing to worry about.

Organic Molecules in the Plumes from Enceladus

On October 28, 2015, NASA steered their Cassini spacecraft past the south pole of Saturn's moon Enceladus. The idea was to use Cassini's dust analyzer to sample the plumes of water that regularly erupt from the south polar region (above) and see if anything could be learned about Enceladus' buried ocean. NASA cautioned at the time that Cassini's equipment was not designed for this task, so it might not work very well, plus the spacecraft's speed at closest approach would be about 17.7 kilometers/second (39,000 mph), not exactly ideal for sampling. They also warned that it might take "some time" for results to be made available.

They weren't kidding about the long wait. The first serious study of this study was finally published yesterday in Nature astronomy. 

The results are interesting but not mind-blowing. Besides the small organic molecules everyone expected (methane, ethane), there were some larger finds: benzene or aryl rings, and what appeared to be compounds that also included Oxygen or Nitrogen; they especially think they may have found Benzyl methyl ether.

The discovery of these molecules, if that is indeed what Cassini found (again, the instrument was not designed for this), shows that the ocean contains organic molecules and has some interesting chemistry. But none of this points toward living organisms.

Again, though, this sample was collected in space by a spacecraft moving very fast and analyzed by an instrument not designed to look for larger organic molecules. So these findings in no way rule out life. But they don't make me believe.

RIP Ed Smylie

Ed Smylie (1929-2025) was just one engineer among the hundreds whose genius made the Apollo missions possible. He got his 15 minutes of fame when an oxygen explosion crippled the Command Module of Apollo XIII, forcing the whole crew to move to the Lunar Module. As the engineer in charge of the life support systems, Smylie immediately realized that the CO2 scrubbers in the LM would not be able to handle the load of three men, so he assembled a team to rig up a solution. The episode is wonderfully depicted in Ron Howard's film, and it is to Smylie that someone says, "You, sir, are a steely-eyed missile man." But as Nixon said when he singled out Smylie in giving the Medal of Freedom to the whole Apollo XIII team, "They are men whose names simply represent the whole team."

I love what the Apollo team did, what America did, possibly the biggest ever cooperative human endeavor that was not a war. It was incredible, amazing; using technology 50 years behind the most basic smartphone, humans walked on another world. The wonder of it still wows me and fills me with hope. And with a rage bordering on despair with the people who deny that it happened, who deny that we, humans, just clever apes cursed with violence, built spaceships and sailed to the moon, the people whose minds are too small to encompass the wonder of what we have done and still can do if we put aside our doubts and out differences and dream together about what the future might be.

NASA's Europa Clipper

NASA's Europa Clipper launched yesterday on a SpaceX Falcon Heavy rocket; it is due to arrive at Jupiter in 2030.

The point is to search for signs of life at Jupiter's moon Europa. Europa has an icy crust that is regularly remade and smoothed over, which means there is a big ocean of water underneath it. Electromagnetic studies show that the ocean is salty. There is also plenty of energy, in the form of tidal stresses and Jupiter's intense electromagnetic environment. So, a plausible place to look for life.

On the down side, those same electromagnetic fields would rapidly tear apart many of our key molecules, such as DNA and RNA. So Europan life would have to be quite different from ours. Which is, to me, part of the appeal: I tend to think that the first time we find alien life it will be so strange to us that we will have trouble deciding if it is alive or not.

The Europa Clipper won't drill down to that buried ocean. Instead it will repeatedly fly by the moon's surface, scanning it with a variety of instruments and scooping molecules out of its extremely thin atmosphere to study. We know that Saturn's moon Enceladus sometimes erupts with great jets of water from its subsurface ocean, and while we aren't certain that happens at Europa there is some evidence for it, and NASA is hoping to observe such a plume and fly the Clipper through it.

I am not optimistic that life will be found, but I think the search is worth trying; certainly the chance is higher than on Mars. And even if we don't find life, perhaps we will learn more about these strange worlds and their vast, dark oceans.

Porphyrion and the Fermi Paradox

Today's big news:

Astronomers announced last week that they had discovered a black hole spitting energy across 23 million light-years of intergalactic space. Two jets, shooting in opposite directions, compose the biggest lightning bolt ever seen in the sky — about 140 times as long as our own Milky Way galaxy is wide, and more than 10 times the distance from Earth to Andromeda, the nearest large spiral galaxy.

Follow-up observations with optical telescopes traced the eruption to a galaxy 7.5 billion light-years away that existed when the universe was less than half its current age of 14 billion years. At the heart of that galaxy was a black hole spewing energy equivalent to the output of more than a trillion stars. 

Infrared Image that Sealed the Discovery

The discoverers called this system Porphyrion, after a Greek giant. You can read about this just about anywhere.

I want to write about because for me it ties into the so-called Fermi Paradox. This line of thinking supposedly got started when physicist Enrico Fermi asked, "Where is everybody?" That is, where are all the alien civilizations.

One way to think about the problem is the Drake Equation, which looks like this:

The terms represent the rate of star formation, the fraction of stars that have planets, the fraction of planets where life is possible, the fraction of those planets where life appears, the likelihood that life becomes intelligent, the fraction of civilizations that develop technology we could see from light years away, and the duration of the average such civilization.

I don't see why the obvious rarity of spacefaring civilizations is any kind of paradox; if you simply assume that any one of the middle terms is one in a hundred trillion, the "paradox" disappears.

And one reason I think those terms could be very small is the titanic violence of the universe. The discoverers of Porphyrion think its power is so great that is is rerranging matter across a supercluster of galaxies, and therefore that the uneven distribution of matter in the universe might be partly due to such phenomena. Imagine what would happen to any civilization that got in the way of such a blast. 

These enormous jet systems may be the most striking examples of galactic violence we know of, but lesser violence is everywhere: colliding galaxies, giant black holes, colliding planets, exploding stars. The more I ponder what the galaxy is like, the more I think we are riding a stupendous lucky streak. We got lucky when one of our sun's rocky planets ended up in a zone where water is liquid much of the time, making it possible for life to get going. Life has tenaciously hung on every since, but it has been nearly wiped out several times (or at least complex multi-cellular life has). We have had mega-extinction after mega-extinction, caused by asteroid impacts, volcanism, a planetary ice age, and who knows what else.

And having dodged all of them, we may one day be finished off by another space rock or, if we last long enough, by the expansion of our aging sun.

Our world is a miracle of astonishing improbability, and we should cherish the chance we have been given to thrive.

The Ghost Nebula

Above, new image from Webb; below, Hubble.

The Ring Nebula

Webb space telescope image, shot in visual and near infrared light, with false color. Huge, zoomable image here.

Webb Tours the Gas Giants

Starship Blows Up

The first launch of the SpaceX Starship, the vehicle supposed to one day carry people to Mars, blew up today. The booster failed to separate from the second stage, the whole thing started spinning and then, boom.

Earlier a telescopic view showed that not all of the booster's 33 engines were firing, which seems like a bad sign even if it didn't cause the failure. I have wondered about all those engines ever since SpaceX announced they were going with this design. The reason the Soviets never got to the Moon was that they never got their 30-engine N-1 super-heavy rocket to work, and NASA engineers at the time pointed to the difficulty of making so many engines work together. But I guess computers and controls and such are a lot better now than they were in the 1960s, so maybe SpaceX can do it.

The strange thing about the video of the disaster that SpaceX immediately uploaded to Youtube is the excited atmosphere. The video starts with clips of other SpaceX failures, and when Starship blew up the assembled crowd cheered.

Elon Musk is of the "move fast and break things" school of engineering, and he made SpaceX in that image. His whole approach is that space can be reached much more cheaply if we cut back on the bureaucracy and take more risks. And on the whole it seems to be working; SpaceX launched around the same time as other private space companies but has progressed much faster; its Falcon 9 rocket has made 217 launches, of which 152 were reflights, making it by far the leader in commercial satellite service. Its Dragon capsule is now the main way people and gear reach the International Space Station. Starship, when and if it actually reaches space, will be the most powerful launch vehicle ever made.

Falcon 9 launch vehicle landing on the droneship

So in a sense the whole mission is based on accepting the chance of failure. I don't think the cheerful, excited tone of SpaceX's failure video is all fake. I think that is genuinely the culture they are trying to cultivate, and I have no trouble believing that many of their employees buy into it.

Whether that sort of spirit can really get us to Mars, I have my doubts. I don't have the passion for crewed space flight that animates Musk and people like him, so I am not all that charged up for the mission. If I were in charge of the space budget I would blow up the ISS tomorrow and put an end to all this nonsense about going back to the Moon. We've been there and already know there's no reason to go back. Instead I would send highly capable robots to the moons of Jupiter and Saturn, where there are still discoveries to be made.

But other people feel differently, and if they want to cheer the launch of Starship and then its self-destruction, I wish them all the best.

Webb vs Hubble at the Pillars of Creation

Webb (above) revisits one of Hubble's most famous images (below), showing off its superior resolution. Not sure it's as cool a picture, though. Big files here.

Jupiter's Red Spot Has Shrunk a Lot

Above, drawing by French artist Etienne Léopold Trouvelot, 1880; below, recent NASA image. Trouvelot worked at the Harvard observatory for many years, and Yahoo has put up an interesting collection of his work. Some of his drawings of things like solar flares and sun spots are stunningly accurate.

To Fly on Another World

Just a little hop, but still amazing.

The deniers are already at it; I've received multiple links to posts claiming it must be a hoax, since there just isn't enough air on Mars to support flight. But there is, and we can.

Pieces of an Asteroid, via Hyabusa2

Pieces of asteroid Ryugu brought back to earth by the Hyabusa2 spacecraft, much bigger than the sand brought back by Hyabusa1 in 2010. These pieces were knocked off the surface by shooting it with a steel bullet, which left a crater deep enough that some of them come from beneath the surface. Studying primitive carbonaceous asteroids is supposed to give us a window into the early solar system, and some people think the carbon on Earth's surface was brought here by asteroids of this type.

Anyway it's pretty cool that we can send a robot to an asteroid and have it bring rocks back for us to look at. 

Eighteen Quasars

 

Photographed by the European Southern Observatory's Very Large Telescope

Not Excited about Life on Venus

Lots of buzz in the news this week about two scientific papers arguing there must be life on Venus. They base their conclusion on the discovery of phosphine (PH3) in the Venusian clouds. Which I admit is pretty cool. Phosphine seems to be a byproduct of respiration among some bacteria, so it might be a sign of life. These scientists go on to say that no known inorganic process could produce it outside the titanic pressures of Jupiter's inner atmosphere, so there must be life  on Venus.

Maybe. But since we understand Venus' strange atmosphere only a little, and its conditions are very difficult to replicate on earth, who knows? Claims that methane and oxygen found on Mars are evidence of Martian life have not exactly panned out, and incidentally nobody knows what made those gases, either.

I despise scientific arguments that go, "I can't think of any other explanation, so it must be alien life." For one thing we still don't even understand how or why bacteria on Earth produce phosphine, so it might turn out to be a fairly simple reaction, 

I support dreaming up some way to study the Venusian clouds and sending a spacecraft to do it, but I am not optimistic that it will find life. I don't think we understand nearly enough about the universe for this sort of leaping to conclusions.

Ingenuity, the Mars Helicopter

The next rover for Mars, Perseverance, is scheduled to launch on July 20. Riding along with it is a bit of new technology: a tiny helicopter that is supposed to be the first machine to fly in Mars' thin atmosphere. This is a proof of technology mission, not really about exploration, and the mission description just says "one or more flights within 30 days." I find myself wondering why the NASA's press pages make so little of the name; I had to search all the way to the "Mission Fact Sheet" to find that it even has a name. I suppose NASA is trying to keep expectations low, afraid that if they talk too much about it by name people will be disappointed if it only makes one 10-second flight, or never gets off the ground at all.

Ingenuity weighs 1.8 kg (4 pounds) and its rotors span 1.2 m (almost 4 feet). The blades are supposed to spin at 2400 rpm. It does have cameras, so it may get us some nice photographs of the rover in the Martian landscape.

Landing for Perseverance is scheduled for February 18, 2021. Maybe they will fly the copter to celebrate my birthday on the 26th.

Juno at Jupiter

Still sending back amazing images. Above, the shadow of the moon Io falls on the planet.

Photomontage of the south polar region.

A vortex.

Infrared image showing cyclones around the south pole. One of these is new since the last time Juno photographed this region, so the number and arrangement is not stable.

Today's Big Number

The mass of the Milky Way Galaxy is about 1.5 trillion solar masses. It contains about 100 billion stars. The matter we can see accounts for only 16 percent of the mass, with the rest being "dark matter."