Apollo revisited: Cosmic rays buzz Buzz Aldrin’s eyes

Buzz Aldrin, Apollo astronaut and second to walk on the moon, demonstrates the ALFMED device astronauts used to record the cosmic rays that flashed inside their eyeballs during their journeys to the moon and back. Credit: NASA

With the 45th anniversary of the Apollo 11 moon landing approaching this weekend, let’s look back at a peculiar discovery made while astronauts Buzz Aldrin and Neil Armstrong left the safety of Earth for the lunar unknown.

Earth’s atmosphere and magnetic field protects us from cosmic rays, which are high-speed protons and other atomic nuclei that shoot across the galaxy like so many submicroscopic billiard balls. They pack a punch. The most powerful contain the same energy as a baseball traveling at 56 mph. Scientists believe cosmic rays originate from exploding supernovae.

En route to the moon in 1969 Buzz Aldrin reported seeing flashes in his eyes in the darkened cabin of the command module. Neil Armstrong noticed them too. Back in 1952, physicist Cornelius Tobias predicted that cosmic rays could interact with light-sensing cells in astronauts’ eyeballs to generate the perception of flashing lights.

Flash patterns observed by Apollo astronauts.

After Aldrin and Armstrong reported their experience, NASA asked future astronauts to be on the lookout for the same and report anything unusual. Later missions even included a special device called the ALFMED (Apollo Light Flash Moving Emulsion Detector), a helmet the astronaut wore to dark-adapt the eyes to better see the flashes. It also held film that recorded cosmic ray hits that were later correlated with the times flashes were seen.

The device conclusively proved that the flashes, dashed lines and occasional glowing puffs the space travelers reported were clearly caused by cosmic rays.

While not every Apollo astronaut saw them, most did and described them as white or colorless spots, stripes, streaks, explosions and multiple tracks. They occurred on average once every 2.9 minutes. For some, the flashes were so frequent it made getting to sleep a challenge.

A cosmic ray hit on the sensor in a camera appears as a segmented line. Credit: NASA/Don Petit

You don’t have to go all the way to the moon to experience this ocular light show. Free from the protection of the atmosphere, International Space Station (ISS) astronaut Don Petit saw them from Earth orbit, describing the flashes poetically as ‘fairies’:

“In space I see things that are not there. Flashes in my eyes, like luminous dancing fairies, give a subtle display of light that is easy to overlook when I’m consumed by normal tasks. But in the dark confines of my sleep station, with the droopy eyelids of pending sleep, I see the flashing fairies.”

It’s thought that as a cosmic ray passes through the retina it causes rod and cone cells to fire, creating the perception of light. According to Petit, a straight-on ray looks like a fuzzy dot, a ray at an angle, a segmented line. Some tracks even have branches like lightning that resemble sparks. Cosmic rays contribute most of the radiation received by astronauts on board the ISS. To date, no one has reached the dosage limit and had to return to a desk job on Earth.

You might think the hull of the space station would keep away cosmic rays, but they’re so tiny and so energetic they pass right through. They can affect electronics too, locking up computers and destroying pixel elements on a camera’s sensor. Petit says you can reboot the computers, but the effect on the sensors is cumulative. Over time, pictures become dotted with pixelly white ‘snow’. Time for a new CCD.

Artistic impression of cosmic rays entering Earth’s atmosphere. Primary rays strike the upper air and create rich showers of less energetic particles. Credit: Asimmetrie/Infn

Studies of cosmic rays on the eyes and bodies of astronauts continues right up through the present with the Alteino-Sileye3 detector used to monitor the radiation environment and light flash phenomenon in the space station.

Cosmic ray flashes remind me of the unexpected benefits of taking a trip to a far-away place. No one considered the possibility (except theoretically), yet by going, we not only discovered a new phenomenon but opened up a lively field of study.

Supermoon fun / Mars-Spica conjunction tonight / Venus visits Mercury at dawn

Passing clouds create a colorful corona around last night’s full moon. Credit: Bob King

The moon coaxed many of us out for a look last night. We had clear if hazy skies in my town which made for a striking display of lunar crepuscular rays. Lunar what? If you’ve ever seen sunbeams poking through clouds in the afternoon or evening, you’re looking at crepuscular rays. Crepuscular comes from the Latin word for ‘twilight’ as the beams are often noticed during early evening hours around sunset.

A delicate display of crepuscular rays radiates across the sky above a cloud-shrouded moon. Credit: Bob King

Bright rays shining through gaps in the clouds alternate with shadows cast by other clouds to form a spreading fan of light and dark columns. The dustier or smokier the air, the more vivid the crepuscular display. Notice how they appear to converge on the moon. This is an optical illusion. The rays are perfectly parallel just like endless rows of beans on a farm that appear to merge together in the distance.

Last night’s supermoon shines back from a mobile phone. I took the picture by holding the phone’s camera lens directly over the eyepiece. Credit: Bob King

Many of us like to take pictures of the moon through a telescope using nothing more than a mobile phone. If you’ve tried this, you know how tricky it is to hold the phone camera in the right spot over the telescope eyepiece. It takes a few tries, but the results can be remarkable. Phones do well on bright celestial object like the planets, moon and sun (with a safe filter). Despite what some ads might tout, phones can’t yet record fainter things like galaxies, nebulae and the like.

Orion Telescopes makes an adaptor to hold a phone securely over the telescope. While it gets mixed reviews, you might want to consider it if you don’t want to invest in a separate camera but would still like to create an album of your own astrophotos.

Mars (top) and Spica last night July 12. The difference in color between the rusty planet and blue-white star was very easy to see. Mars will remain near the star the next few nights but change its position like the hour hand on a clock. Credit: Bob King

I know we’ve all been moonstruck the past few nights, but did you happen to notice how close Mars and Virgo’s brightest star Spica have become? Last night they were separated by only 1.5 degrees; tonight they’ll be in conjunction a squinch closer at 1.3 degrees. Watch for the duo in the southwestern sky near the end of evening twilight.

Mars moves eastward and soon departs Spica en route to its next notable appointment, a conjunction with Saturn on August 25. Have you been up at 5 a.m. lately? Me neither. But my crystal ball a.k.a. Stellarium program tells me that Venus and Mercury are playing tag an hour before sunrise in the eastern sky.

Venus and Mercury shine together low in the northeastern sky during morning twilight the next couple weeks. This map shows the view tomorrow morning 45 minutes before sunrise. Venus will be about 10 degrees (one ‘fist’) high, Mercury half as much. Source: Stellarium

Mercury reached greatest elongation (distance) west of the sun yesterday and now appears about five degrees high in the northeast some 45 minutes before sunrise. Look for it about the same distance below brilliant Venus. This is a good apparition of Mercury, and having Venus nearby makes it easy to spot.

The swiftest-moving planet will hang near the goddess planet for the next two weeks, all the while growing in brightness as its phase fills out from crescent to full.

Supermoon feast begins – it’s three in a row, baby!

Overnight tonight we’ll see the first of three supermoons in July, August and September. Credit: Gary Hershorn / Reuters

If the moon’s orbit were circular there’d be no such thing as ‘supermoons’, the occasional, extra-large full moons we see about once every 13 months. But circular orbits are exceedingly rare. Most celestial bodies dance about each other in ellipses. At one end of the ellipse, the two bodies are closest; at the other end, farthest.

The moon revolves around Earth in an elliptical orbit, passing through perigee (closest point to Earth) and apogee about once each month. When perigee occurs at full moon, we see a supermoon. Credit: Bob King

When the full moon coincides with its time of closest approach to Earth – called perigee – its disk can be up to 14% bigger and 30% brighter than typical full moons. In 2014 we get three consecutive perigee or supermoons in a row. The first occurs tomorrow morning July 12 at 3:28 a.m. CDT about 3 hours before the moment of full moon. Not a perfect match but close.

The next supermoons happen on August 10 (1 p.m. CDT) and September 8 (10:30 p.m.)

“Generally speaking, full moons occur near perigee every 13 months and 18 days, so it’s not all that unusual,” said Geoff Chester of the US Naval Observatory. “In fact, just last year there were three perigee Moons in a row, but only one was widely reported.”

The size difference between an apogee (foreground) and perigee or supermoon. Would that we could see them simultaneously to truly appreciate their different sizes. Credit: Tom Ruen

Supermoons get a lot of press because the word ‘super’ attached to anything these days naturally attracts attention.

While the phenomenon is very real, it’s also really hard to see because there are no rulers you can hold up to the sky to compare the size of one full moon to another. They ALL look big especially when the full moon’s near the horizon. That’s when the infamous ‘moon illusion’ kicks in and psychologically inflates the lunar disk up another notch.

Still, there’s every reason to go out and enjoy a full moon, super or not. The striking beauty of a moonrise, the curious mix of light and dark areas representing ancient crust (light) and titanic impact craters (dark) and the soft, yet stark illumination of the landscape where mystery abounds in every shadow. I could go on and on.

Rosetta sends postcard of a growing comet

Comet 67P/Churyumov-Gerasimenko photographed by Rosetta’s narrow angle camera on July 4, 2014 at a distance of 22,990 miles. The three images are separated by 4 hours, and are shown in order from left to right. The comet has a rotation period of about 12.4 hours. Credit: ESA/Rosetta/MPS for OSIRIS Team

A quick update and image. The European Space Agency’s Rosetta spacecraft moved to within 22,990 miles (37,000 km) of Comet 67P/Churyumov-Gerasimenko on July 4 and took these fresh images. That’s only about 700 miles farther than the belt of geosynchronous communications satellites orbiting the Earth.

While the new photo is still too low res to show surface features, we can now clearly see the comet’s irregular shape.

Hubble spies ‘pearls on a string’ in distant galaxy merger

In this new Hubble image shows two galaxies (yellow, center) from the cluster SDSS J1531+3414 have been found to be merging into one and a “chain” of young stellar super-clusters are seen winding around the galaxies’€™ nuclei. The galaxies are surrounded by an egg-shaped blue ring caused by the immense gravity of the cluster bending light from other galaxies beyond it. Click to enlarge. Credit: NASA/ESA/Grant Tremblay

On a summer night, high above our heads, where the Northern Crown and Herdsman meet, a titanic new galaxy is being born 4.5 billion light years away. You and I can’t see it but astronomers using the Hubble Space Telescope just released photographs today showing how the merger of two enormous elliptical galaxies will one day create one of the heavyweights of the universe.

The two giants, each about 330,000 light years across, are members of a large cluster of galaxies called SDSS J1531+3414. They’ve strayed into each other’s paths and are now helpless against the attractive force of gravity which pulls them ever closer.

A few examples of merging galaxies. NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), K. Noll (STScI), and J. Westphal (Caltech)

Galactic mergers are violent events that strip gas, dust and stars away from the galaxies involved and can alter their appearances dramatically, forming large gaseous tails, glowing rings, and warped galactic disks. Stars on the other hand, like so many pinpoints in relatively empty space, pass by one another and rarely collide.

Elliptical galaxies get their name from their egg-like oval shapes. They lack the spiral arms, rich reserves of dust and gas and pizza-like flatness that give spiral galaxies like Andromeda and the Milky Way their multi-faceted characters. Ellipticals, although incredibly rich in stars and globular clusters, generally appear featureless.

The differences between elliptical and spiral galaxies is easy to see. M87 at left and M74, both photographed with the Hubble Space Telescope. Credit: NASA/ESA

These two appear to be different. Unlike their gas-starved brothers and sisters, they’re rich enough in the stuff to induce star formation during the merger. Take a look at that string of blue blobs stretching across the center – astronomers call it ‘beads on a string’ star formation. The knotted rope of gaseous filaments with bright patches of new star clusters stems from the same physics which causes rain or water from a faucet to fall in droplets instead of streams. In the case of water, surface tension causes water to ‘snap’ into individual droplets; with clouds of galactic gas, gravity is the great congealer.

Close up of the two elliptical galaxies undergoing a merger. The blue blobs are giant star clusters forming from gas colliding and collapsing into stars during the merger. Click for the scientific paper on the topic. Credit: NASA/ESA/Grant Tremblay

Nineteen compact clumps of young stars make up the length of this ‘string’, woven together with narrow filaments of hydrogen gas. The star formation spans 100,000 light years, about the size of our galaxy, the Milky Way. Astronomers still aren’t sure if the gas comes directly from the galaxies or condensed like rain from X-ray-hot halos of gas surrounding both giants.

The blue arcs framing the merger have to do with the galaxy cluster’s enormous gravity, which acts like a lens to bend the light of more distant background galaxies into curvy strands of blue light that are highly distorted images of real objects.


Milky Way and Andromeda collide in 4 billion years – a simulation

Four billion years from now, Milky Way residents will experience a merger of our own when the Andromeda Galaxy, which has been heading our direction at 300,000 mph for millions of years, arrives on our doorstep. After a few do-si-dos the two galaxies will swallow one another up to form a much larger whirling dervish that some have already dubbed ‘Milkomeda’. Come that day, a hard stellar rain’s a gonna fall.

Huge sunspots scar the sun this week

Ten groups including three visible with the naked eye protected with a safe filter dot the sun today. Photo by the Solar Dynamics Observatory (SDO) taken at 8 a.m. CDT today July 9. Credit: NASA

A trio of impressive sunspot groups are parading across the sun’s face this week. Regions 2108, 2109 and 2110 are all closely-spaced and near the center of the disk today. All three require nothing more than a pair of eyes and a safe solar filter to view.

The sun seen through a standard 200mm telephoto lens and solar filter this morning gives you an idea of how the big sunspot groups look to the naked eye. Credit: Bob King

I took a look through my handy #14 welders glass this morning and saw 2110 distinctly; the other two groups blended into a single ‘spot’ at first. Looking closely I could barely split them into two separate dots. The view was spectacular at 30x in my little telescope with a total of ten sunspot groups and lots of fine detail in the three biggest.

Given high sunspot counts, the chance for flaring has been increasing in recent days. Today there’s a 75% chance for moderately strong M-class flares and 20% chance for the most powerful X-class variety.

Safe solar filters come in several varieties of optical / coated plastic and glass. Click to see ones you can purchase from Rainbow Symphony. Credit: Bob King

Curiously, none of the three biggies has shot off a large flare in the past day or two; they’re all currently stable. But the inconspicuous group 2113 fired off a beefy M6 flare only yesterday. It’s not expected to affect Earth, but because 2113 hides a complex magnetic field, future M-class or stronger blasts may be possible.

M6-class solar flare eruption from sunspot group 2113 captured July 8, 2014 at 11:24 a.m. by SDO. Credit: NASA

It seems like we’re due for aurora, so I’d be surprised if the current activity doesn’t lead to at least a minor storm soon. I’ll keep you updated.

Viva Las Vegas! Strange sights from my airplane window

A puffy cumulus cloud stands up from the rest on my return trip from Las Vegas over the weekend. Credit: Bob King

Are you like me and try to get a window seat on your cross country flights?  I always bring a book but never read it because of the constant but pleasant distraction of staring into space 35,000 feet above the surface of the planet.

I just returned from a trip to Las Vegas. A combination of pure chance and a friendly ticket agent landed me window seats on both flights. Since it’s summer, the sky featured plenty of towering cumulus clouds, but as we approached the City of Sin, a dark presence grew across the eastern horizon. What resembled an approaching storm was actually the shadow of Earth creeping upward into the sky.

The Earth’s shadow cast on the atmosphere looks like a dark blue-purple band along the horizon. Above it glows the pale orange ‘Belt of Venus’ created by sunset light reflecting off the atmosphere. Anti-crepuscular rays (shadows cast by clouds in the direction of the sun) are also seen. Credit: Bob King

We see this all the time from the ground, but it’s not nearly as ominous when viewed from the extremely clear, dry air at high altitude. The color and darkness of the shadowy hump has not been altered in the photo – that’s exactly what it looked like. Its fuzzy appearance is caused by the atmosphere itself, which softens out the shadow’s edge. This same shadow – cast across a much greater distance – cuts across the moon during a lunar eclipse and looks similarly woolly.

You can see Earth’s shadow from the ground anytime it’s clear around sunset or sunrise. Watch for a gray-purple band to appear in the eastern sky opposite the sun at sunset (or in the west at sunrise) for up to 30 minutes before fading away in the darkening sky. Because the shadow spans nearly 180 degrees with its highest point directly opposite the sun, you’ll get a visceral sense for how huge our planet is.

View of Las Vegas, Nevada moments before touchdown. The city spans 136 square miles (352 sq. km). It’s located in a wide, flat valley between mountains. Credit: Bob King

Maybe the craziest sight of all was seeing a gigantic city in the middle of the desert. As the plane descended, red, green and blue fireworks shot up like evanescent flowers everywhere across town.

While we’re all familiar with the Hollywood stars that frequent the city’s many casinos, I was thrilled to discover some actual stars – or at least their names – on city street signs.

Star-inspired signage in Las Vegas. Aldebaran is the brightest star in the constellation Taurus the Bull; Polaris is also known as the North Star. Credit: Bob King

Sure, there’s Mel Torme Way and Frank Sinatra Drive, but the astronomically-inclined will smile wide when they turn down Aldebaran and Polaris Avenues. My daughter Katherine, who I’d come to visit, graciously parked the car so I could get a few pictures.

You couldn’t miss Upheaval Dome in Canyonlands National Park in southern Utah from the air. This striking 3.4 mile (5.5 km) wide impact crater was created 60 million years ago when a large meteoroid struck the Earth. Credit: Bob King

On the return trip, I’d hoped we pass near enough Meteor Crater in Arizona but our trajectory lay well to the north. As I followed the looping Green River from canyon to canyon an entirely different and unexpected crater crept into view from beneath the plane’s right wing – Upheaval Dome!

Younger sandstones form the outer rings of this belly button-shaped structure with older rocks heaped into a central peak on the crater’s floor. Originally thought to be a salt dome, shocked quarts and impactites found at the Dome in recent times clinch its extraterrestrial origin.

The waxing gibbous moon on July 7, 2014 above sunlit clouds. I didn’t tone the photo, allowing you to see that the clouds are considerably brighter than the moon. Credit: Bob King

Last but not least, the ever present gibbous moon shown hard and white against the super-blue sky. White, that is, until you compared it with the sunlit clouds below. They glowed far brighter, a sign that they reflect more light than the moon. Cumulus clouds have an albedo, a measure of the light reflected back by an object, of around 90%. The moon? Only 12%.

Of course I didn’t travel to the West just to stare out a window, but it was a wonderful way to pass the time while captive aboard a plane. Lots of educational rubbernecking without having to keep your hands on the steering wheel.

 

Rocky moon meets the ringed planet tonight

Look to the waxing gibbous moon tonight July 7 and you’ll see the planet Saturn about 1 degree above it. This map shows the sky around 10 o’clock local time. Stellarium

Forgive this ultra-brief appearance, but I’ve been exploring a virtually unknown astronomical paradise the past few days – Las Vegas! Although it seems incongruous, given Vegas’ image, the Las Vegas Astronomical Society has a very active presence here.

A recent photo posted by the Cassini spacecraft photo group shows Saturn’s magnificent rings, polar vortex and the jet stream-created polar hexagon. The hexagon, which is wider than 2 Earths, forms a six-lobed, stationary wave that wraps around the north polar regions at a latitude of roughly 77 degrees North. Credit: NASA/JPL-Caltech

The group planned a public outing for the Mars-moon conjunction on July 5 but were clouded out. Maybe tonight their members will get a clear sky for the Saturn-moon conjunction. I’ll be in a plane at 35,000 feet for the event crossing my fingers I get a window seat on the ‘right’ side.

Giant cave found on Mars

A beautifully conical crater pit divots the flank of ancient volcano Pavonis Mons on Mars. This digital terrain model is color coded for elevation with red for higher terrain and blue lower. Click to enlarge. Credit: NASA/JPL/University of Arizona

Caves are nothing new to the Red Planet, but a recent photo taken by NASA’s Mars Reconnaissance Orbiter (MRO) reveals a particularly large example on the flanks of the shield volcano Pavonis Mons.

Highest resolution image of the crater pit cropped and enhanced so you can see the opening at the bottom and a hint of the debris pile. Credit: NASA/JPL/University of Arizona

The walls of the pit are very steep –  if they were any steeper, debris would crumble off the walls and roll down through the hole at the crater’s base. Material that once filled the pit drained down the walls to form a pile of debris in a subterranean chamber below. The top of this debris pile can be seen through the opening about 92 feet (28 meters) farther down, although only a hint of it appears in these photographs.

An approximate cross-section of the pit showing the tall pile of rock and soil on the floor of a possible lava tube cavern hidden beneath the extinct volcano Pavonis Mons. Credit: Bob King

Based on a digital model of the ancient volcano’s terrain, scientists can estimate how much material was once in the pit and how big the pile below must be. The results are amazing – a huge hill of soil and rocks some 203 feet (62 meters) tall stands below the opening in the crater’s floor. Given that the top of this pile is 92 feet below the rim of the central hole, this tells us that the empty cavity was once 295 feet deep (90 meters) deep, prior to collapse and infilling.

Natural light view of the crater pit and its central opening to a cavern below. Credit: NASA/JPL/University of Arizona

Only a few caves on Earth are this deep. Most of those are created when water dissolves limestone. Limestone remains elusive on Mars, so planetary astronomers look to lava tubes as the most likely source of the subterranean cavern beneath the pit.

A skylight over a lava tube still coursing with lava on Kilauea in Hawaii. Credit: Martin Ruzek, USGS Hawaiian Volcano Observatory

Most Martian volcanoes are built up from multiple lava flows pouring down their flanks eruption after eruption. Sometimes the surface lavas cool and solidify to form a roof over lavas that continue to flow in underground lava tubes.

As the tubes drain, they can leave empty caverns – caves as it were. Sections of the roof can later collapse forming openings into an underground network of skylights.

Perhaps that’s what were seeing here – a window into the past when lava coursed across the thickening slopes of Pavonis Mons. One wonders whether geothermal springs might still bubble and trickle within the cave’s recesses. Could thermophilic (heat-loving) bacteria have evolved on Mars as they did on Earth and gained a foothold there? And might their descendants still be holed up as the rest of the planet became a desert sterilized by ultraviolet light from the sun?  In my crystal ball I see future mini-drone missions to Martian caves followed by visits from astronauts.

Maybe someday we’ll see what’s up down that hole.

Rosetta spies a spinning comet!

Comet 67P/Churyumov-Geasimenko rotating on 27-28 June 2014. If you look closely, you can see the comet’s not quite spherical. Credits: ESA/Rosetta/MPS for OSIRIS Team

Look at that baby spin. Comet 67P/Churyumov-Gerasimenko covers only 4 pixels in this movie but you can see a shape emerging even at this level of resolution. The ‘era of the blip’ is over!

In this smaller version of the video, you can see the comet’s rotation and shape more clearly. Credit: ESA

The movie’s composited from 36 still images taken on June 27-28 from a distance of 53,438 miles (86,000 km) and shows the comet nucleus spinning at the rate of once every 12.4 hours. Yesterday the Rosetta spacecraft pulled to within 26,718 miles (43,000 km) of 67P; by Sunday it will be as far from the comet as you and I are from the geostationary belt of Earth-orbiting satellites – a mere 22,370 miles.

Comet 67P/C-G appears rather fuzzy in the movie and seems to cover a larger area just two by two pixels. This is due to the physical effects of the way light is spread inside the imaging system and is not associated with the comet displaying a coma. The effect will disappear in the next two weeks when the images swell to 20 by 20 pixels and larger.

Go, Rosetta, go!