Max Planck was in a bad way. The German physicist was the leader in the field of quantum theory – understanding the universe on the tiniest of scales. As World War II in Europe ground to its end, though, the 87-year-old scientist and his wife were hiding in a one-room farmhouse. Germany had surrendered, and desperate soldiers were scavenging through the countryside. At the same time, the Soviet army was approaching from the east, killing or mistreating its prisoners. On the other side of the Elbe River from the farmhouse, an American soldier heard rumors that Planck was close by. Gerard Kuiper was a researcher with the McDonald and Yerkes observatories. As part of his wartime duties, he’d taught celestial navigation and worked on radar. Posted to Europe, he was part of a team that assessed the progress of Germany’s atom-bomb effort. 75 years ago today, Kuiper commandeered a Jeep and a couple of troops and headed across the Elbe, where the American advance had stopped. Kuiper found Planck and his wife at the farmhouse. They hopped in the Jeep and dodged Russian patrols – an excruciating journey for Planck, who suffered severe back pain. They returned to the American lines safely. Planck was taken to a hospital, where he recovered enough to resume his research. Kuiper returned to the U.S., and spent 10 years as director of McDonald and Yerkes – after his rescue of one of the giants of 20th-century science. Script by Damond Benningfield
Father Maximilian Hell had received an offer he couldn’t refuse. King Christian VII of Denmark and Norway had invited him to lead an expedition to observe a transit of Venus across the Sun in 1769. Hell had already declined a couple of other offers. But this one was too good to pass up. So he began preparing for one of his top accomplishments – and biggest controversies. Hell was born 300 years ago today, in modern-day Hungary. His father was chief engineer for the local mines, so science and math were a constant part of his upbringing. After he joined the Jesuit order, the queen of Austria and Hungary appointed him astronomer royal. He built a new observatory, in Vienna, and directed it for most of the rest of his life. His transit expedition took him to a small island off the coast of Norway. He took three telescopes, two clocks, and a raft of other instruments. The goal was to measure the timing of Venus’s passage across the Sun. By combining observations from different locations on Earth, astronomers hoped to calculate the exact distance to the Sun. Hell made good observations of the transit. But he didn’t report them to other scientists for many months. That raised suspicions that he’d changed them to match those of others. The controversy continued until the late 1800s, when a top astronomer found that Hell’s reports were genuine – confirming Father Hell’s status as one of the leading astronomers of the 18th century. Script by Damond Benningfield
Most of the stars in the Milky Way Galaxy move at speeds that depend on how far they are from the galaxy’s heart. But some stars strike out on their own. They can zip along many times faster than the others — and in all different directions. Most of these stars move at up a few hundred thousand miles per hour relative to the stars around them. The fastest tops out at about four million miles per hour. Some of these stars are moving fast enough to leave the Milky Way behind — and streak into the space between galaxies. Astronomers have identified at least three ways to give a star such a strong kick. One is an encounter with the supermassive black hole at the center of the Milky Way. It’s four million times the mass of the Sun, with a powerful gravitational pull. As a binary star system approaches it, the black hole may grab one of the stars and give the other a boost away from it. A second way is a bit of gravitational acrobatics among three or more stars. That can juggle the orbits of some of the stars, but shove one of them away from the others. And the third way involves a stellar explosion. When a massive star explodes as a supernova, it loses most of its mass. That means its gravity isn’t as strong. So a companion star could zip off in a straight line — away from the explosion. And the shockwave from the explosion could add to the kick — perhaps punting the companion out of the galaxy. Script by Damond Benningfield
Walking across the largest moon of Mars might be quite a jolt. Mars would spread out just 3800 miles away. A strong jump could push you out into space. And the moon’s nightside might create electric shocks — not enough to hurt a person, but enough to damage equipment. Phobos looks like a potato with a bite nipped off one end. On average, it’s about 14 miles in diameter — the size of a small city. Escape velocity from the little moon is just 25 miles per hour — less than the top speed of sprinter Usain Bolt. That low gravitational pull could someday make Phobos a good spot for a base — it would take little fuel to land and take off. But a trek across Phobos could create an electric charge. A study a couple of years ago found that a strong charge may build up on the little moon’s nightside — a result of the solar wind. The wind contains particles with both positive and negative electric charges. But more negative particles may hit the nightside than the dayside. So anyone who walks across the nightside might build up a static charge — like walking across a carpet in your socks. Touching any metal could then cause a discharge — perhaps strong enough to damage scientific instruments or other equipment — a bit of a “jolt” on this odd little moon. Mars is near our own Moon the next couple of mornings. The planet looks like a fairly bright orange star. It’s to the left of the Moon at first light tomorrow, and a bit closer above the Moon on Friday. Script by Damond Benningfield
Big planets do things in a big way. Consider Saturn, the second-largest planet in the solar system. A couple of years ago, astronomers tracked four storms in its northern hemisphere. They weren’t like other storms on the planet. They were bigger than the average storm, but smaller than the giants that break out every few decades — they were right in the middle. This being a giant planet, though, “mid-sized” is a whole different concept: The storms ranged from 2500 to 5,000 miles long, and lasted for up to seven months. Saturn’s outer atmosphere is hundreds of miles thick. It’s stretched into planet-circling bands by Saturn’s high-speed rotation. The bands are colored in shades of yellow, white, and tan. Occasionally, a storm breaks out — an explosion of water clouds driven by heat from inside Saturn. Most of the storms are hundreds of miles across. Every once in a while, though, a monster breaks out. It can stretch most of the way around the planet — tens of thousands of miles. A recent study says the new storms could have been trying to build to giant proportions. But a monster storm a decade ago could have robbed their part of the atmosphere of energy — leaving them at mid-sized proportions. Saturn stands to the upper right of the Moon at first light tomorrow, and looks like a bright star. The even brighter planet Jupiter is to the right of Saturn. And Mars is well to the left of the Moon. More about that tomorrow. Script by Damond Benningfield
Ancient skywatchers gave the planets personalities. Jupiter, for example, represented the king of the gods of Olympus, with all the qualities that suggests — strength and courage, among others. If the modern world associated the planets with heroic beings, it might still be Olympians — but of the athletic kind. Mercury might be a sprinter, and Saturn a marathoner. And Jupiter would be king of the shot-put. Jupiter is the giant of the solar system — it’s more massive than all the other planets put together. That gives it a powerful gravitational field, which has a big influence on the space around it. When the solar system was young, it was filled with billions of small chunks of rock and ice known as planetesimals — the building blocks of the planets. Jupiter’s gravity ejected many of them from the solar system, into deep space. Jupiter also pushed around planetesimals in a broad band between Jupiter and Mars, preventing them from forming a planet. Today, that band is the asteroid belt. Jupiter continues to push around smaller bodies even now. Encounters with comets or asteroids can shove them into different orbits. It can even kick them out of the solar system entirely — long-distance shot-puts for a true Olympian. Jupiter rises quite close to the Moon in the wee hours of the morning, and is above the Moon at first light. It looks like a brilliant star. The planet Saturn is nearby, and we’ll have more about that tomorrow. Script by Damond Benningfield
The bright Moon is getting ready to run a gauntlet in the pre-dawn sky – a gauntlet of three planets. The planets align to the left of the Moon at first light tomorrow. The Moon will move past them over the following mornings. The Moon is in its waning gibbous phase for the next few days. That means that sunlight illuminates more than half of the hemisphere that faces our way, but not the whole hemisphere. The word “gibbous” comes from a Latin word that means “hump.” It indicates that the Moon looks like it has a hump on its back. Over the next few days, though, the hump will be getting smaller – where the “waning” part of the title comes in. Tomorrow, the Moon will be about 80 percent full – the Sun will light up 80 percent of the lunar disk. For the following few days, though, that fraction will drop by about 10 percent per day. By Friday, only about 40 percent will be in sunlight. At that point, the Moon will be in its waning crescent phase. The crescent will grow thinner until the Moon disappears in the dawn twilight. Watch the Moon as it grows thinner over the next few mornings – and passes by a beautiful array of planets. The brightest of the three worlds is Jupiter, the brightest object in the sky at that time other than the Moon. It’s to the left of the Moon tomorrow. Saturn stands close to the left of Jupiter, with orange Mars a good distance to their lower left. We’ll have more about the Moon and Jupiter tomorrow. Script by Damond Benningfield
The sky offers two north poles. One is the celestial pole. It’s marked by Polaris, the North Star. Earth’s axis aims toward Polaris, so all the stars appear to rotate around it. And the star is in the same position in the sky all day and night — marking due north. The north galactic pole moves around the sky. It stays in the same constellation, but the constellation turns around Polaris, so the pole moves, too. This pole is based on the alignment of our home galaxy, the Milky Way. Astronomers have devised a set of galactic coordinates. The “east-west” line is marked by the plane of the galaxy’s disk. You can get a rough idea of the plane by looking at the hazy band of light that outlines the Milky Way. A lane down the middle of that band generally looks darker than the rest of it — a pretty good marker of the galactic plane. The east-west coordinates are centered on the heart of the galaxy, in Sagittarius — a galactic longitude of zero. That’s also the starting point for galactic latitude — the position north or south of the plane. The point 90 degrees north marks the north pole. It’s in Coma Berenices. Right now, it’s high in the southeast at nightfall, above the bright yellow-orange star Arcturus. Since we’re looking away from the Milky Way’s disk, that region offers an unobstructed view beyond the Milky Way. In fact, it’s home to one of the most impressive galaxy clusters around — spreading out near the north galactic pole. Script by Damond Benningfield
It’s big. It’s bright. And it’s doomed. Antares is one of the most impressive stars in the galaxy. It’s at least 15 times as massive as the Sun, hundreds of times wider, and tens of thousands of times brighter. But that flashiness comes at a price. The star’s lifetime will be measured in millions of years versus billions of years for more sedate stars like the Sun. When that lifetime is up, the star’s core will collapse, while its outer layers will blast into space as a supernova. The blast will push a mixture of chemical elements out into the galaxy — elements created in the star’s core during its short lifetime, or in the surrounding layers of gas during the explosion. The collapsed core will most likely form a neutron star — a ball a couple of times the mass of the Sun but only a few miles in diameter. Most young neutron stars spin rapidly, beaming out pulses of energy, so they’re also known as pulsars. And they generate magnetic fields that can be millions of times stronger than Earth’s. That gives them yet another designation: magnetars. Astronomers don’t know all the signs that herald an impending supernova, so they can’t be sure just when Antares will explode. All they know for sure is that it’s likely to happen within the next million years or so — and it could happen as early as tonight. Look for bright orange Antares rising to the right of the Moon around 11 o’clock, and leading the Moon across the sky later on. Script by Damond Benningfield
Vanguard 1 has been orbiting Earth for more than 60 years — longer than any other spacecraft. And it’s expected to stay in orbit until late in the 22nd century. Just about every other spacecraft is expected to crash to Earth much sooner. Most will burn up in the atmosphere, or splash into the oceans. But a few will hit land, perhaps harming property or people. The odds of such an impact are getting better all the time. More than 9,000 satellites have been sent into orbit, and about half are still there. And the number of satellites is expected to rise dramatically in the next few years. There’s lots of other stuff up there, too — debris from exploded rocket stages, for example. These projectiles could damage or destroy spacecraft — creating more pieces of debris that could fall to Earth. Some satellites are targeted to splash into a lonely region of the Pacific Ocean. But controlled re-entry adds to a mission’s cost. Most commercial satellites are insured against the possibility that they’ll cause damage or injury when they hit the ground. And satellite operators are looking at ways to make it more likely that future craft will completely burn up in the atmosphere. But it’ll take a while to implement new designs. So far, only six people are known to have been hurt by falling debris. As both Earth’s surface and Earth orbit get more crowded, though, we could see more such incidents in the decades ahead. Script by Damond Benningfield
At the end of last year, a couple of thousand working satellites were orbiting Earth — watching the weather, tracking people and equipment, and studying the universe. Over the next few years, though, the number could increase by a factor of seven or eight. That could be good for business, but not so good for astronomy. From the start of the Space Age, in late 1957, through last year, the world had launched about 9,000 satellites. Most of them have either stopped working or fallen back to Earth. But two companies are ready to fill low Earth orbit with many more. SpaceX and OneWeb are launching thousands of small satellites into low orbits to provide high-speed internet service. OneWeb could launch a couple of thousand, while SpaceX has announced plans to launch up to 12,000. For astronomy, though, that’s a problem. As the satellites pass across the sky at certain times of night, they reflect the Sun’s rays. So they create bright streaks of light on any pictures astronomers might be taking. In February, the International Astronomical Union said it considers the satellites “worrisome.” The constellations of satellites, it said, “will have a negative impact on the progress of ground-based astronomy.” SpaceX, which has already launched hundreds of satellites, is testing a new coating to make the craft darker. Even so, the view of the universe is likely to get a lot messier in the years ahead. More about satellites tomorrow. Script by Damond Benningfield
The two brightest objects in the night bracket the sky as darkness falls this evening. The almost-full Moon is in the southeast, with Venus, the “evening star,” setting half way around the sky, in the west-northwest. About the only thing that can challenge the Moon’s brightness is a bolide — the brightest type of meteor. Such flashes are quite rare, though. One other nightlight can at least challenge Venus, though — the International Space Station. It’s the biggest spacecraft ever built, so it’s especially brilliant — as bright as Venus. Thousands of satellites are in orbit right now. Most of them are too small, too far, or too dark to see. But some of them are visible as they move across the sky. They’re in sight only for a while after sunset or before sunrise. They’re high enough then to be in sunlight, so they reflect that light down to Earth. But it’s dark at the surface, so we see them streaking across the sky. The space station is the biggest and brightest. Hubble Space Telescope is a bright target, too. And so are the Iridium satellites — communication satellites in low orbits. They flare brightly when they catch the sunlight just right. A couple of companies are beginning campaigns to launch thousands of new satellites. They, too, may be pretty bright — especially as they climb to their final orbits. That might be fun to watch — but not fun for astronomers. We’ll have more about that tomorrow. Script by Damond Benningfield
There are quite a few celebrations of space at this time of year. Friday, for example, was International Space Day, while Saturday was Astronomy Day. And tomorrow is National Astronaut Day. The date was chosen because the first American astronaut, Alan Shepard, rocketed into space on May 5th of 1961. And today celebrates some fictional accomplishments in space. It’s Star Wars Day. May the Fourth was picked as a pun on the line “may the force be with you.” Star Wars Day started in Toronto almost a decade ago, and caught on around the world. In 2012, Boris Johnson — now prime minister of the United Kingdom — celebrated his election as mayor of London on Star Wars Day: JOHNSON: Thank you very, very much everybody, and may the fourth be with you! In 2014, an astronaut beamed greetings from the International Space Station. And minor league baseball teams have worn Star Wars-themed uniforms on the date. Some German astronomers may celebrate at their own version of R2-D2. In late 2018, Hubert Zitt and colleagues at Zweibrück Observatory repainted a 15-foot telescope dome to look like the droid. It became famous when Luke Skywalker himself — actor Mark Hamill — tweeted about it a few months later. Of course, you don’t have to wait for specific dates to celebrate the universe and space exploration. Look up at the sky on any night, read a book, check out the latest pictures from Mars — or, yes, watch a movie. And may the fourth be with you. Script by Damond Benningfield
A modest meteor shower is at its best the next couple of nights. At its peak, the Eta Aquarid shower might produce a couple of dozen meteors per hour. But the Moon is almost full now, so it’s in the sky until shortly before dawn. Its light will wash out all but a few of the “shooting stars.” The moonlight demonstrates the importance of dark skies for viewing the subtleties of the night sky. Extra light knocks out our view not only of faint meteors, but of the Milky Way, the northern lights, and many other faint but beautiful sights. We can’t do much about the bright Moon. But we can do something about artificial lights — the fixtures that light our streets, buildings, and homes. Fixtures that shine much of their light into the sky aren’t very efficient. They don’t do a good job of lighting the ground, which is what most of them are supposed to do. And since they’re wasting a lot of their light, they’re also wasting energy. What’s more, the light in the sky can distract migrating birds, sea turtles, and other creatures. It can even create health problems for people. Some cities and counties have banned inefficient outdoor lights. But individuals can help, too. Make sure that any outdoor lights are shining down, not up, and that they’re the right color — blue light is worse than warmer colors. That can help keep the skies dark, enhancing the view of meteor showers and other wonders — at least when the Moon is out of sight. Script by Damond Benningfield
Venus, the “evening star,” flirts with the tip of one of the bull’s horns for the next few weeks. The tip is represented by the star El Nath — a name that means “the butting one.” This evening, it’s a couple of degrees above Venus. Venus will draw a little closer over the coming nights, but won’t quite catch up to it. They’ll stay within a couple of degrees of each other, though, through the middle of the month. El Nath is about 135 light-years away. Perhaps more interesting, though, is what lies beyond it. El Nath is the closest bright star to the galactic anti-center — the point exactly opposite the center of the Milky Way Galaxy. The center is in Sagittarius, which will be in good view in a couple of months. That region of the galaxy is densely packed — stars and gas clouds galore. But the anti-center faces the galaxy’s poorly populated outer regions. So the view of the Milky Way in that direction is thin — you need really dark skies to make it out. The edge of the Milky Way’s disk is far beyond El Nath. Just how far isn’t certain, though. We’re about 27,000 light-years from the center of the galaxy. And most studies say it’s about 50,000 light-years from the center to the edge. That would put the edge about 25,000 light-years away. Some recent work, though, has found a few straggler stars even farther out. Either way, it’s a long haul. Just head for El Nath and keep on going — to the edge of the galaxy. Script by Damond Benningfield
For lunar colonies, nothing will be more important than water — and not just for drinking. It’ll supply oxygen for breathing, and oxygen and hydrogen to power their rockets. But there’s no liquid water anywhere on the Moon. There is a large amount of frozen water, but most of it is buried in craters at the poles. NASA’s getting ready to test out some electronic “noses” designed to sniff out that water. They’ll be carried to the Moon on a pair of landers next year. Last year, the Space Agency selected three companies to land scientific instruments on the Moon, although one of them quickly dropped out. And early this year, it picked 16 experiments for the probes to carry. Most of the experiments are designed to help plan for astronauts to land on the Moon in a few years. Some will measure the level of radiation at the lunar surface, for example. Others will study how the landers change the surface. And one will test new solar cells that will power future missions. Several of the instruments will look for evidence of water and other compounds that astronauts might be able to use, such as methane and carbon dioxide. The instruments will “sniff” out tiny amounts of these materials wafting just above the surface. The experiments will pioneer ways for explorers to “live off the land” — on the surface of the Moon. Look for the Moon high in the sky at nightfall. Regulus, the star that marks the heart of the lion, stands just below it. Script by Damond Benningfield
Hubble Space Telescope entered orbit 30 years ago last week. LAUNCH CONTROL: 3, 2, 1, and liftoff of the space shuttle Discovery with the Hubble Space Telescope, our window on the universe. And it’s still going today. Over the decades, it’s provided new insights into stars and galaxies, the age of the universe, and even the future of the universe. But it’s needed some help. ENDEAVOUR: Endeavour has a firm handshake with Mr. Hubble’s Telescope. Five crews of shuttle astronauts upgraded its instruments and repaired or replaced ailing systems — the last in 2009. LAUNCH CONTROL: Liftoff of space shuttle Atlantis on the final visit to enhance the vision of Hubble. A service call is unusual for missions of exploration, though. Engineers can send commands to overcome some problems, and they can upgrade the computer software, but major failures don’t get fixed. Even so, several explorers have operated as long as Hubble has — or even longer. The champions are Voyagers 1 and 2. They were launched in 1977 to explore the outer solar system. They’ve left the solar system behind — they’re studying interstellar space. They’re losing power, so most of their instruments have been turned off. And they have occasional problems. Voyager 2, for example, went into “safe mode” in late January. It saw that something was wrong, then shut down and waited to hear from Earth. Engineers sent commands to get Voyager started again — keeping this aging explorer going for a little while longer. Script by Damond Benningfield
It’s definitely not Kansas. But it is home to one of the state’s favorite characters, Dorothy Gale. Captain Nemo is there, too. And so are Arthur C. Clarke and Stanley Kubrick – the creators of “2001: A Space Odyssey.” Charon is the largest moon of Pluto. It’s about 750 miles in diameter – a third the size of our own moon. The New Horizons mission gave us our only close look at it in 2015. It found that Charon has a dark orange “beanie” cap – ices that wafted off the surface of Pluto. It has a thousand-mile “belt” of canyons around its equator. And several big impact craters are carved in its icy surface. The International Astronomical Union has named about a dozen of those features. All of the names are related to exploration – places, writers, or vessels connected with real or imagined lands. One of the canyons, for example, is Argo Chasma. It’s named for the ship that carried Jason and the Argonauts. It has some of the tallest cliffs in the solar system – up to six miles high. The “beanie cap” is called Mordor Macula, after a character from “Lord of the Rings.” Gases from Pluto form a fresh coating of ice at the north pole. The ice turns orange when in the sunlight. And a mountain is named for Octavia Butler, a science-fiction author. Many other features are waiting to be named. All of the names will follow the same theme – honoring the spirit of exploration. We’ll talk about some current explorers tomorrow. Script by Damond Benningfield
A “mini-Milky Way” arcs low across the south on spring evenings. It’s a galaxy that probably resembles the Milky Way, but it’s only half as big. Messier 83 is a beautiful spiral that we view face-on. It’s only about 15 million light-years away, so the view is especially good. The galaxy has a “bar” of stars across its middle, with spiral arms extending from the ends of the bar. That appearance has earned it a nickname: the Southern Pinwheel. Although it’s much smaller and less massive than the Milky Way, M83 is much busier. It’s giving birth to many new stars. Astronomers have discovered about 3,000 star clusters in the galaxy, many of which are less than five million years old. They’ve also discovered the remnants of about 300 massive stars that exploded fairly recently. All that activity may be the result of a near-collision with another galaxy. The galaxies may have passed near each other a billion years ago. The gravity of each galaxy squeezed clouds of gas and dust in the other galaxy. That caused the clouds to collapse and give birth to new stars — a process that continues today. M83 is in Hydra, the water-snake. It climbs into view a couple of hours after sunset, and is low in the south around midnight. The galaxy is too faint to see with the eye alone. Binoculars reveal a small, hazy circle of light. Telescopes reveal more detail — a beautiful galaxy pinwheeling across the southern sky. Script by Damond Benningfield
From the globular star cluster Messier 53, the view would be spectacular. The cluster floats high above the disk of the Milky Way Galaxy. So the entire galaxy would spread out below it — from the graceful spiral arms to the star-packed core. M53 orbits the core, so it’s a member of the galaxy. But that might not always have been the case. Studies have suggested that it was born in another galaxy — perhaps as the galaxy’s core. Billions of years ago, that galaxy was pulled in by the Milky Way’s powerful gravity. Most of its stars were stripped away and absorbed by the Milky Way’s disk. But M53 stayed in the halo — a vast region that surrounds the disk. Today, the cluster is perhaps 60,000 light-years from the core — and about the same distance from Earth. But its orbit carries it up to twice as far from the galaxy’s heart. The view inside the cluster would be spectacular as well. M53 contains hundreds of thousands of stars. Most of them are packed into a ball only a few dozen light-years across. So the night sky of a star inside the system would glow with many more bright stars than our own sky. That would make the view from M53 doubly impressive — stars all around, and the Milky Way below. Messier 53 is in the constellation Coma Berenices. The cluster is well up in the east at nightfall, and is an easy target for binoculars. It’s easier to see by around midnight, as the Moon drops from view. Script by Damond Benningfield