First up is Earth’s motion around the Sun. Our planet’s average orbital speed is about 66,600 miles per hour. At that speed, it takes exactly one year for Earth to make one full turn.

The Sun is moving as well, and it’s taking Earth and the rest of the solar system along for the ride. The Sun is about 27,000 light-years from the center of the Milky Way Galaxy. It circles around that center at almost 500,000 miles per hour. The galaxy is so huge, however, that it takes about 230 million years to complete one orbit.

And that’s not the fastest motion we’re experiencing. The Milky Way belongs to a small cluster of galaxies, the Local Group. The group is being pulled toward the Virgo Cluster, which contains thousands of galaxies. And the Local Group, Virgo Cluster, and much more are being pulled in by the gravity of the Great Attractor – the center of an enormous collection of galaxies and dark matter. The Milky Way is speeding toward it at more than 1.3 million miles per hour.

So while the ground beneath your feet feels steady, keep in mind that it’s on the move – tugged by the Sun, the galaxy, the Great Attractor – and perhaps even more.

Script by Damond Benningfield

The element itself is created in some of the most violent events in the universe. In fact, so were almost all of the heaviest elements – anything more substantial than iron.

The elements are forged in the rapid neutron-capture process. “Seed” elements are slammed by huge amounts of neutrons – the bits of an atomic nucleus with no electric charge. That builds heavier elements, including gold, silver, uranium – and iodine.

Lighter elements are forged in the hearts of stars. More-massive stars create heavier elements. But they can’t make anything heavier than iron. The element-making process shuts down, and the star explodes. The blast can produce huge numbers of neutrons, which are sent flying at high speed. They ram into the debris, creating heavier elements.

But not all exploding stars produce the right conditions to make heavier elements – especially the heaviest of all. Those elements can be formed when two ultra-dense stellar corpses ram together. The merger splatters the region with neutrons. They can forge enough heavy elements to make many planets as massive as Earth.

Iodine probably is made by both types of events, which sprinkle this life-giving element throughout the cosmos.

Script by Damond Benningfield

Comet C/2025 R3 PanStarrs was discovered in September. It probably is falling inward from the Oort Cloud. That’s a huge reservoir of balls of rock and ice that enwraps the solar system. This one might have been nudged inward by the gravity of a passing star.

Objects in the Oort Cloud were born when the planets were taking shape. Jupiter’s gravity hurled them far into space. In the cold and dark, those bodies have changed very little for billions of years.

As PanStarrs approaches the Sun, some of its ice vaporizes. That releases bits of rock and dirt. The debris forms a cloud around the comet, plus a long, glowing tail. Studying this material provides insights into the birth of Earth and the other planets.

The comet will pass closest to the Sun on April 20th. It’ll be closest to Earth a week later – 44 million miles away. If it survives the Sun’s heat, it then will rocket back into deep space, not to return for thousands of years, if ever.

PanStarrs is low in the east before and during dawn. Because we record in advance, we can’t tell you how bright it looks, or how bright it’ll get. We can tell you that it will zip across the Great Square of Pegasus next week, then move into Pisces. By then, it will appear so close to the Sun that it’ll be tough to spot, with or without optical aid.

Script by Damond Benningfield

A space telescope has been keeping a close eye on the aftermath of that event for the past 25 years. That’s revealed a lot about the supernova and the environment around it.

The supernova flared to life when a stellar corpse known as a white dwarf tipped above its weight limit. The star either stole gas from a companion star, or it merged with another white dwarf. Either way, the star was blasted to bits. The explosion expelled a huge cloud of debris – a nebula that today spans about a light-year. It’s extremely hot, so it produces a lot of X-rays.

Chandra X-Ray Observatory has taken many looks at the nebula. It’s found that one side of it is expanding at about two percent of the speed of light. The opposite side is moving only one-third that fast. The slower side is also hotter. That’s because it’s running into more gas and dust around the nebula.

Chandra will keep an eye on the nebula for as long as it can – telling us much more about the violent death of a star. The nebula is at the southern edge of Ophiuchus. At dawn tomorrow, it’s to the upper right of the Moon.

Script by Damond Benningfield

Predicting such storms can save a lot of grief. But better predictions require a better understanding of the Sun, Earth’s magnetic field, and how they interact. A mission scheduled for launch as early as this week should help.

SMILE is a joint project of Europe and China. The craft will orbit up to 75,000 miles from Earth. From that high perch, it’ll be able to see Earth’s magnetopause – the zone where the solar wind rams into Earth’s magnetic field. It will monitor that zone for up to 40 hours at a time – far longer than any glimpses we’ve had before.

Earth’s magnetic field deflects most of the particles in the solar wind. But some of them get through. They create the auroras – the colorful northern and southern lights.

Powerful storms on the Sun blast out huge amounts of particles. They can overwhelm the magnetic field, creating intense bouts of “space weather.” Among other effects, that causes especially intense auroras, which can appear in regions where they’re seldom seen. SMILE will watch the auroras to see how they change with the level of solar activity.

SMILE’s observations will tell us a lot more about how Earth and the Sun get along – improving our ability to protect ourselves from solar storms.

Script by Damond Benningfield

Antares is a monster. It’s roughly a dozen times the mass of the Sun, and 700 times the Sun’s diameter. So its average density is less than one-billionth of the Sun’s. And most of its mass is concentrated deep in the core, which is where the star generates its energy.

That means the outer layers are extremely thin – so thin that it’s tough to define the surface – it blends into the background.

The surface temperature of Antares is about 6100 degrees Fahrenheit, compared to 10 thousand degrees for the Sun. We’ve already built a probe that can approach to within a few million miles of the Sun. It has a shield that can withstand temperatures of about 2500 degrees. A plunge into Antares would be hotter, but building a shield to take the heat doesn’t seem impossible – providing a way to get an up-close look at this monster star.

Antares climbs into good view by 1 or 1:30 a.m. It’s close to the lower left of the Moon as they rise, with the Moon inching closer to the star before dawn.

Script by Damond Benningfield

There’s not much to see in Monoceros with the eye alone. But telescopes reveal a bounty of beautiful sights. And Beta Monocerotis straddles both domains. It’s faintly visible to the unaided eye as one of the unicorn’s two brightest stars. But to see the same beauty that Herschel did, you need a telescope. That view reveals three stars, not one, all with a fetching blue-white color.

The color comes from the temperatures of the stars – their surfaces are many thousands of degrees hotter than the Sun’s. And all three stars are much more massive than the Sun. That revs up the nuclear reactions in their cores, which is what makes them so hot. It also makes the stars extremely bright – as much as 3200 times as bright as the Sun. So the stars are visible across 700 light-years of space.

The two faintest members of the system probably form a wide binary, with the third star orbiting around them. Combined, they make Beta Monocerotis a beautiful skywatching sight – a vision in blue for an early-spring night.

Script by Damond Benningfield

One example is the system Gaia BH2. It consists of two known objects. But there might once have been a third object – a star that was gobbled up.

The system was discovered by Gaia, a space telescope. It revealed two objects: a black hole about nine times as massive as the Sun, and a giant star about 1.2 times the Sun’s mass. They orbit each other once every three and a half years.

Ground-based telescopes revealed the composition of the giant. Its chemistry looked like that of an ancient star.

But observations by TESS, another space telescope, suggested otherwise. The satellite measured “starquakes” on the surface of the giant star. Sound waves bounce around inside the star and back to the surface. So just as an earthquake tells us what’s happening below the surface of Earth, a starquake tells us what’s happening deep inside a star.

The quakes revealed that the star spins faster than expected. That suggests it was spun up by interactions with something else. It might have swallowed debris that encircled the black hole. Or it might have swallowed another star, changing the chemistry at its surface – prematurely “aging” this giant star.

Script by Damond Benningfield

Spica is the brightest star of Virgo. It rises just above the Moon early this evening.

The system consists of two big, heavy stars. The primary star, Spica A, is about 10 times the mass of the Sun. Spica B is about seven times the Sun’s mass. The stars are so close together that they whirl around each other once every four days.

Within a few million years, Spica A will consume all the nuclear fuel in its core. The core will collapse, probably forming a neutron star – an object up to twice the mass of the Sun, but only as big as a city. Its outer layers then will blast into space at a few percent of the speed of light – a supernova.

The companion star should survive, although it might lose some gas from its surface. But what happens next is tricky.

Supernovas sometimes explode asymmetrically – the blast can be off-centered. That can give the neutron star a big kick. And the neutron star will be only a fraction as massive as the original star. That means its gravitational grip on its companion will be much weaker. The neutron star could zip off at high speed – perhaps fast enough to escape the galaxy.

And even if that doesn’t happen, the stars are likely to move farther apart – a bigger gap between these impressive stars.

Script by Damond Benningfield

That difficulty illustrates how tough it’s been for scientists to study Mercury. It’s never in view for long – no more than a couple of hours before sunrise or after sunset. And it’s so low in the sky that we always see it through a thick layer of air, so the view is murky – like trying to make out the shapes of clouds from the bottom of a swimming pool.

In the late 1800s and the early 1900s, astronomers did make a few crude maps of Mercury’s surface. But there was a lot they couldn’t figure out. That included the length of the planet’s day. At first, it appeared that Mercury completed one turn on its axis in 88 Earth days – the same length as its year.

In the early 1960s, though, astronomers bounced radio waves off the surface. That work showed that a day lasts 59 Earth days. So Mercury completes three turns on its axis for every two orbits around the Sun – three days for every two years.

Again, look quite low in the east not long before sunrise for elusive little Mercury – a planet that’s been hard to get to know.

Script by Damond Benningfield