StarDate

Space weather could be especially stormy this year. A forecast issued late last year said the Sun’s current cycle of magnetic activity should peak sometime this year. And the peak should be a lot more intense than predicted in earlier forecasts. That could mean more problems for satellites and other technology.Space weather is powered by magnetic activity on the Sun. That activity goes through a cycle that peaks roughly every 11 years. At the peak, the Sun produces more sunspots and solar flares — bif explosions of particles and energy.As those waves pass by Earth, they can zap orbiting satellites. They also heat the outer atmosphere, increasing the drag on satellites, shortening their lifetimes. In addition, Earth’s magnetic field directs charged particles toward the surface. The particles can knock out power grids, and force airlines to re-route flights across the north polar regions. So accurate forecasts are critical for the folks who maintain those important services.The past couple of solar cycles have been especially quiet. And the current cycle was expected to follow that pattern, reaching its peak in 2025. Instead, the level of solar activity has been much higher than forecast. That suggests the current cycle will peak earlier than originally expected — sometime from January to October of this year. And the peak will be more active — revving up the intensity of space weather. Script by Damond Benningfield

Perhaps the most important number that astronomers need to know about a star is its distance. That allows them to calculate the star’s true brightness, which helps them calculate the star’s mass, its stage in life, and much more.An example is Arneb, the brightest star of Lepus, the rabbit. At nightfall, the constellation stands to the lower right of Orion, below Rigel, the star that marks the hunter’s foot.Estimates of Arneb’s distance vary by quite a bit — from as close as about 1300 light-years, to as far as about 2200. Astronomers compare the star’s distance to how bright it appears in our sky to determine its true brightness. At the lesser distance, the star would be more than three times fainter than at the greater distance. And that factors into the understanding of the star’s mass, its life cycle, and its fate.Probably the best measurement of the distance comes from Gaia, a space telescope. It’s measured the distances to roughly 1.7 billion stars. Above Earth’s atmosphere, it has a sharp view of the heavens, helping it to make more precise measurements.Gaia says that Arneb is a little more than 1900 light-years away. That means the star is roughly 10,000 times brighter than the Sun. It’s a supergiant — it’s many times the size and mass of the Sun. And it’s nearing the end of its life. In the next million years or so, it’s expected to explode as a supernova — giving Orion a real hotfoot. Script by Damond Benningfield

The Moon and the star Regulus move across the sky together tonight. Regulus is to the upper right of the Moon as they climb into good view, around 8 or 8:30.The name “Regulus” means “the little king.” But the star has many other names as well. The most commonly used is Alpha Leonis. It indicates that Regulus is the brightest star of Leo, the lion.The naming system was created by German astronomer Johannes Bayer, in 1603. He named more than 1400 stars. It was the first systematic naming system for the stars.Bayer names consist of a Greek or Latin letter, followed by the possessive form of the constellation’s name. Bayer grouped the stars in a constellation by brightness. He had to judge them with his eyes alone, so it wasn’t always easy. The brightest stars got the first letters of the Greek alphabet, so the brightest star of all was usually “alpha,” followed by “beta,” and so on. When the Greek letters were gone, Bayer used the Latin alphabet.Not every constellation followed this rule, though. In quite a few, the names were bestowed based on a star’s position in the constellation, or some other criteria.Bayer named only the stars that were visible from Germany and a short distance southward. So many stars in the far southern sky were left out. They were filled in by later astronomers — making sure that every star bright enough to see with the naked eye had its own Bayer designation. Script by Damond Benningfield

If you’re driving up the highway from Dallas to Minneapolis, you might rely on the Global Positioning System to help get you there. If GPS didn’t take the equations of Albert Einstein into account, though, you might wind up in Rapid City, or Milwaukee, or even the middle of Lake Michigan. That’s because the system’s timing would be off — an error that adds up to several miles per day. That would quickly make the system useless.The effect is known as time dilation. It comes from Albert Einstein’s theories of Relativity. They tell us that clocks tick at different rates relative to each other, depending on their speed and the gravitational pull they feel. So clocks on spacecraft appear to tick at different rates from those on Earth. An astronaut on the International Space Station, for example, ages a few millionths of a second less every day than the people on Earth.GPS satellites orbit at much higher altitudes than the space station, and their orbital speed is less. When you combine the effects, a clock on a GPS satellite gains about 38 millionths of a second per day compared to its ground-based counterparts. GPS computes locations based in part by comparing the time on different satellites. So the clocks on these satellites are adjusted to tick that much slower than the clocks on the ground. That keeps all the clocks in sync — and you on the right path to your destination. Script by Damond Benningfield

No two clocks in the universe appear to tick at exactly the same rate. That’s because no two clocks move at exactly the same speed, or feel exactly the same gravitational pull. Even two clocks on the same wall tick at slightly different rates. For those clocks, the difference is tiny — it would take longer than the age of the universe to add up to a single second. In other cases, though, the difference can be dramatic.The effect is known as time dilation. The explanation for it comes from Albert Einstein’s theories of Relativity. And as those theories tell us, it all depends on who’s looking at the clock.Special relativity says that clocks appear to move at different rates for objects moving at different speeds. Seen from Earth, the clock of a spacecraft moving at almost the speed of light would appear to tick slower than a clock on Earth. From the starship, though, its clock would move at the normal rate, while the clock on Earth would appear to move slower. Both clocks are correct. But viewed from different perspectives, they appear to tick at different rates.General relativity says the same thing applies for objects in different gravitational fields. The stronger the gravity, the slower the clock appears to tick as seen from outside the stronger field.Both effects have been confirmed by experiments. They make for some interesting science fiction. But they also apply to daily life. More about that tomorrow. Script by Damond Benningfield

ASTRONAUTS: There’s a chunk there that we can get. That’s a big fragment within this crystalline rock. Take a picture of that…Apollo 17 astronauts Gene Cernan and Jack Schmitt were chipping samples from a large boulder. It was at the base of a cliff, in a region of the Moon known as Taurus-Littrow.ASTRONAUTS: They’re very reflective, elongated crystals. It’s relatively angular inclusions. It’s about half a meter in size, and it’s a square cross section.Scientists recently got the chance to study part of one of those chips for the first time. They found that it contained the oldest piece of the Moon yet seen — 4.46 billion years old. That’s 40 million years older than any other sample yet studied. It means that the Moon formed 40 million years earlier than suggested by earlier studies.The Moon probably formed in a “Big Whack.” A planet as big as Mars rammed into the young Earth, blasting molten rock into space. Much of that material came together to form the Moon.The Apollo 17 sample contained crystals that formed when the Moon cooled and solidified. Because it’s the oldest sample yet seen, it sets a minimum age for the Moon. It tells us that the Moon formed no more than 110 million years after the birth of the solar system — helping scientists time the Big Whack.The Moon is in the east at nightfall. Pollux and Castor, the twins of Gemini, stand above it. The brighter twin, Pollux, is closer to the Moon. Script by Damond Benningfield

The earliest galaxies were a lot busier than their modern-day counterparts. They were giving birth to stars at a much faster rate. That included many stars that were especially hot and heavy. Those stars ended the cosmic “Dark Ages” — a period when the universe was dark and foggy.The Dark Ages began soon after the Big Bang. The universe was filled with a “fog” of neutral hydrogen — atoms that blocked the glow of developing stars and galaxies. But the first hot, massive stars cleared away the fog.Observations by Webb Space Telescope have allowed astronomers to see deeper into the Dark Ages than ever before. The telescope is large, and it’s above Earth’s atmosphere. The combination allows it to see the early universe more clearly than any other telescope in space or on the ground.Webb revealed early galaxies up to 50 times fainter than any ever seen before. Those observations revealed the presence of certain chemical compounds. Those compounds are produced by the strong radiation from the hot young stars. The stars are dozens of times the Sun’s mass, tens of thousands of degrees hotter, and perhaps hundreds of thousands of times brighter.Webb’s observations showed that early galaxies gave birth to these and other types of stars in giant outbursts — millions of stars at a time. The stars cleared up the fog — ending the cosmic Dark Ages.Tomorrow: looking deeper into the early days of the Moon. Script by Damond Benningfield

The most-distant objects we can see are galaxies more than 13 billion light-years away. That means we see them as they looked just a few hundred million years after the Big Bang. We know their distance because astronomers measure their cosmological redshift — an effect caused by the expansion of the universe.As the universe expands, it “stretches” the wavelengths of light produced by stars and galaxies. The greater the distance, the more the light is stretched.Astronomers measure that effect by looking for the “barcodes” that different chemical elements imprint in the object’s light. Each barcode keeps the same pattern. But it appears at a different place in the object’s spectrum — the “rainbow” of colors produced when you break the light into its individual wavelengths. When an object is moving away from us, the patterns are shifted to longer wavelengths — toward the red end of the spectrum — the redshift.For galaxies that are especially far away, the wavelengths can be shifted into the infrared. But Earth’s atmosphere absorbs most infrared light. So the best way to study it is from space.But most telescopes in space aren’t big enough to see deeply into the universe, so they can’t see the earliest galaxies — or if they do see them, the galaxies look like fuzzy red blobs. Only one space telescope allows us to see those early galaxies as galaxies — Webb Space Telescope. More about that tomorrow. Script by Damond Benningfield

During its four years of life, the InSight lander recorded more than 1300 “marsquakes.” Most of them were tiny, and most were caused by space rocks slamming into Mars. But the largest quake it ever felt came from the planet’s insides, far below the surface. That’s an indication that Mars isn’t dead yet.The quake took place in May of 2022, just a few months before InSight’s mission ended. It was magnitude 4.7. By Earth standards, that’s not much – maybe strong enough to feel, but not strong enough to cause any damage. But by Mars standards, it was a whopper – five times more powerful than the second-strongest quake. And it rattled around the planet for six hours.The quake was centered about 1400 miles away from InSight, in a region with a rugged surface. At first, scientists suspected the quake was caused by a large meteorite impact. That would’ve created a crater a thousand feet across, and blown away dust on the surface for miles around.So they scoured pictures taken by eight spacecraft in orbit around Mars. But they didn’t find a thing – no crater, no blast zone. That means the quake probably originated inside the planet, at a depth of about 11 to 17 miles. It might have been triggered by movement along a fault line. So even though the Martian crust isn’t made of moving plates, as Earth’s is, there may still be a good bit of shakin’ and rattlin’ below the surface of Mars. Script by Damond Benningfield

Olympus Mons is the Mauna Loa of Mars. Like the mountain on the island of Hawaii, it’s the largest volcano on its planet —in this case, Mars. Also like Mauna Loa, it built up as molten rock bubbled through a “hotspot” in the crust. Finally, Olympus Mons might once have stood in the middle of an ocean.Olympus Mons is almost 13 miles high, and covers an area the size of France – much bigger than Mauna Loa. That’s because it never moved away from the hotspot, so it kept on building for billions of years. Today, it’s either dormant or extinct.It stands on a wide base that’s about four miles high, with sheer cliffs all around. A recent study says the top of the base shows evidence of contact with water.Scientists have already seen the possible shoreline of a shallow ocean. The ocean vanished long ago, as Mars grew colder and lost most of its air.The study found features along the rim of the Olympus Mons base that look like they formed when lava spilled into liquid water – supporting the idea of a long-gone ocean. So Olympus Mons might once have been not only the biggest volcano on Mars, but the biggest island as well.Mars is inching into the dawn sky. It’s quite close to the Sun, though, and it rises at a shallow angle. If you’re in Hawaii or southern Florida or Texas, you might spot it quite low in the southeast before sunrise. The rest of the U.S. won’t see it for a few weeks.More about Mars tomorrow. Script by Damond Benningfield