StarDate

It’s hard to imagine a less comfortable place for life than the clouds of Venus. They’re made mainly of sulfuric acid – something you wouldn’t want to dip your fingers into. Yet studies in the past few years are raising at least the possibility that microscopic life could inhabit those clouds.

There’s almost no way for anything to live on the surface of the planet. The atmosphere is too hot, dense, and toxic. But the clouds are about 30 miles high, where the conditions are more like those on Earth.

A few years ago, scientists reported finding phosphine in the clouds. On Earth, it’s a compound that’s almost always produced by living organisms. Other studies have found no trace of it. But earlier this year, astronomers reported finding new evidence of the compound.

Another study this year reported finding ammonia. On Earth, it’s produced mainly by living organisms and industrial processes. And yet another study said that some of the key building blocks in amino acids could survive in a high concentration of sulfuric acid.

None of that means that anything actually lives in the clouds. But it does mean that scientists will be taking a much closer look at Venus’s clouds in the years ahead.

Venus is the brilliant “evening star.” It’s quite low in the southwest as night falls. Tonight, it’s close to the upper right of the crescent Moon. It’ll be a little farther to the lower right of the Moon tomorrow night.

Script by Damond Benningfield

Star clusters line up in the evening sky at this time of year like pearls on a necklace. As the sky gets nice and dark, they climb straight up the northeastern sky. They stretch from the bright star Capella, which is quite low; up through the “W” of Cassiopeia; then to Cygnus, the tail of the swan, high overhead.

There’s a good line of clusters because that path outlines the Milky Way – the subtle glow of the disk of our home galaxy. Most of the clusters are classified as “open.” All of the stars in such a cluster were born together, from a giant cloud of gas and dust. But as the clusters orbit the center of the Milky Way, they’re slowly pulled apart. So over time, all the stars in such a cluster go their own way.

Perhaps the highlight of this path is the Double Cluster – two clusters in Perseus, just below Cassiopeia. Under dark skies, they’re visible to the unaided eye as a faint cloud of light.

Individually, the clusters are known as NGC 869 and 884. They’re about 7500 light-years away. Combined, their stars and gas add up to about 20 thousand times the mass of the Sun. And they’re quite young as stars go – about 14 million years. At that tender age, the clusters haven’t had time to fall apart. And with their great mass, they’re likely to hold together longer than most clusters – perhaps several hundred million years.

Tomorrow: the crescent Moon and the “evening star.”

Script by Damond Benningfield

Many people gripe when we “spring forward” in March, at the start of Daylight Saving Time. And many studies suggest they have reason to complain. For a few days after the switch, there’s an uptick in car accidents, workplace injuries, and even heart attacks. And a recent study shows other consequences: more junk food and less time at the gym.

Daylight Saving Time is observed across most of the United States and more than 70 other countries.

Originally, it was designed to save energy. By advancing the clock an hour during the longer days of summer, people would go to bed not long after dark, so they wouldn’t use as much electricity in the evenings. But it’s not clear if it really does save energy. Today, the big advantage is seen as recreational – people can spend more time outdoors.

But the loss of sleep seems to cause problems.

The new study, for example, looked at how people changed their health habits the day of the switch. Researchers found that people ate more junk food – the number of junk-food calories went up by about half. The effect was especially pronounced in the evenings and when the day of the change was cloudy. And the total time people spent at fitness centers went down by a third – especially among those who didn’t work out often, or lived farther from the gym.

The study found there was no impact from “falling back,” as we’ll do tonight – as Daylight Saving Time ends for another year.

Script by Damond Benningfield

To look at a modern calendar, you’d think the early Romans couldn’t count very well. Today, for example, is the first day of November, the eleventh month of the year. But the name “November” means the ninth month. The name is a holdover from the earliest Roman calendar, in which the year began with March.

The start of the year was moved to January a century before the time of Julius Caesar. He affirmed that order when he set up the basic calendar we use today. But the names of the months remained the same – even though some, like November, no longer made sense.

In the modern calendar, November 1st is just another day. But to the ancient Celts, it marked the beginning of a new season – and a new year. Summer ended on October 31st, when the cattle and sheep were brought in from the pastures. Winter and the new year started the next day.

That day was called Samhain. The Celts lit bonfires to help out the Sun, which was growing colder and more feeble as the long nights of winter approached.

Because it was like a crack in time – a dividing line between both seasons and years – Samhain was a time when the souls of the dead were thought to roam free. Families opened tombs to release friendly spirits, and brought them food and other gifts. And people wore masks to hide themselves from evil spirits. Many of those ancient customs have been incorporated into the modern-day celebration of Halloween.

Script by Damond Benningfield

Some “monstrous” stars decorate the Halloween sky this evening. They’re in Perseus, which is low in the northeast at nightfall but passes directly overhead in the wee hours of the morning. The constellation is marked by a couple of ribbons of moderately bright stars.

In mythology, Perseus rescued the princess Andromeda from a nasty sea monster. In one version of the story, he turned the monster to stone by showing him the head of Medusa, one of the Gorgons – monsters in their own right.

Four stars in the constellation are tied to that story. Together, they’re known as the Gorgons. And the most impressive of the four is quite the monster.

Gorgonea Tertia – the third Gorgon – is entering the final stage of its life. It converted the original hydrogen fuel in its core to helium, then converted the helium to carbon and oxygen. The core isn’t hot enough to continue the process, though, so it’s no longer generating energy. But it’s hot enough to push on the layers of gas around it, making the star puff up to enormous proportions.

Today, Gorgonea Tertia is roughly 150 times wider than the Sun. In the near future – on the astronomical timescale – the star will get even bigger and brighter. After that, it will eject its outer layers, creating a colorful bubble. But the bubble will quickly expand so much that it’ll fade from view. That will leave only the star’s hot but dead core – a meek end for a monstrous star.

Script by Damond Benningfield

Autumn’s evening skies offer some constellations with great names, intriguing back-stories, and beautiful star patterns. And then there’s Triangulum. As the name suggests, it consists of three main stars that form a triangle – an accurate if dull description of one of the smallest constellations.

The triangle looks like a thin wedge. And there’s an odd coincidence involving the stars at the base of the wedge: One of them is precisely third magnitude, while the other is precisely fourth magnitude. A lower number means a brighter star, so the third-magnitude star is the brighter of the two. Both stars are easily visible from dark skywatching sites, but more difficult targets from the city.

The brighter star is Beta Trianguli. It’s actually a binary – two stars bound together by gravity. The system is about 125 light-years from Earth. The other, Gamma Trianguli, is a little closer. The star at the tip of the wedge, Alpha Trianguli, is closer still. It’s in the process of swelling up to become a giant.

Perhaps the most impressive feature in Triangulum is M33, the Triangulum Galaxy. Through binoculars, it looks like a fuzzy star not far from Alpha. But that little smudge of light is a pinwheel of tens of billions of stars – three million light-years away.

Triangulum is in the east-northeast at nightfall. And this is a good time to look for it, because there’s no moonlight to overpower its faint stars.

Script by Damond Benningfield

The skies above most cities and towns are glowing. Artificial light sources beam a lot of their light into the sky. That makes it harder to see the heavens. And it can cause health problems, endanger wildlife, and waste both energy and money.

One big contributor to the problem is streetlights. They can be improved by adding shielding that directs their light downward, and by using the right kind of fixtures. One type of fixture that could help is L-E-Ds. They use less energy than most other types of lighting, they last longer, and their light can be concentrated on the ground, not the sky. As a result, many cities have replaced older streetlamps with L-E-Ds.

But experts on light pollution have some concerns about those fixtures. Because L-E-Ds are cheaper to operate and last longer than older lamps, some locations may increase the number of streetlights, for example.

Studies have found that, watt for watt, white L-E-Ds produce more sky glow than other types of lighting. And the color of the light can be a problem as well. L-E-Ds produce more intense blue light than some older streetlamps. That increases glare, and makes it harder for the eye to adapt when you go from a bright area to a darker one.

Experts do suggest, however, that warmer L-E-D fixtures, operating at lower levels, can light up the ground without making the skies glow even brighter.

Script by Damond Benningfield

There are many reasons you might feel tired, irritable, and headachy when you wake up in the morning – illness, allergies, noisy neighbors. But you might also blame it on too much light – especially blue light. Looking at your phone or TV before bedtime can mess with your natural sleep cycle.

Another source of trouble is outdoor lighting. Streetlamps, billboards, car headlights, and other sources fill the night with light. That creates a dome of light over most cities and towns – a dome of “sky glow.” In fact, 99 percent of all Americans live beneath such a dome.

The glow creates all kinds of problems. It prevents us from seeing the wonders of the universe. It can endanger wildlife. And many studies have shown that it can endanger our health as well.

That’s especially true with bluer light. Those wavelengths activate the receptors in the eye that we use most during the day. So they’re telling your body that it’s daytime, not night.

Exposure to bright outdoor lighting can suppress the body’s production of melatonin. That’s a hormone that plays an important role in the immune system, the health of several major organs, and the body’s natural rhythm. In particular, it can cause you to lose sleep, or to have a poor night’s sleep.

Experts recommend reducing the amount of outdoor light pollution, and making sure that streetlamps have a warmer glow – helping everyone to get a good night’s sleep.

More tomorrow.

Script by Damond Benningfield

When you walk from a brightly lit room into a dark one, you might stumble for a while until you can see what you’re doing. And the same thing happens when you step out under a dark night sky – it takes some time to see its full glory.

When you enter the darkness, your eyes adapt in several ways. First, the pupil opens wider, letting in more light. Second, the eye’s cones become more sensitive. They see color and detail, but they’re not very helpful when it’s dark.

Finally, the rods adapt. They see best under low light. But they need a special chemical to do that. The chemical goes away when it’s bright. It rebuilds when it turns dark, but it takes time – 20 to 30 minutes.

So if you’re watching the stars from your back yard, turn off the lights, and leave your phone alone. If you need some extra light, try a red flashlight – it won’t mess with your eyes.

One other thing that can enhance your view is averted vision. The rods are concentrated around the edge of the eye, so they do a better job when you look at a faint object out of the corner of your eye instead of straight on.

Two good targets for averted vision are in view by about 8:30 or 9. The Pleiades star cluster is low in the east-northeast, and looks like a tiny dipper. High above it is the Andromeda Galaxy, which looks like a tiny cloud. It’s the most-distant object that’s easily visible to the eye – but only when the eye is ready for the darkness.

Script by Damond Benningfield

Late-October evenings are great for skywatching. The nights are fairly long and cool. And there’s a lot to see. The Summer Triangle is still high in the west, and Taurus is climbing into view in the east. And this year, three planets are visible before midnight: Venus, Saturn, and Jupiter.

One thing that’s not visible for the next few evenings is the Moon. It doesn’t rise until the wee hours of the morning. So if you can get away from city lights, you should be treated to a beautiful view of the stars.

Dark skies are especially important for astronomers, allowing them to see deeper into the universe. But other things can limit the view. That includes clouds – not just on Earth, but in the stars.

Dust is sprinkled between the stars. And the farther you look, the more dust gets in the way. That obscuring effect is known as extinction. Astronomers have to account for it when they measure an object’s brightness, its color, and more. In some cases, they’re looking through a fairly uniform scattering of dust. But in others, they’re looking through dense clouds, which make it really tough to see what’s beyond.

Another concern is called seeing – the stability of the atmosphere. If the air is calm, the seeing is pretty good. But if it’s turbulent, it smears the view of the stars. Bad seeing makes the stars twinkle more fiercely. That’s a beautiful effect for casual skywatchers, but bad for astronomers.

Script by Damond Benningfield