FirstLight Astronomy Club

33°29.6'N / 117°06.8'W / 1190 ft.

Quix Time Redux

Quiz time again! This time we’ll be looking at some of our neighbor planets and their funky moves on the dance floor that we call our solar system. All the following are true or false. Put on your thinking cap!

Statement 1: There are places on Mercury that actually see double sunsets.

Mercury, the first planet from the sun is very close to our star, and as a result has felt a stronger gravitational pull than the rest of us. This greater pull actually brakes the planet into a slower spin time, a slower “rotation.”

Consequently one Mercurian “day,” one complete planetary pirouette, is nearly 59 earth days in length. And you thought your days were long.

Its year, how long it takes to go around the sun once, is only 88 earth days. This and the fact that its orbit isn’t a nice perfect circle make for some crazy phenomena.

The sun is actually in Mercury’s sky for 2-4 months at a time. You can imagine that a very close sun beating down for months nonstop can make for some pretty oppressively hot temperatures. Try 800 ˚F worth of hot.

Conversely, the long months of no sun at all result in temperatures that plunge to about -280 ˚C. Over one thousand degrees difference between nighttime and daytime probably disqualifies Mercury as a popular tourist spot.

Moreover, Mercury’s orbital geometry makes for a particularly strange occurrence. Because of the combination of slow rotation, quick revolution, and oblong orbit, there are places on Mercury where the sun will slowly sink below horizon, then surprisingly rise again, only to sink below a second time. Granted this takes several weeks to accomplish, but you can imagine this is one singular event in this solar system of ours. (Answer: True)

Statement 2: A day on Venus is longer than its year.

Venus, closer to the sun than we are, takes a shorter time to buzz around it; two hundred twenty-five days compared to our 365. But it takes even longer to spin around even once on its axis. A single “day” on Venus, one complete spin, lasts 243 Earth days! Combined with its revolution, the sun is “up” in that sky for about 2 months.

And of course it is “down” – below horizon - for another couple months, as well. But does that mean it is really hot during the venusian daytime and really cold during night? Not by any stretch of the imagination.

First, no one ever sees the sun in the sky on Venus, it is so unbelievably cloudy there. But that same cloud cover acts like a monster blanket, keeping it scorching hot all the time, day and night. The average temperature is nearly 900 degrees Fahrenheit, hundreds of degrees hotter than your stove at full blast. (Answer: True)

Statement 3: Mars has two moons, but soon it will have only one!

There are two tiny little satellites orbiting our outer neighbor Mars. Tiny is perhaps too weak a word. They are but miles across. Phobos is just 17 miles through. Deimos, farther out than Phobos, is only a 9-mile chunk of rock, the size of a decent sized city.

The small mass of these two means their gravity is near zero. A high jumper who can clear 6 feet on earth could set the bar to over a mile and a half on Phobos - and clear it easily.

An observer on Mars looking for his moons can see just a bright speck as Deimos passes over. But as Deimos passes over one way, Phobos races by overhead in the opposite direction, twice a day.

Poor Phobos, like the name implies, has reason to fear. It passes over twice a day because it orbits so dangerously close to Mars. In fact, it is on a collision course with its parent.

So close means Mars, via the laws of gravitational physics, will eventually pull Phobos into itself. In the next 50 million years or so, Phobos is doomed to crash into the planet or break up into bits giving Mars a tiny, temporary ring system. This will leave Deimos as the lone Martian satellite. (Answer: True)

Hope you did well. Until next time, clear skies!

Goodbye Night Sky - Light Pollution and its Devastating Effects

There’s a great feeling that comes over us lovers of the brilliant night skies when we see the next generation get all lit up about it, too. We derive hope when a young person asks us questions about why Saturn has rings or what a star is made of or why the Moon makes those shapes. In there somewhere might be a future astronomer.

But what can also get us going is when we see the torch passed to the next generation of those who want to save our skies from an archnemesis many of us are unaware of – light pollution. Such a crusader is what I found recently in a young girl named Anzy McWha.

But what can also get us going is when we see the torch passed to the next generation of those who want to save our skies from an archnemesis many of us are unaware of – light pollution. Such a crusader is what I found recently in a young girl named Anzy McWha.

Anzy lives with her parents and little sister in Fallbrook, a city not known as a sprawling megametropolis. But even here the subtle saboteur of the skies can rear its ugly head.

Attempting to watch the Perseid meteor shower last year, nine-year-old Anzy found that it was considerably more difficult than she had anticipated.

Watching a meteor shower is pretty much like attending a play, it’s a no-effort event. You go out, let your eyes adjust, then look up and watch it happen. But Anzy and her mom found that it wasn’t so easy to do when a neighbor’s light lit up her backyard like the rising sun.

They had to hide in the shadow of their motorhome to attempt to see anything at all.

A couple months later her school, Sage Meadows Elementary in Fallbrook, went for a camping trip to the Mojave Desert. It was there that she discovered what experienced sky watchers know already.

“I was completely awed at how many stars I could see,” she says. It was there that this third-grader realized that we humans were ruining the skies with our artificial lighting.

What Anzy did next is what separates her from many of the rest of us. Instead of whining about it and then carrying on as if nothing happened, she decided to do something. She researched light pollution, did a project on it, and shared her findings with me a couple weeks ago at her home in Fallbrook. This is what I learned…

What it is...

There are several victims of light pollution. The first is obvious to science types and poets everywhere: It just plain wrecks the beauty of the night sky for all of us. And it does this in many deceptive ways.

One, called “light trespass,” occurs when light from one person’s property literally trespasses onto someone else’s. We’ve all encountered it; many of us are guilty of it. We all know of the neighbors or businesses nearby who feel it their civic duty to illuminate the known universe.

“Light glare” happens when lights get into your eyes rather than merely lighting the path in front of you. It’s not unlike being on stage where it is very difficult to see the audience because of the glare of the lights. But offstage, outside at night, it serves no purpose and can be dangerous.

“Light clutter” is just that - the parking lot or casino or auto mall that feels it vital for the good of society to completely overkill the lighting, using twenty lights when five will do.

“Urban light glow” is the one astronomers are most enraged by. The name says it all. It results in part from the previous three acting together. When light is unnecessarily aimed or reflected up into the sky, it casts an eerie sky glow wiping stars right off the horizon and eliminating all but the brightest stars above.

And all this costs the United States over a billion dollars (that’s “billion” with a “b”) in completely wasted light every year.

In a nighttime visit with Scott Kardel, the public relations director at Palomar Observatory, Anzy and her family and I got to see firsthand what The Glow is doing to research at one of the world’s premiere telescopes. Even with our not-too-sensitive human eyes, we could see what seemed like glowing ghostly domes over Temecula, Palm Springs, Oceanside, Escondido, and San Diego.

“People have either forgotten about what goes on up here or are under the false impression that we have special filters which make it all better, which we don’t!” reports Kardel.

“It not only ruins the images of long exposures of the sky, but important spectral work gets compromised, too,” he tells me. The spectra of objects in the sky – an array of all their visible wavelengths - reveal the compositions of stars and galaxies, essentially what the visible universe is made of. “The spectra of local artificial lights get mixed in with the spectra of what we are investigating, which makes it very difficult to decipher what’s going on up there.”

One astronomer recently told Kardel that he gets better results from smaller scopes in darker locations. Ouch.

The Other Victims

Those of us who are way too focused on the night sky forget that there is another population that is adversely affected by our unnatural desire to turn night into day. Anzy reminded me of these forgotten victims.

Animals of all kinds since time immemorial have used the skies to navigate, to migrate, to find mates, to time their breeding seasons. Our introduction of the nightly glow has not left them unaffected.

“Some insects, migrating toads, and salamanders are attracted to artificial light, and then aimlessly walk or fly around the light source. This makes it easier for predators to prey on them,” says Anzy.

There are hundreds of species of birds that migrate each year, many of which use the night sky to help them. Flying low, and confused by artificial lighting, many thousands die flying into buildings. Many more die from exhaustion from all the extra effort of misnavigating through a sea of man-made lighting.

Sea turtles when hatched use visual light cues to make their way to the ocean. But if there is careless human development going on near their birthplace, turtles can make their way towards those unnatural lights instead. On that path of death they are easy targets for predators - and automobiles.

The biological clocks of many animals in part rely on the day/night cycles and other natural lighting cues. When an area is flooded with artificial lights, the natural rhythms of the animals are offset and their sleep cycles and breeding rituals get confused. This results in them becoming easier targets for prey, or they might breed before the local food supply is ready for them.

Humans, too, have natural rhythms based on normal day and night cycles. We all know that a passive form of torture is to keep lights on during sleep time. But did you know that artificial lighting and its adverse affects on us have been linked to such diverse medical problems as myopia and breast cancer?

Common Sense Answers

So what can we do?

“Use common sense,” Anzy tells me matter-of-factly, but respectfully. Can’t argue with that. Not using a particular light? Turn it off. Too many lights? Remove some. Light pointing to the sky? There’s no reason for that; take it out.

But what about safety? Shouldn’t we light up an area to feel safe?

“But that doesn’t mean putting in the brightest light we can find, blinding everyone in the area, creating light trespass, and lighting up the night sky,” answers the young advocate.

There are all kinds of “good” lights we can get from the hardware store; lights that minimally affect nature, the sky, and our neighbors – and keep us safe. These sky-friendly lights will soon be marked “IDA-approved.”

The IDA is the International Dark-Sky Association, an organization founded to reclaim the skies. They have an entire list of good lights, all of which essentially aim the light downwards, away from the sky and neighbors and eyes. (Find out more about them and all kinds of light pollution info at darksky.org.)

But their approved lights cost a little more than regular lighting. To no one’s surprise, young Anzy has a responsible answer for that, as well.

Not only do these good lights greatly reduce light pollution – a good reason for getting them in and of itself - but the lower wattage of the IDA lights means using less electricity. “They pay for themselves in two years!” says Anzy.

Her mom, Jane, adds to that. “We can’t go anywhere now without Anzy giving a running commentary on the lights we pass by…”
“Yeah, we say ‘bad light, good light, bad light, bad light, bad light, good light,’” Anzy says, finishing her mom’s sentence.

The Flick of a Switch

Anzy’s advice for dealing with a neighbor with a lighting problem? “Be really nice, tell them about the problems of bad lighting, and help them to find remedies for their situation.” That’s being a good neighbor.

Back at Palomar Kardel, involved in the local politics of lighting, goes further. He says that Riverside and San Diego Counties have laws that govern what type of lights may be used and when they can be lit. He says that if there is an issue with someone’s light, if they don’t listen to your friendly advice, to call the City or County Planning office and report it.

Being responsible for light pollution helps the environment, saves money, keeps us healthier, and brings back the night skies for us and future generations.

“Landfill problems and water pollution will take some time,” concludes Anzy McWha, wise beyond her years, “but light pollution can be solved by the flick of a switch.”
Temecula Valley High School / Temecula, CA · Some images © Gemini Observatory/AURA Contact Me