Meteors raining down this month
GATEHOUSE NEWS SERVICE
erseid meteor time is upon us. Occurring every August, the chance to witness one of the strongest meteor showers of the year while weather is warm is a highlight on the calendar of many night sky watchers.
Were you brought up to call them “shooting stars”? We don’t hear that term very often anymore. Indeed, they look like perhaps a star detached from the big night sky over our heads, as if we were inside an inverted bowl with stars glued in place.
It’s also not unlike one of those planetarium displays you can buy for your house. One time I decorated the ceiling of the study in our house with small plastic planets, which were supposed to hang from the ceiling by a piece of fishing line secured by a bit of putty. Of course, the planets glowed when the lights were turned off. It made a nice symbolic representation of the solar system, until we had not a meteor shower but a planet shower inside the house. Gradually, one by one, most of the planets obeyed the law of gravity and were found on the floor!
Back to the meteors. As you may know, they are actually bits of rock, from the size of grains of sands to the rare boulder sizes, which circle the sun and are swept up by the Earth’s gravity. They come from either disintegrated asteroids or the melt-down of comets. The swarm of meteors follows the old path of the asteroid or comet.
Many of those paths intersect with Earth’s orbit. If the meteors are spread out all along their orbit, each year at an appointed time, the Earth becomes peppered.
As they crash through our upper atmosphere, the pieces of cosmic rock vaporize, and the super-heated air around them glows, allowing you to see the spectacle.
About 50 meteors could be seen an hour under ideal conditions at the peak of the Perseid Meteor Shower. Unfortunately this year we have the last-quarter moon rising around midnight on Aug. 13. The moon phase will be larger during the nights before the 13th and will rise earlier than midnight. The sky will be bright with moonlight, hiding most of the meteors.
The shower peaks on the night of Aug. 11-12, but the meteors continue to cascade for about a week before and after.
Fortunately many of them are bright, so you may still see a few if you look long enough. A casual look for five minutes may be disappointing, but you never know what to expect. You could be very lucky and see a couple bright ones at once or within seconds of each other.
Meteor showers are named for the constellation in which they appear to radiate. The Perseids appear to emanate from the constellation Perseus, which rises in the northeast around 11:30 p.m. the higher the radiant is in the sky, the more meteors you may see; that means you have a better chance between midnight and morning twilight when many of us are sawing wood.
They are always a delight. Meteors can appear at any hour of the night, any time of year, startling anyone looking up at the right time. Bright ones normally have a gray trail behind them, which vanishes quickly.
While you’re out, enjoy the beautiful planet Jupiter. The fifth planet shines in the southeastern sky during the evening this month. A small telescope will readily show the four brightest moons of Jupiter, as well as the disc of the giant planet. Although huge, it is so distant it will still appear small in your telescope. Larger backyard telescopes, if the Earth’s blanket of air is steady, can reveal dark and light bands and spots in the planet’s perpetually cloudy atmosphere.
In late July, an amateur astronomer hobbyist discovered a new spot on Jupiter that thrilled professional astronomers around the globe; it appears to be a scar from a collision with a comet or asteroid. The finding came close to 15 years after the famed celestial “crime scene” where a comet, broken into pieces, was actually observed striking Jupiter and leaving behind dark spots like bullet holes. Fortunately, Jupiter’s clouds healed up well.
Once again, be thankful it wasn’t the Earth!
Bright Venus may be seen low in the east before dawn—another place even cloudier than Earth.
Keep looking up!