Thursday, April 24, 2014
A super weekend of weather is underway across Maine. This is going to be an ideal weekend to enjoy all that Maine has to offer in summer. As a bonus we have an astronomical treat to accompany the meteorological forecast. Grab your favorite lawn chair, a blanket and something to drink because the year’s best meteor show is already underway. If you have seen a meteor or two the past couple of nights most likely you are seeing one of thousands of Perseid meteors that will streak across the sky this month.
While the peak of the meteor shower will take place in the wee hours Monday and Tuesday mornings, the shower itself started days ago and will continue much of the month. Why the next few nights are called the peak is those nights have the highest number of meteors per hour, but I all but guarantee you will see some meteors if you are up watching tonight.
In order to see the meteors you need to find a place with a view of the northeast sky. The good news is that the moon is setting in the western sky early enough this weekend that it won’t be a factor. You can see the approximate time of moonrise and set in your area above.
The reason we see these meteors every year in such a predictable manner is because the Earth crosses the orbital path of Comet Swift-Tuttle. The comet is the owner of the Perseid meteor shower. Debris from this comet litters the comet’s orbit, but we don’t really get into the meat of the comet rubble until after the first week of August. What you are seeing are small fragments from Comet Swift-Tuttle hurl into the Earth’s upper atmosphere at some 210,000 kilometers (130,000 miles) per hour, lighting up the nighttime with fast-moving Perseid meteors. Since the exact density of the rubble isn’t predictable some years are better than others with elevated numbers of meteors. There have been years where the number of meteors has exceeded 100 per hour!
The orbit of the Comet Swift-Tuttle is extremely oblong around the sun. The comet journey takes it from a point closet to the sun, and inside the orbit of Earth to as far away as outside the orbit of Pluto. This is when it’s farthest from the sun. The total time for this to take place is a whopping 133 years. As the comet, a dirty snowball of space rocks and debris gets close to the sun it warms and softens up the ices in the comet. As this happens fragments of fresh material get released into the tail of the comet and those pieces are what we will eventually see streaming across the summer night sky. Comet Swift-Tuttle last reached perihelion or the closest point to the sun back in December 1992 and will do so next in July 2126. You won’t be around to see it, but your great grandchildren will likely read about it on their Google glasses or imbedded brain chip or something.
Gardening this week If you have a sunny spot and a good size container, how about planting carrots? Carrots can be successfully grown in containers and you will be surprised how many you will get. One of the most important things is to not over water the soil. Check out the video below showing how I recently planted a container of carrots. I'll be updating the details of the weather on Twitter at @growingwisdom Please follow me there. Feel free to comment or ask questions too.Tweet
David Epstein has been a meteorologist for more than 25 years. He spent 16 years in Boston and currently freelances at WGME13 in Portland.
In 2006, David founded GrowingWisdom.com, a business producing educational and marketing videos for the green industry. He currently is a professor at Framingham State College, teaches Jan Plan at Colby College and owns Bloomscapes Inc., a landscape design business.
David authored "Gardens Of New England" and his work has been published in Grolier's Science Annual for 10 years. He lives in South Natick, Mass., and has a summer home in Harpswell.