Mars and Meteor Showers

I hope you've saved up your vacation time and sick days because there's a lot going on out there this month, in the middle of the night. And if you're in-between jobs, you might want to wait until the first of August to dress up those resumes. We have many sleepless nights ahead!

We'll begin with Mars, which is drifting ever nearer us in space, growing larger and brighter. By the end of the month, glowing at a brightly-polished -2.3, it clears the eastern horizon around 10:00 PM local time. In telescopes, its disk grows from 16" to 22" in diameter, the largest it has been since 1988.

The red planet's southern hemisphere is moving into spring. Again in telescopes, even small 'scopes if the sky is clear and still, we can watch the melting ice-cap shrink. Numerous other features - dark surface markings - might also be seen.

On the morning July 17th, Mars does a dance with the Moon, which is a rare treat indeed. This occultation of Mars will be visible across Central America, northern South America, Cuba ... just skimming the extreme southeastern U.S., where observers will witness Mars pass behind the edge of the Moon. The rest of the U.S. will see Mars, at magnitude -1.9, perched just off the edge of the moon. This occurs around 5:00 AM local time on the east coast, 2:00 AM out west.

Meanwhile, the other naked-eye planets are less conspicuous, loitering about the sun like moths at a back porch light. Venus and Saturn are less than 1⁰ apart on July 8th, but rise about 50 minutes before the sun. Jupiter and Mercury are about 1/3⁰ apart on the 25th, but are only 3⁰ above the western horizon, in the evening sky.

But we have meteor showers; lots and lots of meteor showers. This year, with a Full Moon falling on the 12th of August, the summer's best meteors will fall during the period around the preceding New Moon, which falls on July 29th. At that time, when dozens of Perseids are likely each night, the Piscis-Austrinid, South Delta Aquarid and Alpha Capricornid meteor showers are all peaking. The North Delta Aquarid and South Iota Aquarid meteor showers are also active. Mix in the usual odds and ends that streak, fall and tumble across the constellations on any given night and you have a night of star gazing Caligula would enjoy.

It's an interesting array of meteors during late July. The swift Perseids, streaking out of the northern sky, make the slower meteors from all those more southerly showers seem so much slower. The Perseids flash by at 59 km/sec, while the Alpha Capricornids move at a snail's pace of 23 km/sec. It's almost like interstellar gunplay, meteors shooting back forth from north to south and vice versa.

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