Skywatch Line for Monday and Tuesday June 24th and 25th, written by Joe Slomka
This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday June 24th and 25th, written by Joe Slomka.
The Sun sets at 8:38 PM; night falls at 10:55. Dawn begins at 3:02 AM and ends with Sunrise at 5:19.
The constellation Capricornus displays the Moon on both nights. Monday’s 18-day-old Moon sets at 7:41 AM; by 4 AM it is 26° high in the South, 32 arc-minutes and sets at 8:59 AM, Tuesday. By 4 AM, Wednesday, it is 31° high in the South, 32 arc-minutes 78% illuminated and sets at 10:17 AM.
Planets make a brief appearance in the evening sky. Gemini hosts Venus and Mercury in the Northwest. By 8 PM, Venus lies close to the horizon, blazing with minus 3rd magnitude, 9 arc-seconds in size, 9° high and sets at 8:58 PM. Mercury, 6° below Venus, simmers with minus 1st magnitude, 5 arc-seconds, 4° high, 88% lit and sets at 9:29 PM.
The rest of the planets reside in the brightening sky. Saturn, in Aquarius, is still the first to appear 32° above the Moon, rises at 12:30 AM, shines with 1st magnitude, 17 arc-seconds and 33° high in the Southeast. Neptune is next in Pisces, 10° above Saturn, 8th magnitude, 2 arc-seconds and rises at 12:49 AM. Fourth: two° from Neptune, Mars rises in eastern Aries at 2:25 AM, 1st magnitude and 5 arc-seconds. Taurus displays Uranus and Jupiter. Uranus, 13° above Mars, rises at 3:02 AM, 5th magnitude and 3 arc-seconds. Jupiter, 11 above Uranus and 27° from the Sun, rises at 3:41 AM, minus 2nd magnitude, and 3° in the Northeast. All these planets set during daytime and are either fully illuminated or close to it.
About 7:15 AM, on June 30, 1908, a bright object roared out of the sky and exploded over a Siberian forest. The resulting blast knocked people off their feet 70 kilometers away. Night skies were so bright that one could read a newspaper at midnight. Barometers around the world monitored the blast wave. Sunday is the 113th anniversary of the Tunguska Event.
The region, near the Tunguska River, was so remote that it took years for word to arrive at Moscow. Twenty years later, scientist Leonid Kulik led an expedition. He found the forest devastated for miles, with trees felled in a radial pattern from a central area. Suspecting a meteor, the expedition dredged the swamp to no avail.
Thanks to microscopic traces, we now know that the object was an asteroid that entered the Earth’s atmosphere. It exploded several miles above the surface with a force between three and five times the Hiroshima Atomic Bomb. Research also revealed that the object was smaller than first thought.
In 1947, a large asteroid broke apart and impacted the Kamchatka Peninsula, also in Russia. Pictures exist showing Soviet trucks pulling thousand kilo meteorites from the ground. Today, meteor collectors buy pieces of the Sikote-Alin meteorite, as it is now called.
On February 15th 2013, a 7000-ton asteroid exploded above the Russian town of Chelyabinsk. Like Tunguska, it devastated the town with the force of 30 Hiroshima bombs, damaging buildings and injuring people.
Clear Skies Joe Slomka