“I see Earth! It is so beautiful.”
The era of human space travel began on April 12, 1961, when the Soviet Union launched cosmonaut Yuri Gagarin into orbit. Gagarin's Vostok rocket lifted off at 5:30 am Moscow time (when corrected for US time zones, that would've been on the evening of April 11, but for the purpose of international observances, Gagarin's historic flight is celebrated on the 12th). Since the launch of Vostok 1, more than 500 men and women from various nations have flown in space.
Why Didn't We Observe Easter in March?
Easter is usually the Sunday following the first full Moon of Spring, but this year the equinox and the full Moon both occurred on March 20, so under the usual rule, Easter ordinarily would've been on Sunday, March 24...but it wasn't. That's because for the purposes of determining Easter, an obscure ecclesiastical rule considers the spring equinox to always be March 21 (even if it really isn't). Most years, that doesn't make much difference, but this year it does, so despite the fact that March 20 was both the actual equinox and first full Moon of spring, Easter is observed on the Sunday following this full Moon of April 19, or on April 21. Since Easter is supposed to occur between March 22-April 25, this is a rather late Easter.
The Meteors That "Fell Like Rain"
The Lyrid meteor shower, one of the oldest-known meteor showers, peaks on the morning of April 23, with Chinese records of this display dating back to 687 BC, when meteors were described as "falling like rain." The subjective language makes it rather difficult to compare this shower to others for which actual rates are known, such as the Perseids or the Leonids, which have both been described with equally colorful similes. This display usually produces about 10-15 meteors per hour on the peak date, apparently radiating from the constellation Lyra the Harp, after which it's named. However, the shower is active for a longer period, from April 16-25, when Earth passes through the dusty path of Comet Thatcher, which was discovered in 1861. Typically, the Lyrids are best observed shortly before dawn on the morning of the 23rd. This year, however, the light of a waning gibbous Moon may interfere, washing fainter meteors from view and reducing the numbers to 3-5 per hour.
Another meteor shower—and one of two that are associated with Halley's Comet—peaks on May 5. This is the Eta Aquarid display, which is active May 1-12, with a broad plateau rather than a sharp peak, offering elevated rates of meteors several days before and after the peak date. This year, the peak coincides with a day-old waxing crescent Moon that sets early in the evening, leaving the night sky moonless and dark. However, because the shower's radiant in the constellation Aquarius the Water-Carrier doesn't rise until about 3:00 am, the viewing window isn't open for very long before the predawn twilight starts to become visible around 5:00 am, with sunrise at 6:11 am. The other shower associated with Halley's Comet is the Orionid display, which peaks in October.
Shepard's Suborbital Shot
On May 5, 1961, astronaut Alan Shepard became the first American space traveler, and even though his trip was suborbital, he did reach an altitude of 186 kilometers (116 miles), satisfying an internationally recognized definition of "outer space" being 100 kilometers, or 62 miles. 15 minutes after launch his Mercury space capsule, nicknamed "Freedom 7," splashed down in the Atlantic Ocean 486 kilometers (302-miles) from its Florida launch site, and was retrieved by a US naval vessel.
We'll Put Stars in Your Eyes
May 11 is Astronomy Day, founded in 1973 by the Astronomical Association of Northern California. Now a worldwide observance, it's a day for astronomers to share their love of stargazing with the public, and is always held on a Saturday in April or May nearest the first quarter Moon. Check with your local astronomy club, science museum, planetarium, or observatory to find out how they're celebrating. At the Academy, Bay Area astronomy-related organizations will have display tables and demonstrations to help visitors discover the many opportunities at various levels to explore the wonders of the night sky! In the evening, some will have telescopes available (weather-permitting) for the public to observe the Moon and other celestial objects.
The Day the Sun Stands Still
On June 21, Earth's North Pole leans toward the Sun as much as possible (23.5 degrees). This is recognized as the June solstice in the northern hemisphere, and more specifically on that half of the planet, as the summer solstice, marking the start of the season. The word "solstice" means "Sun stopped," and observers following sunrises and sunsets since the beginning of the year notice that these points on the horizon have been gradually moving northward. On the solstice, that northward movement stops, then starts returning southward after that. In a sense, then, the Sun "stands still" on the horizon on the solstice, following its longest, highest arc across the sky on that day.
The Big Bang of 1908
On the morning of June 30, 1908, the largest impact on Earth in recorded history took place when a small asteroid or comet entered Earth's atmosphere and exploded over a region in eastern Siberia, called Tunguska. The object is thought to have measured 60-180 meters (200-600 feet) across and never reached the ground, exploding in the atmosphere. In some estimates, the explosion released up to 1000 times the energy of the atomic bomb dropped on Hiroshima in World War II, and when the shockwave reached the ground, it flattened 2000 square kilometers (770 square miles) of heavy forest, knocking down an estimated 80 million trees. Today, that event is commemorated around the world as Asteroid Day, calling attention to the potential hazards posed by asteroid impacts.
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