Eclipses Belong to Families That Span Millennia

iStock
iStock

If you’re lucky enough to see the solar eclipse when it passes over America on August 21, you’ll bear witness to a centuries-long legacy. That’s because total eclipses of the sun aren’t isolated incidents that occur at random. They belong to interconnected eclipse families that humans have been using to track the phenomena since long before the first telescope was invented.

In the latest installment of StarTalk on Mashable, Neil deGrasse Tyson chats with meteorologist Joe Rao about the science behind eclipse families. According to Rao, eclipses follow Saros cycles which repeat every 18 years, 11 days, 8 hours. Astronomers keep track of many different Saros cycles. The eclipse on August 21, for example, is a member of the family Solar Saros 145. Every 18 years a Saros 145 eclipse falls over a different third of the Earth. In 1999, the great American eclipse’s “cousin” appeared in the skies over Europe and south Asia, and 18 years before that another relative could be seen over modern Russia. The Solar Saros clan can be traced all the way back to 1639 and it will keep going until 3009.

Today, scientists have space-age technology that allows them to track the moment of totality down to a fraction of a second. But thousands of years ago, before such satellite-tracking equipment was invented, ancient Babylonians only knew what they could observe from Earth. Their eclipse calculations ended up serving them pretty well: They were able to predict the same 18-year cycle we know to be true today.

Saros 145 isn’t the only family of eclipses making its way around the Earth. There are enough solar eclipse cycles to make the event a fairly common occurrence. If you’re curious to see how many will happen in your lifetime, here’s where you can calculate the number.

[h/t Mashable]

A Super Pink Moon—the Biggest Supermoon of 2020—Is Coming In April

April's super pink moon will be extra big and bright (but still white).
April's super pink moon will be extra big and bright (but still white).
jakkapan21/iStock via Getty Images

The sky has already given us several spectacular reasons to look up this year. In addition to a few beautiful full moons, we’ve also gotten opportunities to see the moon share a “kiss” with Venus and even make Mars briefly disappear.

In early April, avid sky-gazers are in for another treat—a super pink moon, the biggest supermoon of 2020. This full moon is considered a supermoon because it coincides with the moon’s perigee, or the point in the moon’s monthly orbit when it’s closest to Earth. According to EarthSky, the lunar perigee occurs on April 7 at 2:08 p.m. EST, and the peak of the full moon follows just hours later, at 10:35 p.m. EST.

How a supermoon is different.

Since the super pink moon will be closer to Earth than any other full moon this year, it will be 2020’s biggest and brightest. It’s also the second of three consecutive supermoons, sandwiched between March’s worm moon and May’s flower moon. Because supermoons only appear about 7 percent bigger and 15 percent brighter than regular full moons, you might not notice a huge difference—but even the most ordinary full moon is pretty breathtaking, so the super pink moon is worth an upward glance when night falls on April 7.

The meaning of pink moon.

Despite its name, the super pink moon will still shine with a normal golden-white glow. As The Old Farmer’s Almanac explains, April’s full moon derives its misleading moniker from an eastern North American wildflower called Phlox subulata, or moss pink, that usually blooms in early April. It’s also called the paschal moon, since its timing helps the Catholic Church set the date for Easter (the word paschal means “of or relating to Easter”).

[h/t EarthSky]

Are Any of the Scientific Instruments Left on the Moon By the Apollo Astronauts Still Functional?

Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Heritage Space/Heritage Images/Getty Images

C Stuart Hardwick:

The retroreflectors left as part of the Apollo Lunar Ranging Experiment are still fully functional, though their reflective efficiency has diminished over the years.

This deterioration is actually now delivering valuable data. The deterioration has multiple causes including micrometeorite impacts and dust deposition on the reflector surface, and chemical degradation of the mirror surface on the underside—among other things.

As technology has advanced, ground station sensitivity has been repeatedly upgraded faster than the reflectors have deteriorated. As a result, measurements have gotten better, not worse, and measurements of the degradation itself have, among other things, lent support to the idea that static electric charge gives the moon an ephemeral periodic near-surface pseudo-atmosphere of electrically levitating dust.

No other Apollo experiments on the moon remain functional. All the missions except the first included experiment packages powered by radiothermoelectric generators (RTGs), which operated until they were ordered to shut down on September 30, 1977. This was done to save money, but also because by then the RTGs could no longer power the transmitters or any instruments, and the control room used to maintain contact was needed for other purposes.

Because of fears that some problem might force Apollo 11 to abort back to orbit soon after landing, Apollo 11 deployed a simplified experiment package including a solar-powered seismometer which failed after 21 days.

This post originally appeared on Quora. Click here to view.

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