On Saturday, March 28, 2020 at 8:30 p.m, all around the world, it’s “Earth Hour,”, when a lot of public and private lighting will be switched-off for 60 minutes. Earth Hour is a grassroots movements for the environment and, this year, perhaps also a moment of solidarity for the planet, and all of us upon it.
However, you can also use Saturday’s hour of darkness to get connected not only to our planet, but to another planet, our moon, and bright stars aplenty. All while the lights are off, which ought to reduce light pollution and increase the clarity of the night sky.
Here’s what to find in the night sky during Earth Hour—and it includes something extra-special.
How to see Venus, the moon and the Pleiades
Visible before, during and after “Earth Hour” will be an exceptional sight of a planet, a crescent moon and a sparkling star cluster all close together. Due west, above where the sun set, you’ll find brilliant Venus and, to its left, an 18% illuminated crescent moon. Look just above and you’ll see the Pleiades, a collection of seven close bright stars that together make-up one of the nearest star clusters to us. The Pleiades are also known as the “Seven Sisters.” If you’ve got any kind of binoculars, go fetch them—the Pleiades looks fantastic through binoculars (though less so a telescope).
These three incredible sights won’t be together on Friday nor Sunday nights, so make sure you look on Saturday night during, or close to, “Earth Hour.”
What other stars are out on Saturday night?
Let’s go anti-clockwise from Saturday’s “holy trinity” of celestial highlights. Look towards the southwest around 8:30 p.m. and you’ll see the unmistakable stars of Orion’s Belt—Alnitak, Alnilam and Mintaka—and, directly above, red supergiant Betelgeuse. Is it going to explode and go supernova? probably not, but in any case, it’s about to depart the night sky for six months. So let’s hope it holds on …
How to see the brightest star in the night sky
Follow Orion’s Belt left, towards the south, and you’ll see Sirius, the “Dog Star” in the constellation of Canis Major. The brightest star in the night sky, Sirius is a mere 8.7 light years from us, so the closest star we can see at night from the northern hemisphere.
Now face east
It’s spring, so there are plenty of famously seasonal stars rising in the east. Look above your head and you’ll the Big Dipper, its “handle” pointing downwards. Follow that handle in an arc and you’ll come to a reddish star, Arcturus, low on the eastern horizon. Arcturus is 36 light years distant in the constellation Boötes and a red giant star.
How to find Leo the Lion
Between the Big Dipper and Orion—roughly south but high in the sky—is the constellation of Leo. Dominated by the star Denebola at the tip of its tail and, closer to Orion, Regulus at one of the lion’s front paws, Leo is most famous for the “question mark” shape that makes-up the lion’s head. It’s actually backwards, with Regulus as the period.
Leo and the ‘realm of galaxies’
However, what Leo is really interesting for is that it’s in a part of the night sky where the most galaxies can be viewed (though not with the naked eye). Between Denebola and Regulus there’s the M96 or Leo I Group of galaxies, a cluster of about nine galaxies around 30 million light-years from Earth. Despite that immense, unimaginable distance, all are just a small part of what’s known as the “local group” of galaxies close to our home, the Milky Way.
Wishing you clear skies and wide eyes.