We’re now back to standard time, so hopefully you’ve moved your clocks back to gain an extra hour of sleep. Most folks don’t need to worry about changing their clocks because the clocks automatically take care of the change.
The only ones I know of who have to worry about daylight saving time vs. standard time are students in astronomy classes who are tracking the motion of the sun and see that the sun gets up highest around noon during standard time and while it is up highest around 1 p.m. during daylight saving time. Those of us who drive to work also notice the change because the sun is up higher in the sky in the morning and lower in the sky as we drive home.
Tuesday night will bring us a nice long total lunar eclipse as the full moon slips into the darkest part of Earth’s shadow (the umbra) at 1:09 a.m. By 2:17 a.m. it will be totally inside Earth’s umbra and will take on the orange-red color for which total lunar eclipses are famous.
The total lunar eclipse phase will last until 3:42 a.m. and the moon will be out of the umbra by 4:49 a.m. (all standard time). You can see all of this happening high up in the southwestern sky. The full moon will be between the constellations of Aries and Taurus just above the head of Cetus.
During totality, the full moon changes to the orange-red color because the orange and red colors of sunlight traveling through Earth’s atmosphere are able to bend around the Earth and reach the moon even though it is in total shadow. The shorter wavelength colors such as the greens, blues and purples get scattered away. At the center of the umbra, the blue and purple colors are dimmed by almost a billion times while the orange and red colors are dimmed just 25,000 times.
The totally eclipsed moon will take on an orange, red or even a brown color depending on how much dust there is in our atmosphere globally. A lot of dust from a volcanic eruption that has had time to spread around the globe can make the totally eclipsed moon appear a dark brown, almost black, while a global dust-free atmosphere will make the moon have a light orange color.
Those who have telescopes can take part in the crater timing research project. Observers simply note when the umbra crosses a crater’s center (going into the umbra and then leaving the umbra). The crater timings will help us measure the size of Earth’s umbra. Earth’s umbra is slightly larger (on average about 54 miles larger) because of Earth’s atmosphere.
We’re still trying to understand why the size of the umbra changes from one eclipse to the next — the increase in size varies from as little as 47 miles to as much as 65 miles.
On Wednesday morning, a nearly full moon will be next to the Pleiades star cluster at the shoulder of Taurus. Two mornings later, on Friday, a waning gibbous moon will be next to Mars.
New crater on Mars
One recent piece of Mars news is that the InSight lander was able to detect a large marsquake when a meteoroid hit its surface on Dec. 24 about 2,150 miles from InSight. Two months later, the Mars Reconnaissance Orbiter team poring over images of Mars’ surface taken by the satellite found the crater formed by the impact.
The meteoroid that made the crater was somewhere between 16 to 39 feet across and it blasted out a crater 492 feet across and 70 feet deep. A meteoroid that size would have burned up in Earth’s atmosphere but Mars’ thin atmosphere barely slowed it down.
This is one of the largest craters we’ve detected forming while we were looking (or listening). The impact also uncovered subsurface water ice. In fact, this subsurface ice is the closest we’ve seen to Mars’ equator at 35 degrees north latitude (about the same latitude as Bakersfield, and we’re also really interested in water as well).
In the night sky
In our evening sky, the king planet, Jupiter, dominates the eastern sky as it shines brighter than any star in the night sky. Jupiter will already be up at sunset. Jupiter continues its slow travel among the dim stars of Pisces. Saturn will be high up in the southwest near the tail of Capricornus.
The night of Nov. 17/18 is the peak of the Leonid meteor shower. The moon will be a waning crescent by then and it will rise about two hours after the radiant (the point from which the meteors appear to shoot), so we should have a good view.
The Leonids happen as Earth passes through the dust trail left behind by Comet 55P/Tempel-Tuttle to produce 10 to 15 meteors per hour. However, we may see bursts up to 250 meteors on the following evening as we plow through a stream ejected by the comet in 1733 and a smaller burst a day later from a stream ejected in 1800.
Tickets are on sale for “Black Holes,” showing on Nov. 17 at the William M. Thomas Planetarium. Visit vallitix.com/planetarium to purchase.