What's Up - March 2024

What's Up for March? Some close pair-ups with the Moon, and Mercury makes an appearance, a subtle lunar eclipse, and a chance to catch a comet.

In March, you'll find Jupiter shining brightly in the west during the early evening hours all month long. And on March 13th, it's joined by a crescent Moon so close that the pair will be visible together through binoculars. On the following evening, the Moon visits the Pleiades. This is another close pairing – with the five-day-old lunar crescent hanging right next to the bright star cluster – that will look great through a small telescope or binoculars.

Near the end of March, observers in the Northern Hemisphere will have the best opportunity of the year to catch a glimpse of Mercury in the evening sky. Look for it shining brightly low in the west following sunset.

Overnight on March 24th and into the 25th, the Moon will pass through the outer part of Earth's shadow, creating a faint lunar eclipse called a penumbral eclipse. Now, the more spectacular variety of lunar eclipses happens when the Moon passes through Earth's inner shadow, or umbra. That's when we see a dark "bite" taken out of the Moon, or in the case of a total lunar eclipse, a reddish, so-called "blood moon." Penumbral eclipses cause only a slight dimming of the Moon's brightness, so if you're not looking for it, you might not know there was an eclipse happening. But if you glance at the Moon early in the night, and then later, around the peak of the eclipse, you might notice the difference in brightness.

Even faint lunar eclipses like this one are always accompanied by a solar eclipse either a couple of weeks before or after. And on April 8th, a total solar eclipse will sweep across the U.S. (We'll tell you more about that in next month's video.)

There's a comet making its way into the inner solar system that's already observable with a telescope, and might start to become visible to the unaided eye by late March or in April. It’s a mountain of rock, dust, and ice several miles wide named 12P/Pons-Brooks.

It has a stretched-out, 71-year-long orbit that carries it as far from the Sun as the orbit of Neptune and nearly as close as the orbit of Venus. Fortunately, because this orbit is tilted, it doesn't cross our planet's path, so there's no chance of a collision.

Comet 12P has been observed on several of its previous appearances going back hundreds of years, and one thing it's known for is its occasional outbursts. Sometimes this comet suddenly brightens by quite a bit, due to bursts of gas and dust being released from beneath its surface. If this happens in the March-April timeframe as the comet nears the Sun, it could become bright enough to observe with the eye alone.

But even without additional brightening from outbursts, the comet is predicted to peak at a brightness that should make it easy to see with binoculars, and possibly just naked-eye visible under dark skies by the end of March.

Now, comets are notoriously unpredictable, so it's hard to know for sure how bright Pons-Brooks will get as it nears the Sun, but it's certainly worth a look. You can find it low in the west-northwest part of the sky at the end of evening twilight.

Comets, along with asteroids, are leftover pieces of the materials that formed the Sun and planets. So catch a comet and glimpse one of the building blocks of our solar system with your own eyes.

Here are the phases of the Moon for March. Stay up to date on NASA's missions exploring the solar system and beyond at science.nasa.gov. I'm Preston Dyches from NASA's Jet Propulsion Laboratory, and that's What's Up for this month.