Nantucket astronomer Maria Mitchell always persevered. After many years of study, she discovered a new comet in 1847. It wasn’t easy, though. At one point in her search for that celestial body, she lamented, “I have worn myself thin trying to find out about this comet, and I know very little now in the matter.”

Though she may have been self-deprecating, we know that Mitchell was one of the premier astronomers of all times. It seems the past, as well as the future, may in several ways be female.

It is a lot easier nowadays to observe and learn about comets. Last weekend, one of these icy cosmic travelers provided us a close-up view. On Saturday, Feb. 11, a green comet, which goes by the name comet 45P/Honda-Mrkos-Pajdušáková, made the closest earth flyby of any comet in the last 30 years. Close is relative when you are speaking of comets: close, in this case, was 7.4 million miles away from our planet. For comparison, that is 30 times the distance to the moon.

If you missed it, as I did, there are some amazing photos and videos online. While comet 45P was not visible to the naked eye, it could be seen with binoculars and telescopes and, if you couldn’t get outside, it was live-streamed by Slooh, a community-based astronomy website.

Don’t despair if you didn’t observe it, as it will make another appearance. The “P” in its name means that it is periodic, so will come back around. In the case of 45P, it will pass the earth every five to six years, though last weekend was the closest it will be until the end of this century. Nor is it the only comet to watch for: 41P will be observable on April 1, 2017, and 46P will make itself known on Dec. 16, 2018.

Comet 45P is somewhat unique due to its color. This comet appeared green/blue. That hue resulted from the interaction of the comet and the sun. As it got closer to the sun, heat vaporized surface ice on the comet, thus releasing carbon-based gases. In the vacuum of space, those gasses glowed green.

Considered ‘leftovers’ from the dawn of the solar system, comets have always fascinated professional and amateur sky watchers. NASA describes them as “cosmic snowballs of frozen gasses, rock and dust, the size of a small town.”

Concerns have been raised about the possibility of a direct comet hit to the earth. Science fiction writer Isaac Asimov was able to enjoy the spectacle, putting aside this worry: “How bright and beautiful a comet is as it flies past our planet—provided it does fly past it.” While a collision could happen, most scientists agree that it is unlikely. NASA scientist Donald Yeomans, however, admits that a hit “would be a very bad day for Earth.”

The 45th periodical comet has safely passed us, but we are by no means out of trouble from another 45, the 45th president. “Perhaps British internet poet Nikita Gill provides a characterization of both by sharing this proclamation: “You are damaged and broken and unhinged. But so are shooting stars and comets.”

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature.