Only now are we descending from the top of the year for meteor enthusiasts: the Geminid meteor shower, which reached a prolific maximum of 60 to 120 meteors per hour on the night of December 13-14. But there is still another meteor shower to consider before closing the book in 2020: the Ursid meteor shower in December, which usually occurs during the night of December 21-22.
The bear cubs are so named because they appear to emerge from the vicinity of the bright orange star Kochab, in the constellation Little Bear, the little bear. Kochab is the brightest of the two outer stars in the Little Chariot ship (the other being Pherkad), which appear to march in a circle like sentries around Polaris, the North Star. But while Geminids are at the top of most meteorite observers to see the list, Ursids are usually at the bottom and are usually given little attention, except for the most assiduous meteorite observers. .
Related: Ursid 2020 meteor shower: When, where and how to see it
Often neglected
The fact that Kochab is positioned so close to the north pole of the sky means that it almost never settles for most viewers in the northern hemisphere. And since Ursidele seem to come out of this special region of the sky, it means you can look for these weak, medium-speed meteors throughout the night if you wish. And this seems like a reasonably good year to watch for them, as the moon in the first quarter will set around midnight on their peak night, making sure the sky will be dark for the second half of the night.
These meteors are best seen in the last dark hour before dawn, when the radiant is highest above the horizon in a dark sky. In the maximum morning, hourly rates between 5-10 urside can be observed. Diving through the Earth’s atmosphere at 22 miles (35 km) per second, Ursids produce mostly medium-speed meteors. Very little activity will be seen away from the night with maximum activity.
Ursids are a little-noticed shower in the northern hemisphere; the fact that observers neglected the bears is not surprising. Everything about them is winter. They usually coincide with the winter solstice and are best seen by polar bears because they come from near the celestial north pole.
The parent comet of the shower, where these meteoroids come from, appears to be 8P / Tuttle, which orbits the sun in orbit for 13.6 years and will return to the vicinity of the sun in August 2021. Occasionally, planet Earth has interacted with a current. narrow particle spilled by this comet, which caused short bursts of Ursid meteors in the tens of hours per hour, such as in 1945 and 1986; still others may have been missed because of the low weather or simply because no one bothered to look. Several lower rate improvements were reported between 2006 and 2008, which could have been influenced by the relative proximity of Comet Tuttle. Slightly improved rates found in the 2014 and 2015 video data indicate that trying to predict what this swarm of meteors could do in a given year is difficult.
Related: How meteor showers work (infographics)
Improved activity in 2020?
Several well-known meteorite experts have examined the orbit of Comet Tuttle and suggested that Earth may encounter some ancient dust trails thrown by Comet 8P / Tuttle, which could increase Ursid’s activity this year.
Esko Lyytinen and Peter Jenniskens predicted in the Meteorological Rainfall Calendar of the International Meteorological Organization in 2020 that the material thrown by the comet in 815 and 829 (about 1,200 years ago) could interact with Earth between 12:27 and 1:10 AM EST (0527 and 0610 GMT). Even earlier in the night, Japanese researchers Mikiya Sato suggest in the same document that the combination of two even older routes from 719 and 733 could affect our planet between 10:15 and 22:40 EST (0315 and 0340 GMT) on 21 December.
Unfortunately, all this material has been in space for about 13 centuries and has probably been widespread and will probably not provide a large increase in nominal rates of 5-10 hours per hour expected from urside.
However, if your sky is clear, you may want to go outside and check out the northern sky. This could be a good excuse to try to end the year on a positive note.
Hey, you never know.
Joe Rao serves as an instructor and guest lecturer at the Hayden Planetarium in New York. He writes about astronomy for the natural history magazine, the Farmers’ Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.