Update on a Possible Outburst of Meteors – Sky & Telescope


Meteor observing can be relaxing and enjoyable — and potentially dramatic. Yet the only equipment needed for serious meteor watching is your eyes and a modest amount of patience. Most of the annual meteor showers are fairly predictable, but the main attraction is that it’s impossible to predict what you will see. Occasionally you might be surprised by a dazzling fireball or the brilliant flash of a bolide.

A colorful Perseid fireball blazes during the 2016 shower. We’ll have to wait for the night of May 30–31 to see if the possible new meteor shower will produce similar fireballs . . . or any meteors at all.
Siaraduz / CC BY-SA 4.0

During the overnight hours of May 30–31 things might turn exciting.

In the fall of 1995, Comet 73P/Schwassmann-Wachmann 3 (SW3) fractured into several pieces and left a trail of fragments in its wake. Should the Earth encounter this stream of debris, a sudden outburst of meteors might erupt, ranking with some of our richest annual displays (Geminids and Perseids). There’s even a small chance that something extraordinary — perhaps a full-scale storm of meteors — might take place.

Or perhaps, visually, nothing at all will happen.

Meteor shower? Or not?

Astronomers worldwide have since investigated the prospects of Earth’s passage through this swarm of freshly ejected material. While some think no meteor shower of significance will take place on the night of May 30–31, others suggest our planet will have a direct interaction with the comet debris.

However, the occurrence of such a meteor shower or outburst requires a rather unique set of circumstances:

  • Typically, meteor showers are caused by tiny dust or sand-grain-size particles that trail behind a comet thanks, in part, to solar radiation pressure. But in this case the comet bits are probably larger: pebble- or nugget-sized.
  • When SW3 fractured, these larger particles may have been expelled at unusually high velocities. Such material would not be affected by solar radiation pressure and would tend to migrate forward of the comet’s direction of motion around the Sun, ultimately colliding with Earth. 

Unfortunately, such calculations are fraught with uncertainties. 

Comet 73P/Schwassmann-Wachmann 3 breaks up
The Hubble Space Telescope caught Comet 73P/Schwassmann-Wachmann 3 in the process of breaking up in 2006. As the top images show, the fragments themselves fragmented.
NASA / ESA / H. Weaver (JHU / AP) / M. Jäger / G. Rhemann

In the best-case scenario, it could result in a bevy of slow, bright meteors, glowing with a ruddy or orange tint, falling at the rate of dozens or hundreds per hour.

On the other hand, perhaps we’ll encounter very few comet particles — or maybe none at all. Another factor is that because the meteors will enter our atmosphere at a very slow speed — 16 km/s (36,000 mph) — they’ll be very faint or not visible at all to the naked eye. Since we’ve never encountered this swarm before, we can’t say for sure exactly what to expect.

When and where to look

If a display does materialize, meteors would appear to dart from a point several degrees northwest of the brilliant orange star Arcturus, in the constellation of Boötes, the Herdsman.

Radiant diagram for possible May 30th meteor shower
Should a meteor shower materialize on the night of May 30–31, they’ll appear to emanate from a point called the radiant, which is in the constellation Boötes.
S&T Diagram / Gregg Dinderman

The shower likely will last only a few hours. As to when it should reach its peak, for those in the Pacific Time Zone this should be around 10 p.m. on May 30th; for those in the Eastern Time Zone that translates to about 1 a.m. on May 31st. Sadly, for the Pacific Northwest, the twilight sky will probably be too bright, precluding a view of any possible display.

What do the pundits think?

To provide readers with the very best assessment as to what we might expect to see, we consulted a number of well-known meteor experts. 

Unfortunately, there’s no real consensus.

Two independent studies — one from Germany and the other from Japan — both confidently predict that significant meteor activity will result from the breakup of Comet SW3. 

But French meteor expert, Jérémie Vaubaillon of the Institut de mécanique céleste et de calcul des éphémérides (IMCCE) isn’t so sure: “I confirm that the shower is possible and plausible,” he writes, “but it is the level of the shower that is highly uncertain. We might see a storm, but frankly, we might also see a whole bunch of . . . not much!”

“This is going to be an all or nothing event,” comments William Cooke, manager of NASA’s Meteoroid Environment Office. “Personally, I remain skeptical that an outburst will occur. But I also could very well be wrong.”

Paul Wiegert of the Department of Physics and Astronomy at the University of Western Ontario registers a similar view: “I’ve quickly re-examined some of the modelling and don’t think the (comet) break-up could produce high enough speeds to reach Earth, but this process is very poorly understood . . . so as the song goes, ‘que sera sera.’ We just have to wait and see.”

In 1998, meteor astronomer David Asher developed a “dust trail” model of how meteoroid streams in space evolve. “There aren’t any previous examples for us to calibrate this year’s prediction,” he says, in anticipating what might happen this month. “An analogy with Biela’s Comet and the 1885 Andromedid storm might give us hope; also, the fact that comet SW3 underwent a major disruption at its 1995 return. If there’s an outburst, the meteors should be bright.”

A similar upbeat prediction comes from Russian dynamicist Mikhail Maslov who also predicts the meteors will be of “higher-than-average brightness.” He feels hourly rates could reach 600 to 700. “However,” he adds, “considering that in 1995 the comet broke into several parts, the real activity could be higher.”

So, will we see any meteors on the night of May 30–31? “We’ll soon know . . .” says comet fragmentation expert Zdenek Sekanina.

Good luck and clear skies!

For more information, see Contributing Editor Joe Rao’s article on page 34 in the May 2022 issue of Sky & Telescope.