Spectacular Tau Herculids meteor shower could light up North American skies

Spectacular Tau Herculids meteor shower could light up North American skies

Shattered Comet 73P/Schwassman-Wachmann 3

This infrared image from NASA’s Spitzer Space Telescope shows shattered comet 73P/Schwassman-Wachmann 3 brushing past a trail of debris left behind from its multiple trips around the sun. The flame-like objects are the comet fragments and their tails, while the dusty comet trail is the line connecting the fragments. Credit: NASA

Astronomers are excited about the possibility of another meteor shower on May 30-31, the Herculid tau shower, which is expected to peak on the night of May 30 and early in the morning of May 31.

In 1930, German observers Arnold Schwassmann and Arno Arthur Wachmann discovered a comet known as 73P/Schwassmann-Wachmann, or “SW3”, which orbited the Sun every 5.4 years. Being so faint, SW3 was not seen again until the late 1970s, looking fairly normal until 1995 when astronomers realized the comet had become about 600 times brighter and went from a faint stain to be visible to the naked eye as it passes. Upon further investigation, astronomers realized that SW3 had broken into several pieces, littering its own orbital trail with debris. When it passed through our path again in 2006, it was made up of almost 70 pieces and has been fragmenting ever since.

If it does reach us this year, debris from SW3 will hit Earth’s atmosphere very slowly, traveling at just 10 miles per second – meaning meteors much fainter than those belonging to the eta aquarids. But North American astronomers are taking particular note this year because the Herculid tau radiant will be high in the night sky at the predicted peak time. Even better, the Moon is new, so there won’t be any moonlight to wash away the faint meteors.

“It will be an all or nothing event. If the debris from SW3 was traveling over 220 miles per hour when it separated from the comet, we could see a nice meteor shower. If the debris had slower ejection velocities then nothing will happen to Earth and there will be no meteors from this comet,” said Bill Cooke, who directs[{” attribute=””>NASA’s Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

All the excitement from astronomers and the public has sparked a lot of information about the tau Herculids. Some has been accurate, and some has not.

We get excited about meteor showers, too! But sometimes events like this don’t live up to expectations – it happened with the 2019 Alpha Monocerotid shower, for example. And some astronomers predict a dazzling display of tau Herculids could be “hit or miss.”

So, we’re encouraging eager skywatchers to channel their inner scientists, and look beyond the headlines. Here are the facts:

  • On the night of May 30 into the early morning of May 31, Earth will pass through the debris trails of a broken comet called 73P/Schwassmann-Wachmann, or SW3.
  • The comet, which broke into large fragments back in 1995, won’t reach this point in its orbit until August.
  • If the fragments from were ejected with speeds greater than twice the normal speeds—fast enough to reach Earth—we might get a meteor shower.
  • Spitzer observations published in 2009 indicate that at least some fragments are moving fast enough. This is one reason why astronomers are excited.
  • If a meteor shower does occur, the tau Herculids move slowly by meteor standards – they will be faint.

Observers in North America under clear, dark skies have the best chance of seeing a tau Herculid shower. The peak time to watch is around 1 a.m. on the East Coast or 10 p.m. on the West Coast.

We can’t be certain what we’ll see. We can only hope it’s spectacular.

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