Stargazers ready for rare visit from two-tailed comet
But if galactic traveller can’t hold itself together, there is plenty more to see
The pandemic is wreaking havoc on this planet, but the rest of the solar system is humming along blissfully unaware of events on the third rock from the sun, even putting on the year’s best night-sky show this month.
Comet NEOWISE is making a once-in-a-lifetime visit from outside the solar system — its hyperbolic trajectory took it past the sun on July 3, making it visible again in the pre-dawn sky and highlighting its two tails. Named after the Nearearth Object Wide-field Infrared Survey Explorer space telescope through which it was discovered on March 27, in the coming days Comet NEOWISE will start to be visible at dusk.
Maybe.
Earlier comets ATLAS and SWAN disintegrated instead of brightening, leaving star gazers disappointed. Predicting comet behaviour has been compared to predicting what a cat will do next.
“It’s visible in the early morning sky to the naked eye an hour or so before sunrise, and you can definitely see it with binoculars,” said Joanna Woo, an astrophysicist at SFU and director of the Trottier Observatory.
“It’s supposed to move toward the evening sky in the next few days, but comets are unpredictable, so you will want to look now.”
Added Rachel Wang, an astronomer at the H.R. Macmillan Space Centre: “You definitely want to see it sooner rather than later because we did have Comet ATLAS in December of last year and everyone was excited. It was a similar story, it was going to be great. But it ended up fragmenting, breaking up before it got close to Earth.”
Assuming NEOWISE holds itself together, it will continue to brighten as it approaches.
A comet’s brightness is ranked by a magnitude scale; the lower the number, the better.
The sun, for example, has a magnitude of minus-27, the full moon minus-13, according to Comet Watch. Venus, usually the brightest planet in the sky, has a magnitude of minus-3.7 to minus-4.5.
NEOWISE has a magnitude between 1.0 and 2.0, Wang said.
Saturn will follow Jupiter like a good subordinate all night across the western sky, Mars and the moon will cross paths this weekend, beginning next week Venus and Mercury will align with a waning crescent moon just before dawn, and Venus will shine next to bright Aldebaran, a first-magnitude star.
“It’s the best month to look at Jupiter and Saturn because they are going to be the closest to us they have been in a while,” Wang said.
The yearly Perseids meteor shower will appear from July 17 to Aug. 24, peaking around Aug. 11-12.
NEOWISE, however, won’t be back for some 6,800 years.