Skip to content

Alex’s Space

alex banner

Insights from astrophysicist Dr. Alex Filippenko

Welcome to Alex’s Space! Here you’ll find the insights of Alex Filippenko, Professor of Astronomy at UC Berkeley. Alex was voted “Best Professor” at Cal a record 9 times. He has received numerous awards for his research and his outreach, including Wonderfest’s Carl Sagan Prize for Science Popularization. Alex was the only member of both teams whose research earned the 2011 Nobel Prize in Physics.

Perseid Meteor Shower, August 10-13, 2021

The annual Perseid meteor shower (arguably the best meteor shower of the year) will peak on the night of August 11/12 (Wed./Thur.), but the nights of August 10/11 (Tue./Wed.) and 12/13 (Thur./Fri.) should be pretty good as well. Some Perseid meteors will even be visible this weekend and next weekend.

View them after 11 pm local time — or better, after 12 am; the predawn hours should actually yield the largest hourly rate. [Before about 11 pm, few Perseids are visible (though they should be longer streaks than average, skimming through Earth’s atmosphere because the “radiant” from which they appear to come will be closer to the horizon).] Also, you don’t have to account for your specific *time zone* — the times I list above are fine *regardless* of where you are (though the northern hemisphere is much more favorable than the southern hemisphere, for this shower). The waxing crescent Moon will have set by the time most of the Perseids start appearing.

The meteor shower occurs because Earth flies through debris from Comet Swift-Tuttle, and the little bits of rock and ice will burn up as they zip through Earth’s upper atmosphere (altitude about 60 miles) at roughly 130,000 miles/hour.  (“Shooting stars” or “falling stars” are not stars at all, of course!) 

I encourage you to view the meteor shower, for at least half an hour (but an hour or longer is better). Try to get as far away from city lights as possible. The Perseids are known for having many bright and fast meteors that should be visible even in a somewhat light-polluted sky, though you’ll see many more from a darker location. *NO* binoculars or telescopes are needed; just look at the sky with your unaided eyes after getting dark-adapted (this can take up to 15 minutes). Choose a wide-open sky, without buildings or trees in the way. Dress warmly, and pack a hot beverage if you want to. Bug spray might be useful, too, depending on where you are. You should lie down on a mattress, sleeping bag, or reclining lawn chair for greater comfort, if you wish.

Looking anywhere in the sky is fine. Views to the northeast should provide the most meteors, though their streaks will be shorter than if you look elsewhere. If you have clear skies, you might see 1-3 dozen per hour. The meteor rate will be highest when viewed from the northern (not southern) hemisphere.

There are many useful references with additional information and viewing tips, etc.; type “Perseid meteor shower 2021” in your favorite search engine. See, for example,
and .