To admire the Perseids this Friday, this shower of shooting stars “which should rather be called shooting cometary dust”the astrophysicist Hervé Dole advises on franceinfo to settle “in a very dark area” and “after midnight”, “when the Earth faces its orbit”. “You will be able to observe several dozen per hour. Let’s say there will be one every 30 seconds, every minute, every two minutes”he promises.
franceinfo: Why do we always see shooting stars in August?
Herve Dole: It is a remnant of a comet traversed by the Earth at approximately the same place each year. So it falls each time around mid-August, even if there are other swarms in November or December. The one in August is the best known because it’s more outdoors, you can wear a t-shirt and it’s easier.
How tall are these Perseids?
These are very small particles of the order of a micron, a millionth of a meter. It’s really dust that was deposited by the comet a few years ago. And as our Earth comes at a very high speed in its orbit around the sun, these small particles are rushed through the atmosphere at absolutely tremendous speeds. They burn up at several thousand degrees in an instant and so we see these shooting stars. In fact, the term star is improper, one should almost say that they are shooting cometary dust.
How many shooting stars will we be able to see tonight if we sit down for an hour in our garden or in a park?
So already, if we are not careful, we may not see any at all. You have to be in a very dark area, rather in the second part of the night. After midnight, it will work much better since at that time, the Earth is facing its orbit and therefore the dust. You will be able to observe several dozen per hour. Don’t expect shooting stars like in Star Wars hyperspace. Let’s say there will be one every 30 seconds, every minute, every two minutes.
Is the full moon likely to spoil the show?
Yes a little bit because she is very bright. Moreover, it is an opportunity to see that the moon is yellow. In fact, it reflects the color of the sun and therefore has the property of lighting up the sky. So, we will still see a lot of shooting stars but actually, a little less than if the moon was not there tonight. Then it lasts a few days. The peak, indeed, will be this evening, but we can still observe two or three days before and after.