Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 August 7
The featured image shows a bright green meteor trail
crossing before the distant Andromeda galaxy. 
Please see the explanation for more detailed information.

Meteor before Galaxy
Image Credit & Copyright: Fritz Helmut Hemmerich

Explanation: What's that green streak in front of the Andromeda galaxy? A meteor. While photographing the Andromeda galaxy in 2016, near the peak of the Perseid Meteor Shower, a small pebble from deep space crossed right in front of our Milky Way Galaxy's far-distant companion. The small meteor took only a fraction of a second to pass through this 10-degree field. The meteor flared several times while braking violently upon entering Earth's atmosphere. The green colour was created, at least in part, by the meteor's gas glowing as it vapourized. Although the exposure was timed to catch a Perseid meteor, the orientation of the imaged streak seems a better match to a meteor from the Southern Delta Aquariids, a meteor shower that peaked a few weeks earlier. Not coincidentally, the Perseid Meteor Shower peaks later this week, although this year the meteors will have to outshine a sky brightened by a nearly full moon.

Tomorrow's picture: celestial lagoon


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