Surviving records identify it as an astronomical and historical phenomenon.

Once an astronomical phenomenon is detected, they noted, other observers know what to look for and are likely to find more examples.

The cloud was a most rare and strange astronomical phenomenon, from what we know today.

In this section you can learn about the origins of the universe, black holes and other astronomical phenomena.

Nor did certain of the more obscure astronomical phenomena escape his attention.

Summer solstice is the astronomical phenomenon that occurs on the longest day of the year.

There are a few hypotheses being considered to try to explain this astronomical phenomenon.

The name of the competition comes from the astronomical phenomenon known as an aurora.

This unusual astronomical phenomenon takes place in a pattern that repeats itself every 243 years.

That's why we don't think it was any known astronomical phenomenon.