But we still can't be sure it isn't some sort of natural phenomenon.

No known conditions in space would support it as a natural phenomenon.

"No one has ever seen a problem like this, and it may very well turn out to be a natural phenomenon."

Fire is one of the most useful natural phenomena in the world.

Death is a natural phenomenon and the dead must be buried.

A natural phenomenon, you might say - but you'd be wrong.

Far more likely, you had accidentally come across a natural phenomenon.

How is it they make use of a natural phenomenon for their dirty work?

"You're beginning to think it's not a natural phenomenon after all."

A force of nature is a natural phenomenon that humans cannot control.

The warmer water, they say, could be a natural phenomenon.

Has this got you curious about any other natural phenomena?

We have developed new ways of seeing and representing certain natural phenomena.

They must have guessed by now that this was no natural phenomenon.

Are they natural phenomena or a message from the Divine?

And like many natural phenomena, lightning is not always what it seems.

It is also one of the most deadly natural phenomena known to man.

She is perhaps not related to a particular natural phenomenon like other gods.

If, that is, the gates were indeed built and are not, after all, a natural phenomenon.

These are all natural phenomena, and you should not use your position to bully others.

No natural phenomenon could be blamed for such a display.

Natural phenomena, such as a drop of water hitting a glass.

"Can you tell if this was caused by a natural phenomenon or a weapon?"

But, as the lights are a natural phenomenon, they cannot be guaranteed.

We must not get fishermen to foot the bill for natural phenomena.