Is it really darkest just before dawn?

[Golem]

Well is it?

[karmgirl]

Don't know but that got me thinking.

Could you chase the sun when its going down so that it never gets dark. But then I suppose thats what you do when your on a plane to Austalia? :S

[New Judge]

A glimpse out of your window at around 5am today would have answered your question.

Dawn (sunrise) was at 5:14am today. At 5am it was almost broad daylight, it�s just that the sun was not above the horizon. Twilight began at about 3:30am and at just before dawn it was most certainly a lot less dark than it was at 1am � even allowing for the bright moon (waning, with about 65% illuminated).

I think (though I may be wrong) that the phrase is purely used to describe a sequence of events which appear to get worse before getting better.

Karmgirl�s unrelated idea is not so fanciful as it sounds. You can indeed �chase the sun� in an aircraft. Quite how fast you need to go to keep up depends on your distance from the equator. At the equator you would need to travel in excess of 1,000mph to avoid seeing the sun set. At higher latitudes this is much reduced. Concorde used to cross the Atlantic in 3 hours, although the time difference is 5 hours. So if you left London as the sun was setting you would arrive in New York two hours before sunset.

Unfortunately conventional aircraft are not fast enough and a journey to Australia, which takes about 24 hours, sees a time difference of only twelve. You delay the sunset if you travel westwards from the UK, but see it earlier if you travel eastwards.

[New Judge]

No I don't.

But the dog next door does!

[rov1200]

As our eyes are acclimatised to daylight then the shift to darkness takes a small amount of time. If you were in a dark room and stood still the surroundings will gradually get more visible as your eyes adjust.

[DrisgirI]

http://www.flickr.com/photos/28949361@N02/

[Azalian]

Astronomical twilight , the point in time when the night sky gets no darker begins when the sun is 18 degrees below the horizon and continues until the sun is 18 degrees below the eastern horizon on its way up.

From then on you will notice the eastern sky becoming lighter until the sun rises at dawn.

[Golem]

Thankyou to those who provided answers to the question. Much appreciated.

[lajohn]

http://math.ucr.edu/home/baez/physics/General/ BlueSky/blue_sky.html

[Zyzzyva]

People here are using 'dawn' to mean the same as 'sunrise.' I would argue that 'dawn' is the point at which the sky begins to lighten from the light of the sun. As some people have mentioned, the sky lightens long before the sun is actually seen, in which case--excluding moonlight and the varying brightness of stars--it would likely be darkest just before the dawn, as the last vestiges of dusk light would have faded, and dawn would not yet have begun to lighten the sky.

But I think the phrase is largely a metaphor for human suffering, rather than a scientific fact.