Naked Science Forum

General Science => Question of the Week => Topic started by: matthewh on 15/07/2019 13:35:28

Title: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?
Post by: matthewh on 15/07/2019 13:35:28
Manik has asked us...

Can you tell from a painting or a photo, if it's a sunrise or a sunset?

Help us sun-SET the record straight by sun-RISING up with some answers
Title: Re: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?
Post by: chiralSPO on 15/07/2019 14:22:30
Well... the easiest way is if there are obvious landmarks that allow one to recognize whether the sun is in the East or West.

I would also expect there to be subtle but detectable differences in the images, because sunrises and sunsets aren't exactly the same. When sunrises occur, it is much colder than when sunsets occur, so the corresponding differences in atmospheric properties might induce some very small changes in how the light disperses.
Title: Re: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?
Post by: evan_au on 16/07/2019 12:23:30
Quote from: chiralSPO
if there are obvious landmarks
I recently attended an art exhibition featuring Monet's painting "Impression, Sunrise", which gave its name to the whole Impressionist movement.

The exhibition included a careful analysis of the landmarks half-visible in the misty scene (or, more likely, a steam-powered smog...).
...or they could have just read the title!
See: https://nga.gov.au/impressionsunrise/
Title: Re: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?
Post by: Bored chemist on 16/07/2019 13:21:33
To the limited extent that moss grows on the North side of trees...
( I think you get a self cancelling error if you are in the other hemisphere)
Title: Re: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?
Post by: alancalverd on 16/07/2019 17:22:37
If it's a UK beach scene, there's only one west-facing beach on the east coast (Hunstanton), which shortens the odds a bit.
Title: Re: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?
Post by: evan_au on 17/07/2019 12:36:14
Quote from: OP
Can you tell from a painting or a photo, if it's a sunrise or a sunset?
Most modern cameras embed a time and date stamp in the EXIF metadata of a digital photo.
- Smartphones even embed the GPS coordinates
- In theory, they could even record the magnetic sensor reading, so you know which way the camera was facing when the picture was taken....
- Of course, this could be misleading if the camera never had the date and time configured, or if the user traveled to the other side of the world without changing the timezone!

...just such information cost the US military millions of dollars when some photos of some new helicopters at a middle-east airbase were posted on social media - and used to target mortar rounds...
Title: Re: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?
Post by: Zer0 on 23/09/2019 21:28:19
Maybe the local vegetation or nature's greens might provide a clue..." Phototropism " or maybe the unequal breakdown of " Auxins "...

But perhaps the most easiest way would be to read the captioning on the canvas or image of the painter or photographer and believe they are being truthful.
;)
Title: Re: QOTW: 19.07.15 - Can you tell between a sunrise or sunset in a picture?
Post by: Hayseed on 10/10/2019 08:40:40
If you can orientate the image, the shadows can tell you the time.