Space & Astronomy
Exploring "Why" questions about Space & Astronomy
480 articles
why are there two high tides in a 24h period when the earth rotates once?
Because the tides are high when the moon is directly above, or directly on the other side of the world, and lowest when it's 90 degrees to that. This [image](_URL_0_) might help. Obviously, you have t
Why can’t the number of stars in the Milky Way determined to a greater degree of precision? Even though estimates don’t span across orders of magnitude, 200M to 400M still *seems* to be quite a wid…
First of all, its estimated at around 400 billion, not 400 million. Second, due to the shape of the galaxy, we cannot see the stars that are hidden behind the center of the galaxy. Thus, we have to gu
why do posts on here have to start with “ELI5”?
Because people who subscribe to ELI5 have the posts peppered into the rest of their front page and feed, so seeing "Why does a high gear produce less power than a low gear?" in your feed along with r/
Why do people tell you to not mix alcohols? I’ve always been told that if I’ve started with vodka, I should stick with vodka for the rest of the night and am not sure why.
It is a myth. But if you stick to one kind of drink you may be better able to judge how much you have consumed. It takes a loading dose of alcohol to saturate the alcohol modifying enzymes.
Why ketchup bottles are typically clear while mustard bottles aren’t.
Most commerically sold mustard has a preservative called Preservative 202, which is not present in ketchup. When the preservative comes in contact with a plastic bottle for an extended period of time
Why aren’t NASA using plans of Apollo mission vehicles to return to the moon?
The Ford Model T worked perfectly well in the 1900-1930's, we could dig out the plans and make another now.. It's more than a question of cost, but of capability. Since the 60's portable computing pow
Why do I start crying when I’m angry?
I'm no scientist, but I did watch a youtube video about [this](_URL_0_), and it explains it very well. Basically, we cry when we expirience a loss of control or are under heavy stress. Tears are a way
Why does our atmosphere appear blue from earth in sunlight, but when earth is viewed from space also in sunlight, it’s clear/invisible?
The sky appears blue from inside our atmosphere because the light refracts (bounces around). The blue part of the light bounces around more, so that's what we see. From the outside however, we're seei
Why would a company like Mars modify one flavor of a candy like Skittles and then refuse to go back to the old flavor in the face of monumental backlash?
"Monumental backlash" often is nothing more than a vocal minority complaining loudly and often about something they don't like. Those people are also likely to continue buying the product in spite of
Why do concerts generally start so late?
Liquor, liquor, liquor. The longer you wait the more booze you are likely to buy. This applies to all concessions, but the markup on booze is particularly fruitful.