Have you ever wondered how/what/where/why?

[Quadman2]

The other day, I had a what I thought was a really simple question. But, after asking quite a few people, I discovered they didn't know the answer to this question either! After seeing a huge, some call it a "Hunger Moon" at 7:00 AM hanging in the morning sky, I thought...'I wonder why that bloody big thing doesn't slam into the earth? It looks like it could right now'. So, I went to google, and found that it was a tricky, a not simple answer that I expected to find. Even now, I'd have difficulty explaining this to some one. But, if any one can break it down into simple terms, I'd be obliged.

In turn, Ill bet there's a million questions out there that defy explanation, but I also wager that there's people with a knowledge base that can offer some sort of answer many of the every day encounters of, ' I wonder h/w/w/w/w? There was a TV series that dealt with "How Things Work" and found it fascinating.

It probably be best to keep the intent of this thread away from contentious subjects like religion/politics/ethics. These types of questions tend to create two camps of thought that become polarized. We are here to share, not judge!

Th inquiries could be of scientific/natural/everyday/etc. events/happenings/things.

So, if some one could step into the circle and explain this "moon" thingy, I'd appreciate it.

Take care all, and have some serious listening this coming weekend.

Q

 

[JDub]

So, if some one could step into the circle and explain this "moon" thingy, I'd appreciate it.

I'll have a go at it:

So the moon is poised above the earth, is subject to gravity and so falls towards the earth at a certain speed*. But the moon also has its own forward velocity, so it moves at right angles to the direction it’s falling in at its own speed. For a short period of time, you could approximate this motion by drawing a line towards the center of the earth and another line at right angles to it, with the lengths of the lines representing distance traveled in an arbitrary time interval. Now if you draw in the hypotenuse of this right-angled triangle, that line represents the moon’s net travel in that time interval. Repeat this operation, keeping in mind that forward motion for the second triangle is in the direction of the hypotenuse of the first triangle, and the direction towards the center of the earth is still at right angles to that line. Something like this:







Where blue lines are “Forward” green lines are “Down” and the red lines represent net travel.

So if you repeat this enough times, you end up back where you started and get a polygon centered on the center of the earth. If you repeat this whole exercise with shorter time intervals, the lines are shorter and it takes more steps to get back to the beginning. If the time interval is essentially zero (infinitesimal, in math-speak) then the line lengths are also essentially zero and it takes an infinite number of steps to get around, at which point the polygon becomes (mathematically) a circle, or (physically) an orbit.

* Actually acceleration, but since it’s accelerating from one point to another, it has an average speed.

I hope this makes some sort of sense, and ideally is simpler than your Google result.

 

[teal'c]

Simple?
Gravity pulls it in with approximately the same force that speed throws it out.

 

[Mr.Jim]

Yeah, and what kind of cheese is it made of?

 

[teal'c]

moonzzarella

 

[toxcrusadr]

Even more interesting than the orbital mechanics (to me anyway) are questions like, why is our moon so much bigger in comparison to the Earth than other moons in the solar system? Why do we have only one big one, when Mars has two, Jupiter has a bunch, etc.? Why is the moon just about the same apparent size as the Sun so that solar eclipses are just about perfect? What a happy accident that was. Was the moon always that far away? Will it always be that far away or will it get farther or closer in the future?

I've heard some answers and theories on these questions on some of the science network shows about the solar system. Really fascinating stuff is being learned and tested all the time on the history of the solar system.

 

[nj pheonix]

Think of the moon as a yoyo.
Think of the earths gravity as the string.
Think of yourself as the earth.
If you swung the yo yo on the string and it didn't wind up on its shaft or your finger it would continue around forever (except for wind resistance, friction and really gravity (it own weight) pulling on it.
If you cut the string, it would fly off.
If it were swung too slowly it would start to fall to you.
There's a balance to the speed and it staying out and the gravitational force pulling on it.
An equilibrium if you will.

 

[Mr.Jim]

I think it is government cheese. The shuttle brings it back, and the government packages it as government cheese for fema distribution.

 

[toxcrusadr]

Why is our moon so big?

"The vast difference stems from how the moons formed. The other planets in the solar system used gravity to capture free floating bodies. But, Earth's moon was created when a Mars-sized body slammed into the young planet. Gravity captured the debris as it splayed into space and over time, the material eventually congealed into a satellite."

How important our large moon is to stabilization of climate and therefore to the development of life on Earth:

https://www.space.com/12464-earth-moon-unique-solar-system-universe.html

"The moon has long been recognized as a significant stabilizer of Earth's orbital axis. Without it, astronomers have predicted that Earth's tilt could vary as much as 85 degrees. In such a scenario, the sun would swing from being directly over the equator to directly over the poles over the course of a few million years, a change which could result in dramatic climatic shifts."

https://www.space.com/12464-earth-moon-unique-solar-system-universe.html

The moon's size also creates fairly large tides, which led to a wide zone along the seacoasts where water ebbs and flows, creating a transitional habitat where important life stuff can take place.

The moon is actually spiraling away from Earth very slowly - a couple inches per year. So it was closer (and visually larger) in the past. The tidal pull of the Moon is also slowing Earth's rotation, so that, far in the future, the same side will always face the moon, and a day will be a month long. How weird is THAT.

https://www.spaceanswers.com/solar-system/exiled-asteroid-found-in-the-kuiper-belt/

 

[teal'c]

Why is the moon just about the same apparent size as the Sun so that solar eclipses are just about perfect? .

Because the moon's size was determined by holding a US quarter at arms length.

 

[toxcrusadr]

See now that's the kind of science I come to AK for.

 

[usedto]

Because the moon's size was determined by holding a US quarter at arms length.

With all due respects to gender equality, it may have been a Susan B Anthony dollar.

 

[onwardjames]

I was primed and ready to answer about the moon (which is leaving us at around 4 centimeters a year or some small amount) and will eventually float away, but looks like tox has it all covered.

I love science. Basically, science is an agreed-upon hypothesis or theorem of the greatest minds on Earth, continually subject to new data and scrutiny.

Brother, if that isn't close enough, it works for me. A self-correcting ship, science is (of course, when not subject to monies and premeditated outcomes).

The scientific method works wonderfully.

 

[ETLS]

And why did teal,c jump over the moon in the first place?

 

[Quadman2]

Simple?
Gravity pulls it in with approximately the same force that speed throws it out.

True, to a point. But I believe that there are TWO gravitation forces at play here. the inward and the sideways one as well. This is where it gets...difficult.

JD, I am going to have a serious take on your explanation. I did not so good in trig, and first year calculus was even more steep on the learning curve.

Thanks for the input.

Q

 

[teal'c]

Only two? Might want to rethink that. Earth, moon, and sun, three gravitational forces to start, then factor in multiple inertial forces...

 

[thilaseen]

Because the moon's size was determined by holding a US quarter at arms length.

The real question is....how long is an arm?

 

[PanheadXR290]

I wonder often how we got from V2 rockets to the moon in 15 years but haven't been to Mars yet when more than 1 rocket scientist says we can go to Mars now using existing tech ,but im not an aeronautical engineer so I'm blissfully ignorant .

 

[Judas Priest]

I think space travel is just a matter of money, not technological limitations.

 

[Nightcleaner]

I had a silly moment the other day fortunately leave in a town with a lovely beach. Was thinking about that wet stuff that comes in goes out come in goes out all day. Was thinking how old is it? is it the same water that comes in goes out comes in goes out. Does it ever get replenished

Ah well back to reality