⤵⤵⤵⤵⤵⤵⤵⤵⤵⤵⤵⤵ Prove that the earth is spherical
give 4 points
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Answers
1.Go to the harbor
When a ship sails off toward the horizon, it doesn't just get smaller and smaller until it's not visible anymore. Instead, the hull seems to sink below the horizon first, then the mast. When ships return from sea, the sequence is reversed: First the mast, then the hull, seem to rise over the horizon.
The ship-and-horizon observation is so self-evident that 1881's "Zetetic Astronomy," the first modern flat-Earth text, devotes a chapterto "debunking" it. The explanation relies on assuming that the sequential disappearance is simply an illusion brought on by perspective. This debunking does not make much sense, however, as there's nothing about perspective (which just says that things are smaller over longer distances) that should make the bottom of an object disappear before the top. If you'd like to prove to yourself that perspective isn't the reason for boats disappearing hull-first and returning mast-first, bring a telescope or binoculars on your trip to the harbor. Even with vision enhancement, the ship will still dip below the curve of the Earth
2.Look at the stars
Greek philosopher Aristotle figured out this one in 350 B.C., and nothing's changed. Different constellations are visible from different latitudes. Probably the two most striking examples are the Big Dipper and the Southern Cross. The Big Dipper, a set of seven stars that looks like a ladle, is always visibleat latitudes of 41 degrees North or higher. Below 25 degrees South, you can't see it at all. And in northern Australia, just north of that latitude, the Big Dipper just barely squeaks above the horizon.
Meanwhile, in the Southern Hemisphere, there's the Southern Cross, a bright four-star arrangement. That constellation isn't visible until you travel as far south as the Florida Keys in the Northern Hemisphere.
These different stellar views make sense if you imagine the Earth as a globe, so that looking "up" really means looking toward a different sliver of space from the Southern or Northern hemisphere.
Watch an eclipse
Aristotle also bolstered his belief in a round Earth with the observation that during lunar eclipses, the Earth's shadow on the face of the sun is curved. Since this curved shape exists during all lunar eclipses, despite the fact that Earth is rotating, Aristotle correctly intuited from this curved shadow that the Earth is curvy all around — in other words, a sphere.
For that matter, solar eclipses also tend to bolster the idea that the planets, moons and stars are a bunch of roundish objects orbiting each other. If the Earth is a disk and the stars and planets a bunch of small, nearby objects hovering in a dome above the surface, as many flat-Earthers believe, the total solar eclipse that crossed North America in August 2017 becomes very difficult to explain.
Go climb a tree
This is another one of those self-evident things: You can see farther if you go higher. If the Earth was flat, you'd be able to see the same distance no matter your elevation. Think about it: Your eye can detect a bright object, like the Andromeda galaxy, from 2.6 million light-years away. Seeing the lights of, say, Miami from New York City (a distance of a mere 1,094 miles or 1,760 kilometers) on a clear evening should be child's play.
But it's not. That's because the curvature of the Earth limits our sight to about 3.1 miles (5 kilometers) … unless you climb up a tall tree, building or mountain and get yourself a perspective from higher up.
Answer:
1. Watch a ship sail off to sea
Without being in the sky, it is impossible to see the curvature of the Earth. However, you can always see a demonstration of this if you visit a harbor or any place with a wide-open view of the water.
If you are able to watch a ship sail off to sea, watch its mast and flag as it fades off into the distance. You will notice that, in fact, it does not "fade off into the distance" at all; instead, you will see its mast and flag appear to slowly sink. The ship sailed beyond the point at which you would see it. Just to be sure, bring a pair of binoculars with you so that you can see even farther off into the distance.
It's as if you're watching it go over to the other side of a hill. This phenomenon can only be explained by a sphere-shaped planet.
2. Watch a lunar eclipse
Solar eclipses get all the attention, but if you are able to catch a glimpse of a lunar eclipse, you can see evidence that the Earth is, indeed, round. Here's how it works: Earth passes between the moon and sun, so that the sun projects Earth’s shadow onto the Moon in the night sky. You've probably seen a partial lunar eclipse without even noticing it; if the moon looks orange, that's a sign of a lunar eclipse. If you've ever seen a total lunar eclipse, you probably noticed that the shadow did not look like this.
A round shadow crossed over a round object. This does not sound like a thing that would happen if we were on a plane with all of the celestial bodies simply hovering overhead—or, perhaps more assinine, if the sun were orbiting Earth and not vice versa. The last total lunar eclipse took place on January 31, 2018, but it was not visible in most of the United States. Fear not, as you only have to wait a few months for one that will be visible in the Americas on July 27, 2018.
3. Climb a tree
Imagine a vast plane with but one tree smack in the middle. If the earth were flat, your vision would extend exactly as far while standing at the base of the tree as it would when at the top of the tree. However, the farther you climb, the farther your line of sight will extend to the horizon.
That's because parts of Earth that were concealed from view by its curvature are now revealed because your position has changed.
Back to the vast plane. The naked eye can see objects that are millions of miles away in space. Theoretically, with a clear line of sight on a clear night, one would also be able to see bright lights from far-away cities. That this is not possible is further evidence of a round, not flat, Earth.
4. Travel through, or even within, different time zones
According to a 2008 paper in Applied Optics by David K. Lynch, the curvature of the earth becomes somewhat visible at an elevation of 35,000 feet (with a >60° field of view) and more easily visible at an elevation of 50,000 feet. So if you're on the right commercial flight, you might be able to see the curvature of the earth with your own two eyes.
In the event that you're not high enough, though, you can still experience the curvature of the earth another way. For example, if you were to fly all the way around the world, you'd find that it would be nighttime in part of the world and daytime in another part. In that way, the existence of time zones itself is proof that the Earth is round.
Taken another way, you wouldn't even need to travel through different time zones. Time zones are wide enough that you will see the sun rising and/or setting later in the western part of a time zone than in the eastern part. According to the Farmers' Almanac, the sun will rise and set roughly four minutes later for every 70 miles you drive from east to west.
If you wanted to combine this experiment with the previous one, you could note how much more of Earth you can see when you begin your ascent into the air than you can while you are sitting on the tarmac waiting to take off.