No electromagnetic signal travels straight through the atmosphere, except during the
rare conditions when the atmospheric refractivity is the same at every altitude. Since
the refractivity depends on the temperature, humidity, and pressure of the air, you can
imagine how rarely that quantity is constant with altitude.
When refractivity changes with altitude, the path taken by a beam of radio or light curves
as it proceeds along its path. The exact nature of the curve depends on exactly how fast
the refractivity changes with altitude at the time. Occasionally but not often, it curves up
from a straight path. Most often, it curves down from a straight path, anywhere from slightly
to drastically. It doesn't necessarily follow the curve of the earth's surface. Most often, the
earth curves down faster than the signal does. It's possible for the signal to curve down
exactly as fast as the earth does, and its path remains parallel to the surface. Occasionally,
the signal curves down faster than the earth's curvature, and it returns to the ground some
distance from the antenna or the flashlight where it started. That situation happens more
often in desert regions, where the ground cools rapidly at night. Since the human eye and
brain believe that an object is located in the direction from which its image comes, these
atmospheric conditions in the desert lead to sightings of oases in the sky and other 'mirages'.
It's no accident that the legends of flying horses and magic carpets originated in the harshest
deserts.
As you may have noticed, this stuff fascinates me. Thanks for the question.
... is called a Great Circle arc.
Technically, No. Water in a glass (or other vessel) has a curved surface known as a meniscus. A large body of water (like an ocean) actually follows the curve of the earth. So the surface of the water is a curve or section of a sphere.
No. Level flight for an aircraft is not flight in a straight line (vertically) but one that follows the curvature of the earth. It is an arc that maintains the same altitude.
Axis
Not from the land as light travels straight, and there are too many obstacles within our line of sight. But it is possible to realise it from heights in a plane or on a mountain. You will see that there are no conrners, which means it is a curve as it is not a line. Absolutely yes. The best places to see the curve of the earth is on the shore or on the ocean. It is possible to see it in the arch (although ever so slight) in long spanning suspension bridges, where the vertical bridge supports are not parallel. Other places on land is flat areas like Kansas or the desert where you can get a horizon to horizon view. On cloudy days, you can see the wrap of atmosphere as the distance to the horizion increases but the humidity has to be low for this to occur.
They curve with the curve of the Earth.
it is the ORBIT, I think...
it is the ORBIT, I think...
ducting
The answer is 8km/s
A great circle
Global winds are caused by unequal heating of the Earth's surface and they curve because... If the Earth did not rotate, Global Winds would not curve. They would be straight as a line. So because of EARTH'S ROTATION, global winds curve.
No electromagnetic signal travels straight through the atmosphere, except during the rare conditions when the atmospheric refractivity is the same at every altitude. Since the refractivity depends on the temperature, humidity, and pressure of the air, you can imagine how rarely that quantity is constant with altitude. When refractivity changes with altitude, the path taken by a beam of radio or light curves as it proceeds along its path. The exact nature of the curve depends on exactly how fast the refractivity changes with altitude at the time. Occasionally but not often, it curves up from a straight path. Most often, it curves down from a straight path, anywhere from slightly to drastically. It doesn't necessarily follow the curve of the earth's surface. Most often, the earth curves down faster than the signal does. It's possible for the signal to curve down exactly as fast as the earth does, and its path remains parallel to the surface. Occasionally, the signal curves down faster than the earth's curvature, and it returns to the ground some distance from the antenna or the flashlight where it started. That situation happens more often in desert regions, where the ground cools rapidly at night. Since the human eye and brain believe that an object is located in the direction from which its image comes, these atmospheric conditions in the desert lead to sightings of oases in the sky and other 'mirages'. It's no accident that the legends of flying horses and magic carpets originated in the harshest deserts. As you may have noticed, this stuff fascinates me. Thanks for the question.
Microwave EM radiation travels only in a straight line - line-of-sight/point to point. Bouncing waves off of the ionosphere would accomplish this.
Light and radio signals seldom travel in straight lines through air, because the pressure, temperature, and density of air change with altitude. Light and radio signals almost always curve vertically, and usually downward. If you were to draw a picture of the real earth's surface, with the real path of a light beam or radio signal traveling above it, the surface of the earth would curve downward on the drawing, and the light or radio signal would also curve above it. The distance between the surface and the light or radio signal would change across the drawing, depending on how strongly the signal curved, and in which direction (up or down). It would be possible to distort the drawing in such a way as to make the light or radio signal appear to be a straight line. In order to do that, you'd have to change the curvature of the earth's surface on the drawing, and maintain the original spacing between the surface and the radio signal at every point. The number by which you have to multiply the true earth radius in order to make the light or radio signal's path appear straight on the drawing, is the "effective earth radius factor". It's a characteristic of atmospheric conditions (specifically, the vertical gradient of the atmosphere's index of refraction), and it's used in designing the optimum physical configuration of point-to-point radio links, i.e. how high above the ground to mount the antennas at each end of the link.
inertia makes it want to fly straight but gravity makes it curve
... is called a Great Circle arc.