FACT 3 There is an approximate repeat of orbit tracks over the same area on the ground every 3 days. Again, the ISS altitude will determine how closely the tracks repeat.
FACT 4 The part of the Earth visible to ISS astronauts in daylight changes due to the interaction between the orbit patterns of the station and the rotation of the Earth. The daylight portion of the orbits shifts slightly eastward along track each day. This lighting procession follows an approximate day cycle from a descending track covering the mid-latitudes, to southern hemisphere lighting, to ascending tracks, to northern hemisphere lighting. Queen of the Night: Classy Cassiopeia Constellation Reigns Over Meteor Photo The constellation Cassiopeia, named after a mythical Greek queen who boasted about her beauty, can also be seen on the right of the image.
There have been no observed collisions between natural satellites of any Solar System planet or moon. Collision candidates for past events are: The objects making up the Rings of Saturn are believed to continually collide and aggregate with each other, leading to debris with limited size constrained to a thin plane. A satellite maintains its orbit by balancing two factors: its velocity the speed it takes to travel in a straight line and the gravitational pull that Earth has on it.
A satellite orbiting closer to the Earth requires more velocity to resist the stronger gravitational pull. What makes the ISS shine? There are no bright lights on the outside of the space station. Much of the ship is light-colored. The station will begin its flyby over Central Florida at around , appearing over the southwest horizon. It will move to the northeast, visible for about 6 minutes. That means at around p. The space station is visible because it reflects the light of the Sun — the same reason we can see the Moon.
It can only be seen when it is dawn or dusk at your location. Look about 30 degrees above the horizon to start, he said. Look to the northwest, under the Big Dipper, with binoculars if possible.
The comet should be right below that constellation, low on the horizon just after sunset. Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Social studies Why are orbital paths curved? Social studies.
Ben Davis February 20, Why are orbital paths curved? The equator of the earth appears as a straight line in both pictures. Also keep in mind that this is a simplification of different projection methods used and only explains why the orbit seems to look like a sine-wave. In reality more complex projection methods are used. An orbit takes place on a single 2d plane, through the center of the planet.
A sphere and a plane through its center intersect in a circle. See diagram:. There is no actual sine wave movement going on, the ISS moves around the planet above the red line, in a circle. The apparent sine motion of the ground track is entirely due to the Mercator projection being used when the map is 'unfolded' from globe to flat surface. Hopefully this image allows you to more easily see the projection, note how the red line "curves downwards" at the front of the image, crosses the equator, and goes up around the back of the sphere.
When the checkerboard surface is stretched out into a 2d grid, the red line gets stretched out to be a sine. Note that the sinusoidal motion is also due to the orbit being almost circular. If the orbit was a highly eccentric ellipse, like this:. This is very useful for observing the ground in the northern hemisphere, since the satellite spends a lot of time in that hemisphere. Going to even further extremes, the ground track of a geosynchronous satellite is a point.
For something nearly in geosynchronous orbit, you can get figure-8 ground tracks. See pp. The answer is harmonic motion and circular motion. You have just rediscovered what Galileo Galilei found in , so you may well be on a good way to other discoveries - good luck! Bear in mind that the orientation of an axis of rotation or of an orbit is essentially fixed in space. This means that there is a fixed relationship between the ISS orbit and the Earth's polar axis. Its orbital plane must be centered on Earth's center of mass; as it happens, the ISS orbit is inclined with respect to the Earth's equator the ISS orbital parameters are by design , so the ISS ground track will appear to move up and down across the equator.
For what it's worth: the track shifts from orbit to orbit because the Earth has moved rotated under it. The track doesn't undergo seasonal change because neither the Earth's axis nor the ISS orbit change with the seasons.
What changes through the seasons is the Sun's aspect relative to the Earth due to Earth's axial tilt relative to its orbital path around the Sun. The key point is how I introduced my answer - the ISS orbit is fixed in its relationship to Earth's axis, which is all that matters for this question. Sign up to join this community. The best answers are voted up and rise to the top.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why does the ISS track appear to be sinusoidal? Ask Question. Asked 5 years, 1 month ago. Active 7 days ago. Viewed 13k times.
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