# What are the laws that govern the motions of planets?

## What are the laws that govern the motions of planets?

Kepler’s Laws of Planetary Motion They describe how (1) planets move in elliptical orbits with the Sun as a focus, (2) a planet covers the same area of space in the same amount of time no matter where it is in its orbit, and (3) a planet’s orbital period is proportional to the size of its orbit (its semi-major axis).

What is Kepler’s third law formula?

Kepler’s Third Law Equation 13.8 gives us the period of a circular orbit of radius r about Earth: T = 2 π r 3 G M E . T = 2 π r 3 G M E . For an ellipse, recall that the semi-major axis is one-half the sum of the perihelion and the aphelion.

What are Kepler’s 3 laws in simple terms?

There are actually three, Kepler’s laws that is, of planetary motion: 1) every planet’s orbit is an ellipse with the Sun at a focus; 2) a line joining the Sun and a planet sweeps out equal areas in equal times; and 3) the square of a planet’s orbital period is proportional to the cube of the semi-major axis of its …

### What has an eccentricity of zero?

If the eccentricity is zero, the curve is a circle; if equal to one, a parabola; if less than one, an ellipse; and if greater than one, a hyperbola. See the figure.

What is eccentricity formula?

Eccentricity Formula The formula to find out the eccentricity of any conic section is defined as: Eccentricity, e = c/a. Where, c = distance from the centre to the focus. a = distance from the centre to the vertex.

Why is a circle’s eccentricity 0?

A circle is an ellipse in which its two foci coincide with its center. So, for a circle the distance from the center to a focus is zero (since they are the same point). For this reason the eccentricity if a circle is zero.

## What is the eccentricity of Earth?

Earth’s orbital eccentricity e quantifies the deviation of Earth’s orbital path from the shape of a circle. It is the only orbital parameter that controls the total amount of solar radiation received by Earth, averaged over the course of 1 year. The present eccentricity of Earth is e ≈ 0.01671.

Does eccentricity affect climate?

Eccentricity measures how much the shape of Earth’s orbit departs from a perfect circle. These variations affect the distance between Earth and the Sun. Because variations in Earth’s eccentricity are fairly small, they’re a relatively minor factor in annual seasonal climate variations.

How is Earth’s eccentricity calculated?

The formula to determine the eccentricity of an ellipse is the distance between foci divided by the length of the major axis.

### Is Earth really eccentric?

The eccentricity of the Earth’s orbit is currently about 0.0167; the Earth’s orbit is nearly circular. Even further out, Sedna, has an extremely high eccentricity of 0.855 due to its estimated aphelion of 937 AU and perihelion of about 76 AU.

What does high eccentricity look like?

Scientists use a special term, “eccentricity”, to describe how round or how “stretched out” an ellipse is. If the eccentricity of an ellipse is close to one (like 0.8 or 0.9), the ellipse is long and skinny. If the eccentricity is close to zero, the ellipse is more like a circle.

How often does eccentricity occur?

Eccentricity describes the degree of variation of the Earth’s orbit around the Sun from circular to more elliptical. Eccentricity has two main periodicities, one cycle with an average of ~100,000 years and a longer cycle with a periodicity of ~413,000 years.

## How does eccentricity cause ice ages?

These fluctuations include changes in the shape (eccentricity) of Earth’s orbit, the tilt (obliquity) of Earth’s axis, and the wobbling (precession) of Earth’s axis. When the orbit is more elliptical, glaciation is affected by the time of year (season) that Earth is closest to the sun.

Is Earth’s tilt changing?

Earth’s obliquity oscillates between 22.1 and 24.5 degrees on a 41,000-year cycle. Over the course of an orbital period, the obliquity usually does not change considerably, and the orientation of the axis remains the same relative to the background of stars.

What if the Earth’s tilt was 10 degrees?

If the Earth’s tilt were at 10 degrees instead of 23.5 degrees, then the Sun path through the year would stay closer to the equator. So the new tropics would be between 10 degrees north and 10 degrees south, and the Arctic and Antarctic circles would be at 80 degrees north and 80 degrees south.

### What would happen if Earth’s tilt was less?

More tilt means more severe seasons—warmer summers and colder winters; less tilt means less severe seasons—cooler summers and milder winters. It’s the cool summers that are thought to allow snow and ice to last from year-to-year in high latitudes, eventually building up into massive ice sheets.

What if Earth’s tilt was 90 degrees?

But if Earth’s axis tilted to 90 degrees, extreme seasons would cause intense climate change on every continent. During the summer, the Northern Hemisphere would experience nearly 24 hours of sunlight for months, which could melt ice caps, raise sea levels, and flood coastal cities.

What if Earth’s tilt was 3 degrees?

Eclipses are caused by the relative positions of the Sun, Moon and Earth. We wouldn’t have much in the way of seasons if Earth’s axis of rotation were tilted only 3 degrees. The weather would get colder the farther you moved from the equator, but there would be very little seasonal change.

## What would Earth be like without a tilt?

If earth did not tilt and orbited in an upright position around the sun, there would be minor variations in temperatures and precipitation throughout each year as Earth moves slightly closer and farther away from the sun. Basically, we would not have any seasons.

What does the earth’s tilt cause?

The Short Answer: Earth’s tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun’s most direct rays. So, when the North Pole tilts toward the Sun, it’s summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it’s winter in the Northern Hemisphere.

Why is the Earth tilted at 23 degrees?

In the old model, Earth’s current axial tilt of 23.5 degrees resulted from the angle of the collision that formed the moon, and has stayed that way through time. Over billions of years, Earth’s rotation slowed from five hours to 24 as tidal energy was released.

### What if Earth was 10 feet closer to the sun?

You might have seen somewhere that if Earth were 10 feet closer to the sun, we would all burn up, 10 ft further and we’d freeze to death. On January, 2 a few seconds after 11:20 pm CST Earth was at perihelion a mere 91.4 million miles from the Sun, the closest point in its orbit.

What if the earth was not tilted at 23.5 degrees?

WHAT IF?: EARTH WAS NOT TILTED. At present Earth is tilted 23.5 degrees on its axis. In this case the plane of the Earth’s poles would always be perpendicular to the sun. The sun would always be just on the horizon 24 hours a day on every day at the poles.

Are all planets tilted?

It’s all in the tilt All the planets in our solar system have a tilted axis, which means all our planets have seasons – however, the seasons vary greatly in length, diversity and severity. “The greater the tilt in the axis, the more extreme the seasons are.”

## Which outer planet is the largest?

Basic facts

• Jupiter is the largest planet in our solar system.
• Saturn is about nine times Earth’s radius and is characterized by large rings; how they formed is unknown.