How we measure the distance between two planets?

Answer 1

Measuring the light years

Answer 2

The distance between two planets is measured in light years. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More p recisely, one light-year is equal to 9,500,000,000,000 kilometers.

Why would you want such a big unit of distance? Well, on Earth, a kilometer may be just fine. It is a few hundred kilometers from New York City to Washington, DC; it is a few thousand kilometers from California to Maine. In the Universe, the kilometer is just too small to be useful. For example, the distance to the next nearest big galaxy, the Andromeda Galaxy, is 21 quintillion km. That's 21,000,000,000,000,000,000 km. This is a number so large that it becomes hard to write and hard to interpret. So astronomers use other units of distance.

In our solar system, we tend to describe distances in terms of the Astronomical Unit (AU). The AU is defined as the average distance between the Earth and the Sun. It is approximately 150 million km (93 million miles). Mercury can be said to be about 1/3 of an AU from the Sun and Pluto averages about 40 AU from the Sun. The AU, however, is not big enough of a unit when we start talking about distances to objects outside our solar system.

For distances to other parts of the Milky Way Galaxy (or even further), astronomers use units of the light-year or the parsec . The light-year we have already defined. The parsec is equal to 3.3 light-years. Using the light-year, we can say that :

- The Crab supernova remnant is about 4,000 light-years away.

- The Milky Way Galaxy is about 150,000 light-years across.

- The Andromeda Galaxy is 2.3 million light-years away.

Answer 3

The actual, exact length of the light-year depends on the length of the reference year used in the calculation, and there is no wide consensus on the reference to be used. The figures above are based on a reference year of exactly 365.25 days (each of exactly 24 hours). This is the value recommended by the IAU. However, other reference years are often used (eg. Yahoo's calculator uses a smaller value than the IAU), such that the light-year is not an appropriate unit to use when extremely high precision is required.

The IAU style guide [1] recommends the use of calendar years, specifically Julian (and not Gregorian) calendar years of 365.25 days or exactly 31,557,600 seconds. This gives the light-year an exact value of 9,460,730,472,580,800 meters, again about 9.461 Pm).

The light-year is often used to measure distances to stars. In astronomy, the preferred unit of measurement for such distances is the parsec, which is defined as the distance at which an object will generate one arcsecond of parallax when the observing object moved one astronomical unit perpendicular to the line of sight to the observer. This is equal to approximately 3.26 light years. The parsec is preferred because it can be more easily derived from, and compared with, observational data. However, outside scientific circles, the term light-year is more widely used.

Units related to the light year are the light-minute and light-second, the distance light travels in a vacuum in one minute and one second, respectively. Since the speed of light is defined as 299,792,458 metres per second, a light-second is exactly 299,792,458 m in length and a light-minute is exactly 17,987,547,480 m. In contrast to the light-year, the lengths of the light-minute and light-second are fixed with 100% precision.

Answer 4

You need to start by measuring the positions of the planets and calculating their orbits. Once you know those you can use Kepler's laws of planetary motion, but that'll only give you relative distances - you still need to know the distance of one planet from the sun. Earth's the obvious choice, and you can use transits of Venus to work out how far we are from the sun. Once you've got that, everything falls into place.

The planets are light minutes apart, but even the nearest stars, apart from the sun, are light years away.

Answer 5

Hi,

talking about light years is ok but the actual distance is now a days measured by lasers. Let it be sun,moon,any planet, height of mountains,depth of oceans and all.

LASERS are used now.

byeeee.

Answer 6

we measure the distance between two planets in 'light year'.

Answer 7

the time it takes for light to reach the other planet.Take the speed of light wich is about 300,000 km a second calculate the time it took for the light to reach the other planet.take the time multiplied by the speed and you will have a distance.

Answer 8

we measure it in the terms of light years

Answer 9

Trigonometry and Calculus and a lot of data collected by observation.

Answer 10

light years