What is the meaning of a 'light year'?
2009-11-05 4:08 pm
These scientists keep on talking about some galaxies being a couple of 'light years' away from our planet. I want to know the length of a 'LIGHT YEAR'!
回答 (14)
2009-11-05 4:12 pm
✔ 最佳答案
A light-year is a unit of distance. 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
2009-11-06 12:14 am
around 9461 billion kilometres, 5879 billion miles, or 0.3066 parsecs.
2009-11-06 7:53 pm
The distance that light travels in a vacuum in one year, approximately 9.46 trillion (9.46 Ã 1012) kilometers or 5.88 trillion (5.88 Ã 1012) miles.
2009-11-06 7:11 pm
light year nothing but a unit of distance .. its difficult to write and understand when we write more numerals so, they use the speed of light unit that is (3 X 10power 8 meter/second). they take one light year is equal to 3 X 10power 8 kilometers....
2009-11-06 4:33 pm
Imagine that u r travelling at the speed of light..... let ur travel begins JAN 1 of 2010 @ 1.00 AM from the sun.. then u wl reach our eath within 8mins. If u continue ur journey fr 4.1 years at the same speed then u reach our nearest star! It says the distance is very large that km or mi cant used to express them.
"Light year is the distance travelled by light in one year"
"Light year is the distance travelled by light in one year"
2009-11-06 1:29 pm
Unit of measurement of Ultra-solar system distances. A Light-year is the distance light travels in one year - at the rate of 186,000 miles per second, or about six trillion miles: 6 with 12 ciphers. Intra-solar system distances are measured in astronomical units. An astronomical Unit is the mean distance of the Earth from the Sun, about 92,930,000 miles, where it is found in April and October, at which time the Sun's light reaches the Earth in 499 seconds, or about 8 minutes. The inadequacy of this unit for ultra-solar system spaces can be seen by comparing the Pluto distance from the Earth, of 39½ A.U., light from which reaches the Earth in a little over five hours, with the distance of the next closest major body beyond Pluto, the star Alpha Centauri, light from which requires 4.3 years to traverse the intervening 25 trillion miles. Yet, if anyone on Alpha Centauri, despite its relative closeness, were to attempt to observe Pluto he would find it separated from the Sun by an arc of only 1", which means that Pluto and all the planets would be merged into the glare of the Sun, and give the appearance of an average star of the third or fourth magnitude.
2009-11-06 4:28 am
'LIGHT YEAR' is a unit for measuring distance. It is used for measuring astronomical distances between galaxies, whereas, miles is used to measure distance between 2 cities. A 'LIGHT YEAR' is the distance traveled by light in 1 year in vacuum. The YEAR in 'LIGHT YEAR' might be confusing, but 'LIGHT YEAR' has nothing to do with time.
2009-11-06 1:31 am
A light year is a unit od distance.its simply how far light can travel in ne year.
Using your basic speed,time,distance equation.
distance=speed*time.
speed of light is equal 3*10^8
and a year expressed in seconds is 365*24*60*60=31536000
therefor distance=3*10^8*31536000=9.461*10^15
=9,461,000,000,000,000m (accuracy is important!!)
Using your basic speed,time,distance equation.
distance=speed*time.
speed of light is equal 3*10^8
and a year expressed in seconds is 365*24*60*60=31536000
therefor distance=3*10^8*31536000=9.461*10^15
=9,461,000,000,000,000m (accuracy is important!!)
參考: my knowledge
2009-11-06 12:34 am
More than a couple!
A light year is a measure of DISTANCE not time.
Light travels about 5.8 TRILLION miles in one year.
The Andromeda Galaxy is 2.5 million light years away!
A light year is a measure of DISTANCE not time.
Light travels about 5.8 TRILLION miles in one year.
The Andromeda Galaxy is 2.5 million light years away!
2009-11-06 12:19 am
As everyone said, it's the distance light travels in a year. Since it takes light only about 5 and a half hours to reach Pluto, the distance it goes in a year is huge compared to our solar system.
But you didn't hear that galaxies are "a couple of light years away". Distances to other galaxies are measured in millions of light years. That is, it takes their light millions of years to get here.
Edited: I just realized that I never gave the actual distance. But other people did if you want the numbers.
But you didn't hear that galaxies are "a couple of light years away". Distances to other galaxies are measured in millions of light years. That is, it takes their light millions of years to get here.
Edited: I just realized that I never gave the actual distance. But other people did if you want the numbers.
2009-11-06 12:12 am
The distance the speed of light travels in one year. (the light wave travels).
Spock
Spock
2009-11-06 12:22 am
are so simple..
its a unit of measurement !!
its a unit of measurement !!
2009-11-06 12:14 am
for light to move 1 years legnth
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