Question

Hello everyone,
Good morning!



Question for today:
The distance from the earth to the moon can be measured very accurately by timing how long it takes a special beam of light to reach the moon and reflect back. Find out the name of the beam of light that is used for this purpose. Why can't an ordinary beam of light be used?

Rules:
Please answer correctly, no matter the time you take. Don't post irrelevant answers, if you do, they will be reported and you will lose your points.

Good luck! ​

Answer 1

Answer:

Hello everyone,

Good morning!

Question for today:

The distance from the earth to the moon can be measured very accurately by timing how long it takes a special beam of light to reach the moon and reflect back. Find out the name of the beam of light that is used for this purpose. Why can't an ordinary beam of light be used?

Rules:

Please answer correctly, no matter the time you take. Don't post irrelevant answers, if you do, they will be reported and you will lose your points.

Good luck!

Answer 2

● Light speed is about 300.000 km/s

the average distance from the center of the Earth to the center of the Moon is 384.403 km.

The time to reach the moon and come back is the time that light need to take

= 384.403 km × 2

=768.806 km

so, the time it takes for a beam of light to reach the moon and back

(768.806 km) / (300.000km/s) = 2.56s

● The beam of light to reach the moon and reflect back is call - Moonlight

● the faint brightness of the rest of the moon, the part not brightly lit as a sliver — is a result of what scientists call "earthshine,"

● if ordinary beam of light be use, it'd be spread out over a large fraction of the surface when it got there. The atmosphere would distort the beam a bit, and absorb some of it. so we can't use an ordinary beam.