What will happen -- Mirrors on the Moon to illunimate the Earth....

[Saleh0003]

if we fix huge amount of mirrors on surfface of moon...can we obtain light on Earth during night ?

 

[tfr000]

Most of the light would not be reflected toward the Earth.

 

[OmCheeto]

if we fix huge amount of mirrors on surfface of moon...can we obtain light on Earth during night ?

Yes.
But we already obtain light on Earth at night from the moon, without mirrors, so I'm wondering why you think that we might want more light at night.

 

[tfr000]

A better idea would be to simply paint the Moon white. As is, it's charcoal grey, although it doesn't look like it in the night sky.

 

[rootone]

Is the question to do with installing solar reflectors on the Moon so that these could provide an additional energy source for Earth?
If so then yes it's possible from an engineering point of view, but pointless because very little of the light already reaching the Earth from the Sun is utilized directly as an energy source.

 

[Saleh0003]

Yes.
But we already obtain light on Earth at night from the moon, without mirrors, so I'm wondering why you think that we might want more light at night.

coz...surface of moon is rough so it is not reflecting properly sunlight but with mirrors, we can obtain it at night which may plays an important role in food chain

 

[SteamKing]

if we fix huge amount of mirrors on surfface of moon...can we obtain light on Earth during night ?

The position of the moon with respect to the Earth is not fixed. At some times during the month, the moon is actually located on the opposite side of the Earth from the night side. What will you do with your mirrors then?

 

[Saleh0003]

The position of the moon with respect to the Earth is not fixed. At some times during the month, the moon is actually located on the opposite side of the Earth from the night side. What will you do with your mirrors then?
you are right but this is just supposition that if it happens can we obtain same light of sun as we obtain during day?

 

[OmCheeto]

coz...surface of moon is rough so it is not reflecting properly sunlight but with mirrors, we can obtain it at night which may plays an important role in food chain

I suppose it would work, theoretically.
We discussed telescopes on the Moon, which is basically your idea on a smaller scale.

The position of the moon with respect to the Earth is not fixed. At some times during the month, the moon is actually located on the opposite side of the Earth from the night side. What will you do with your mirrors then?

The biggest "selfie" mirror ever?

 

[Saleh0003]

I suppose it would work, theoretically.
We discussed telescopes on the Moon, which is basically your idea on a smaller scale.The biggest "selfie" mirror ever?

yeah! As people have much craze of selfies these days ...so it will work in better way :)

 

[SteamKing]

you are right but this is just supposition that if it happens can we obtain same light of sun as we obtain during day?

Goodness! Why would you want to abolish nighttime? That would screw things up beyond all recognition...

 

[Saleh0003]

Goodness! Why would you want to abolish nighttime? That would screw things up beyond all recognition...

lot of sins take place at night...Probably we achieve peace on Earth :)

 

[A.T.]

Goodness! Why would you want to abolish nighttime? That would screw things up beyond all recognition...

Or as Black Sabbath put it: The moon is just the sun at night

 

[OmCheeto]

Goodness! Why would you want to abolish nighttime? That would screw things up beyond all recognition...

Yes, many nocturnal animals might go extinct.
That would be a shame.

 

[SteamKing]

lot of sins take place at night...Probably we achieve peace on Earth :)

Sin is a 24 hour a day business. I think that having no day/night would make things worse, not better.

 

[volvot]

Yes, many nocturnal animals might go extinct.
That would be a shame.

I agree with you, day and night is a natural phenomena, if we broken up this, Life on Earth is to be broken，that will be horrible.

 

[Merlin3189]

If we could significantly increase the amount of energy we receive from the sun, wouldn't that increase "global warming"?

 

[rootone]

It wouldn't increase the greenhouse gas effect as such, but still the extra heat would accumulate, so that would add extra heat on top of existing global warming.
It would not only affect long term climate trends but would completely change local weather patterns, I would expect this resulting in the complete loss of polar ice in a short timescale.

 

[derek10]

Goodbye circadian rhythms

 

[nasu]

lot of sins take place at night...Probably we achieve peace on Earth :)

Sins? Like watching adult TV? Or even turning on the electric lights according to some religious varieties.

 

[OmCheeto]

If we could significantly increase the amount of energy we receive from the sun, wouldn't that increase "global warming"?

Lots of problems ran through my mind. This was one of them.
This "mirrors on the moon" is similar to someone's "energy beam from space" idea.
I believe it was @nsaspook that posted something about the current power level of moonlight being 400,000 times less than from the sun. (Very interesting experiment!) Increasing the albedo alone, by painting the moon white, would yield light that is about 40,000 times less than from the sun. Has anyone successfully grown tomatoes in the shade?
So using mirrors would be the only logical solution.
But they would have to continuously adjustable, as the sun-moon-earth angle would have the reflected sunlight just beaming back out into space most of the time.
But as I mentioned in the "energy beam from space" idea thread, if anything goes wrong, and the beam should somehow become too focused, we end up with disaster.

​

 

[DaveC426913]

The engineering solution to lighting the nightside of the Earth is not mirrors on the Moon but mirrors in orbit. There is quite a bit of literature about it.
It's much more feasible:
- much closer
- don't need to climb into and out of a moon's gravity well to visit/service
- in micro-g so structure can be gossamer-light
- reflection can subtend an arbitrarily large angle of the sky
- can be moved around as needed
- etc.

The question is: would we want to, and should we?

 

[mrspeedybob]

At a fundamental level, the energy from the sun is useful because it is low in entropy, it only comes from one direction at a time. If we had sunlight from a variety of directions then the entropy of that energy would be higher and it would be less useful for doing work.

A heat engine will only operate if you have a heat sink. If you have heat all around the heat engine it cannot operate, even though it has more energy available, the energy cannot be converted into work. Same idea with the sun. Everything on Earth is essentially a heat engine of one sort or another with the direction of the sun being the heat source and every other direction as the heat sink. If we mirrored the moon we would get more heat, but less useful energy then we have now.

 

[Drakkith]

If we mirrored the moon we would get more heat, but less useful energy then we have now.

I don't think this is true. It isn't simply a matter of the Earth being 'surrounded' by a heat source. It's much more complicated than that.

 

[nsaspook]

I believe it was @nsaspook that posted something about the current power level of moonlight being 400,000 times less than from the sun. (Very interesting experiment!) Increasing the albedo alone, by painting the moon white, would yield light that is about 40,000 times less than from the sun.

I'm running some baseline tests (at nanowatt resolution) this week with the new gear on the Raspberry PI with about 240 Watts of panels as the moon gets closer to full every night and using the Portland moon charts to give me the percentage of full and distance. I hope to post some charts on the moon power thread if the weather holds. The forecast so far looks good for this time of year if we don't get junk that night.

http://archive.kgw.com/weather/images/core/7day.jpeg

 

[rootone]

The brightest white paints are based on Titanium compounds. so that project of painting the Moon white would need to begin with Titanium mining and processing.

 

[OmCheeto]

The engineering solution to lighting the nightside of the Earth is not mirrors on the Moon but mirrors in orbit. There is quite a bit of literature about it.
It's much more feasible:
- much closer
- don't need to climb into and out of a moon's gravity well to visit/service
- in micro-g so structure can be gossamer-light
- reflection can subtend an arbitrarily large angle of the sky
- can be moved around as needed
- etc.

The question is: would we want to, and should we?

Saleh0003, the OP, mentioned in post #6 that he wanted it for food production.
Interesting idea. And we already have data on the effects of extended sunlight hours on crops

How Midnight Sun Affects The Environment
...
Parts of Alaska such as the Tanana Valley between Fairbanks and Delta and the Matanuska Valley near Anchorage are famous for their production of gigantic vegetables. Among the largest vegetables have been a 138 pound cabbage from Wasilla, and 18.9-pound carrot from Palmer, and a 1,287 pound pumpkin from Nikiski on the Kenai Peninsula.
...

I think it would take me a week to eat a 20 lb carrot!

Should we do it? IMHO, no. At least, not yet.
And since it's purpose is food production, I think we can rule out painting the moon.

 

[Hasratbrar]

Mirrors will not work always as moon's position with respect to the Earth is not fixed
So what are you going to do with those mirrors then; p

 

[DaveC426913]

Mirrors will not work always as moon's position with respect to the Earth is not fixed
So what are you going to do with those mirrors then; p

Same thing we do with mirror arrays now. Make em tiltable.Anyway, it's still a far better option to put em in Earth orbit. Their location above the night side as well as their orientation to the Sun is built right in.

 

[Hasratbrar]

Same thing we do with mirror arrays now. Make em tiltable.Anyway, it's still a far better option to put em in Earth orbit. Their location above the night side as well as their orientation to the Sun is built right in.

Yes this option may work better than putting mirrors on moon from engineering point of view

 

[mrspeedybob]

Should we do it? IMHO, no. At least, not yet.
And since it's purpose is food production, I think we can rule out painting the moon.

Re-directing enough light for enough time for food production seems a bit impractical. Especially since so much un-used land is available to increase food production at a fraction of the cost. What might be practical though would be a large scale emergency lighting system. You could rotate the mirrors and illuminate remote areas for night time disaster relief, search and rescue, or military operations much more quickly then transporting and setting up large earth-bound generator / flood light systems.

 

[lightarrow]

if we fix huge amount of mirrors on surfface of moon...can we obtain light on Earth during night ?

In case, it could theorically be useful to concentrate those mirrors' light on collectors on Earth to get electric energy. Clearly those mirrors should be perfectly adjustable via Earth control. Not possible with actual technology, anyway.

--
lightarrow

 

[Neon]

If we did build mirrors on the moon, it must be rotated as the moon is not only at different points of view but also like like up and down from the earth.​

And that is why we don't get the beautiful lunar eclipse every month.:(

 

[lightarrow]

If we did build mirrors on the moon, it must be rotated as the moon is not only at different points of view but also like like up and down from the earth.​

And that is why we don't get the beautiful lunar eclipse every month.:(

Certainly I didn't mean to rotate the Moon too :-) We should be satisfied to have light for half of the time (= it's better than nothing).
But probably it would cost less (for every kW of energy collected) to put many mirrors in orbit around Earth, I really don't know this.

--
lightarrow

 

[OmCheeto]

...
Anyway, it's still a far better option to put em in Earth orbit. Their location above the night side as well as their orientation to the Sun is built right in.

I just learned this morning, that the Russians actually did this.
For a few hours anyways.

The Man Who Turned Night Into Day
WRITTEN BY BRIAN MERCHANT
January 20, 2016 // 10:00 AM EST
...
After years of development, in 1992, Syromyatnikov and his team launched the 88-pound Znamya-2 into space aboard a vessel called Progress M15, bound for the Mir space station as a secondary payload.
...
As planned, on February 4, Znamya left Mir. When it found its orbit a safe distance away, the mirror successfully deployed. And, sure enough, it sent a five kilometer-wide beam of light back down to Earth. The beam swept through Europe, moving from the south of France to western Russia at a reported speed of eight kilometers per second. “Several” turned out to be an overstatement—its luminosity was equivalent to a single full moon’s. Unfortunately, excessive cloud cover prevented the effect from being seen much on land; as the BBC reported, some Europeans reported noticing a flash of light as it glanced by, but that was about it.

Still, the theory had proved correct, and the design was sound. Znamya was de-orbited after a few hours and burned up in the atmosphere above Canada upon reentry.
...