Space Shuttle Eclipses Sun May 13 (Reduces AGW Heat Load for 0.8 Seconds)

Solar Cycle 24 ^ | May 14 2009 | NASA

[Robert A Cook PE]

Impressive, very beautiful photo's on this solar cycle 24 thread.

Short-lived man-made sunspot.

[Robert A Cook PE]

Then again, would it be cheaper to put up a whole lot of shuttles and umbrellas to shade more of the sun than to put up with a (false) cap-and-tax bill?

[Robert A Cook PE]

Impressive.

[Buck W.]

Louis Caldera is at it again...

[MyTwoCopperCoins]

I’ve aways wondered... does the Sun really look that big just outside the Earth’s atmosphere?

[freedumb2003]

Very cool...

[patton]

Neat!

[steelyourfaith]

Another brilliant, Nobel-Prize-worthy-idea to save the globe from Anthropogenic Global Warming ™Anthropogenic Climate Change ™ . As such this would seem to have Steven Chu's name written all over it.

Thanx !

 

Beam me to Planet Gore !

[ciwwaf]

No. That’s from magnification of a telescope. Takes getting used too. If you want to see more photographs like that look up mercury photos. The sun looks huge and the planet very close to it. But in reality the sun looks only slight brighter from mercury.

[robomatik]

as a fan of the space shuttle since it made it’s debut in the bond film, “moonraker,” i will miss it when it’s gone!

[Lonesome in Massachussets]

That doesn’t answer the important policy question: Who gets to set the global thermostat?

If the Chinese or Indians want it cooler will they send up their own orbiting debris? If the Norwegians want it warmer will they sue in the International Court of Justice?

[Atlas Sneezed]

But in reality the sun looks only slight brighter from mercury.

---

Actually, like all extended objects, the surface of the sun looks no brighter from Mercury than from earth. It’s just that it covers a larger angle of the sky from Mercury, so more illumination falls onto a given area of Mercury.

[Talisker]

Actually, like all extended objects, the surface of the sun looks no brighter from Mercury than from earth. It’s just that it covers a larger angle of the sky from Mercury, so more illumination falls onto a given area of Mercury.

I'm not following your logic. On an 8x10 piece of paper, the reflection would be brighter on Mercury because it is closer than the Earth, because there is less loss of energy through distance. While if you took the paper away, the larger angle of the sky would not change the total amount of transmitted energy, but you'd still be closer on Mercury, so it still should be brighter overall because of the larger amount of received energy.

[A.A. Cunningham]

It looks that big when you look at it through one of these.

Thierry Legault in his back garden in Paris. The astrophotographer has captured impressive pictures of the sun

Solar powered: Amateur astronomer snaps space shuttle and telescope speeding across the sun

[Professional Engineer]

Then again, would it be cheaper to put up a whole lot of shuttles and umbrellas to shade more of the sun than to put up with a (false) cap-and-tax bill?

Surely you jest. That would further enrich already wealthy North American white males.

BTW, Awesome photo.

[alexander_busek]

I'm not following your logic. On an 8x10 piece of paper, the reflection would be brighter on Mercury because it is closer than the Earth, because there is less loss of energy through distance. While if you took the paper away, the larger angle of the sky would not change the total amount of transmitted energy, but you'd still be closer on Mercury, so it still should be brighter overall because of the larger amount of received energy.

What "reflection" are you talking about?

What "piece of paper" are you talking about?

Mercury is roughly 0.4 A.U. (Astronomical Units) from the Sun (though its orbit is more eccentric than that of any other planet - since Pluto is no longer considered to be a full-fledged planet - so that's the mean distance). The Earth is 1 A.U. from the Sun. The angular extent of the Sun as seen from Mercury is thus one divided by 0.4, i.e., 2.5. So while the Sun has an angular diameter of 0.5 degrees when viewed from the Earth, it has an angular diameter of 1.25 degrees (i.e., two and a half times 0.5 degrees) when viewed from Mercury.

That means that, on Mercury, the Sun appears two and a half times wider and two and a half times higher than when seen from the Earth. Hence, the angular area of the Sun (as seen from Mercury) is 2.5 X 2.5 = 6.25 times what it is as seen from the Earth.

Every square meter of Mercury's surface thus receives approx. 6.25 times as much sunlight as the same area on Earth.

On Mercury, the Sun's surface does not appear intrinsically brighter than for an observer on the Earth - but there is 6.25 times as much apparent surface area to see.

OK, now I understand your reference to a sheet of paper! You were making an example.

A sheet of paper (or any other reflective object) held by an observer on Mercury would be illuminated by 6.25 times as much sunlight as a comparable piece of paper held by an observer on the Earth. The paper would, indeed, be brighter.

By the same token, the planet Mercury as seen in Earth's night sky appears 6.25 times as bright as it would were it at a distance of 1 A.U. from the Sun (but still the same distance from the Earth).

((In actual fact, Mercury - and our Moon - both have very low intrinsic albedos; they are roughly as dark as asphalt.))

Regards,

[mikrofon]

Timing is everything...

[NonValueAdded]

No, very hot.

[freedumb2003]

Hey, there are rules against posting telescope pron!!!

:)

[Talisker]

Hence, the angular area of the Sun (as seen from Mercury) is 2.5 X 2.5 = 6.25 times what it is as seen from the Earth.

Thanks for the calculation. I couldn't get my head around the distance<=>solar-intensity relationship except in a general way.

And yeah, I was making an example to try to visualize a measurable relationship.

[Robert A Cook PE]

Telescope pron?

Shirley that ain’t no shrimpy ‘scope!