Jupiter at Opposition?

Question

When Jupiter is at opposition would it be possible for the Earth to cast a small shadow onto it?

Answer 1

I'm sure there's an equation to determine the distance that Earth's shadow extends into space before reaching a vanishing point, but I'm sure that point is a very long way from Jupiter.

P.S.

There's a big difference between the transit of a planet across the face of the sun, which is nothing more than the planet *blocking* a bit of the sun's light, and that same planet throwing a *shadow* onto the surface of the planet from which the transit can be seen.

Answer 2

Yes, it is possible. Viewed from Jupiter, it could be seen as an Earth transit. It would be similar as a Mercury or Venus transit to us.

Answer 3

The Earth's umbral shadow extends for about 1.4 million km but Jupiter's distance at opposition this July is 622 million km, so the shadow falls well short and no shadow would be visible on Jupiter. However, as already answered, an observer on Jupiter could see the Earth silhouetted against the Sun at some Jupiter oppositions.

Answer 4

In theory yes. But you won't be able to spot it. The reason is earth have two types of shadows. One core shadow that is almost pitchdark. It extends like narrowing cone on the backside of the earth. The other is a semi intense shaddow that extends like a widening cone on the backside of the earth.

In order for the core shadow to be visible the object has to be within the tip of the cone. After that only the semi intense shadow is visible and it becomes  weaker and weaker the further away you get from earth.

In other words: You won't be able to see a dark spot on Jupiter because it's out of reach for the core shadow. The semi intense shadow will dim the light on the entire surface of Jupiter by a minute amount. But you'd probably need extremely sensitive instruments to detect it.

Try this: Draw a large circle (the Sun) and a small circle (earth) on a paper. Now draw two lines. One from the leftmost edge of the Sun thru the point where the line barely touches the leftmost edge of the earth and extend it somewhat beyond. Now do the same thing with the right side. Notice how these two lines forms a narrowing cone on the shaddow side of the earth. This is the core shaddow. The point where the lines crosses each other is where the core shadow turns into the semi intense type.

Now draw two more lines. One from the lefthand edge of the Sun to the righthand  edge of the earth and one from the right edge of the Sun to the left edge of the earth. So that the lines cross eachother on the sunny side of the earh. If you extend the lines beyond the earth you'll get the semi intense shadow. Notice how it's widening all the way from the earth. Therefore it gets fainter and fainter with the distance from earth.

It's a little complicated to describe. I hope you've got that last one. :-)

Answer 5

Make a diagram of similar triangles.

The bigger one with Sun's radius (432600 miles), the smaller Earth's (4000 miles). The other ratio is a distance 'd' where the Earth's  shadow ends and the bigger one of '1 AU + d'. When I solved for 'd', I got a value of  868,000 miles (5 thousandths of 1 AU) behind Earth. Far short to reach Jupiter at 4.2 AU at its closest.

Conclusion: Earth cannot cast a shadow on Jupiter (It can't on Mars even)