Extremely Cool Astronomy News

[Pax]

Originally posted by geoschmo:
That makes sense slick, but it still looks wrong to me. Shouldn't the planets be side to side instead of top to bottom? I thought maybe the image was sideways, but then the shadow on earth would be wrong and the cloud bands on jupiter too.

Geoschmo

Contrary to popular misconception, not EVERY planet's orbit lies in the exact same plane; there are angular differences between each (and it tends to follow a pattern, IIRC ... the inner planets further and further off of the plane of, say, Neptune's orbit).

As to their placement, I would suspect the following:

code:

---

.    J

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.                              S

.

.                E

.

.          ^

.          |

.          |

.          |

.          M

---

(The arrow denotes the direction of the camera; the periods are only to maintain vertical spacing)

Mainly due to the differences in what's "lit up" and what'snot; Earth is in almost peerfect profile, turned JUST a little away form the camera -- so the Sun should be not-quite directly to the right of the Earth, in terms of direction.

However, Jupiter is almost face-on to us; that means the angle from the camera to the sun, relative to Jupiter, mustn't be all THAT large.



[ May 23, 2003, 19:44: Message edited by: Pax ]

[Aloofi]

My, do we live in that little blue sphere?

.

[geoschmo]

Ok, if I sound skeptical, I am not at all. I have no doubt this picture is legit, I am just not thinking about it correctly to understand what I am seeing. I had forgotten the planets were in different planes, so that explains the over/under. But I still am not seeing it totally right.

From your descriptions, and from the angle of the sunlight on the planets I made this graphic. It's not to scale of course, but does it correctly represent the relationship of the planets in the photo?



If it does, shouldn't Jupiter be way smaller than it is in the picture? At this angle and magnification, Jupiter should appear farther away from the camera then it does from us here on earth. And yet Jupiter from earth is just a small colored dot.

Still

Geoschmo

[PvK]

Yes, the planets would be a lot smaller than your dots.

You have it right. See the map that is essentially the same as yours at:

this web page

It's dots are also way off scale, as is necessary for them to be visible.

Yes, Jupiter is much farther away than the Earth, but they are both very far away, so the absolute difference in size from parallax between the two isn't that great, because the effect of parallax isn't directly proportional to distance. Also, Jupiter is a lot bigger than the Earth.

PvK

[geoschmo]

Hehe, I finally got the original site to load (very slow) and it's got more information. It has agraph of the planet positions and my diagram is almost exactly right. (Yay me. ) But I still can't figure the apparent (to me anyway) size difference. The site says the images were taken seperatly and mosaized together. I wonder if the two planetary images are at different magnifications? It doesn't say they are, but that would explain it.

Geoschmo

[geoschmo]

Originally posted by PvK:
Yes, Jupiter is much farther away than the Earth, but they are both very far away, so the absolute difference in size from parallax between the two isn't that great, because the effect of parallax isn't directly proportional to distance. Also, Jupiter is a lot bigger than the Earth.

PvK

Ah, I think I understand. Since the planets are both very far away, they begin to appear to be closer in size because of the parallax. Then magnify the total image so the planets are more distinguishable and earth's size is way out of proportion to Jupiter. That makes sense.

So if instead of magnifying the image, we hopped in a ship and flew towards earth to the point where it's the same size as in the magnified image, Jupiter would still be a tiny dot no larger then what we see in our sky.

Thanks, that does make sense now.

Geoschmo

[Slick]

Yes, the diagram is as how I think the pic was taken.

The best way I can explain it is that the pic was obviously taken with some telescopic lens and (after a bit of research) the diameter of Jupiter is 11.21 times Earth's diameter. So, even though it is farther away, the planets appear roughly similar in size. If they were at the same radius from the camera, Jupiter would take up much more of the picture.

Slick.

[ May 23, 2003, 20:40: Message edited by: Slick ]

[Slick]

Holy Smokes! When I hit reply for the previous post, there were no Posts after the one with Geo's pic. And it certainly didn't take me long to type it. All the in-between Posts came in at about the same minute.

Slick.

[Aloofi]

Wait a minute, they say that the picture is colored!!!
What the heck that means? that it isn't real?

[minipol]

It's not because they "retouch" a picture that it's not real. It means they make the colours clearer so you can see the colours better. No conspiracy here