[Pyrotex]

This is the caption assigned to the following picture:

NASA image from the Spitzer Space Telescope shows a fledgling solar system. European astronomers say they have located dozens of giant planets in three distant solar systems.

My question is: Is this a real picture of a nascent planetary system? Or is it an artist's rendering? It almost looks too good to be true.

Hmmm...

[freeztar]

It's an artist's conception.

Image ssc2007-14d

[Pyrotex]

Thanks. At the Exoplanetary Convention, being held as we speak in Nantes, France, this picture was posted as an "image taken by the Spitzer Observatory".

Even if you assume the diameter of the dark ring to be about 10X the diameter of Neptune's orbit (which is reasonable), that would represent an incredible resolution, even for a space telescope.

BTW, I propose that we use the diameter of Neptune's orbit as a Unit of Distance. I call it, the Nepton. The reason for this choice is that if you take Neptune's major axis (60.1 AU), that is almost exactly 1/1,000 of a LightYear. An AU is an Astronomical Unit, the distance from Earth to Sun, or the radius of the Earth's orbit.

Actually, 0.001 LY would be 62.9 AU. Close enough. We can define the Nepton as one milli-LY. Waddaya think?

The AU is useful for planetary distances, and the LY is useful for stellar distances, but we need a measure somewhere in between. The Nepton is 63 AU, and 1,000 Neptons make a LY. Very useful for evaluating small nebula and dust clouds.

[freeztar]

That sounds like a good idea to me, Pyro.

I'm not too fond of the name though, as it sounds more like a particle than a measurement of distance.

As for space pictures, I suppose if we knew the distance to the object and the angular resolution of the scope, we could determine the amount of detail that could be obtained and judge supposed "photos" based on this. I suppose this is what you did (in an informal manner perhaps) for this "photo".

[modest]

Originally Posted by Pyrotex

Actually, 0.001 LY would be 62.9 AU. Close enough. We can define the Nepton as one milli-LY. Waddaya think?

I like this idea. I half remember trying to use milliparsecs or centiparsecs before to describe something between the usefulness of au and lightyears. The diameter of Neptune's orbit would have been a better approach.

Now, how does one go about introducing a new unit of distance

-modest