Astronomy Picture of the Day 5-12-02

NASA ^ | 5-12-02 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2002 May 12

At the Edge of the Helix Nebula
Credit: R. O'Dell and K. Handron (Rice University), NASA

Explanation: While exploring the inner edge of the Helix Nebula with the Hubble Space Telescope's Wide Field Planetary Camera 2, astronomers were able to produce this striking image - rich in details of an exotic environment. This planetary nebula, created near the final phase of a sun-like star's life, is composed of tenuous shells of gas ejected by the hot central star. The atoms of gas, stripped of electrons by ultraviolet radiation from the central star, radiate light at characteristic energies allowing specific chemical elements to be identified. In this image, emission from nitrogen is represented as red, hydrogen emission as green, and oxygen as blue. The inner edge of the Helix Nebula, also known as NGC 7293, is in the direction toward the central star, which is toward the bottom left. Clearly visible near the inner edge are finger shaped cometary knots.

[petuniasevan]

I know that some naysayer is going to show up and tell us all how this image is "misleading" because it is the result of a stream of electronic data. DUUHHH! Every image from every remote probe, orbiting telescope, and spacecraft is sent this way!

Sure, this image seems unreal. Oh, it's real, all right. It just doesn't show what human eyes would see. Photos like this are processed to emphasize certain details, and for a good reason. The astronomers and astrophysicists are studying this nebula to learn more about the dying star within, not hawking this as art (though it unwittingly is).

By the way, the cometary knots you see are huge. Each one is the diameter of our solar system, and the "tail" on each measures about 100 billion miles. They seem to originate from the interaction of fast-moving shock waves interacting with slower-moving earlier mass ejections.

[petuniasevan]

Here's a wide shot of the entire Helix Nebula for proportion.

Get on the APOD PING list!

[petuniasevan]

APOD PING!

[petuniasevan]

Someone re-oriented the image or boo-booed.

which is toward the bottom left should read top right.

[RightWhale]

They say the cometary knots may collapse to form Pluto-like objects, and that such objects would be common in the galaxy. It could be that the Kuiper Belt region of solar system space beyond Pluto is populated with such objects.

[petuniasevan]

This might be a vindication of the theory of dark matter in the form of MACHOs (MAssive Compact Halo Objects).

[farmfriend]

There was another thread that was a new theory on the whole dark matter thing. Looking.

[farmfriend]

Fast Particles Inflated Universe

[petuniasevan]

Remember how I mentioned that the "tails" on those cometary knots are around 100 billion miles long? To put it in proportion, that's over 10 times the diameter of planet Pluto's orbit, but still only 1/60th of a light-year, or about a light-week. Thus, if there are changes in the lighting of a certain knot, it takes about a week to become apparent.

[sleavelessinseattle]

The false color doesn't bother me, Its a graph of matter distribution coupled with UV light saturation...Its BEAUTIFUL!!!!Thanks for your efforts, P7!

[Helix]

Helical BUMP!