Astronomy Picture of the Day 6-18-02

NASA ^ | 6-18-02 | 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 June 18

IC 4406: A Seemingly Square Nebula
Credit: C. R. O'Dell (Vanderbilt U.) et al., Hubble Heritage Team, NASA

Explanation: How can a round star make a square nebula? This conundrum comes to light when studying planetary nebulae like IC 4406. Evidence indicates that IC 4406 is likely a hollow cylinder, with its square appearance the result of our vantage point in viewing the cylinder from the side. Were IC 4406 viewed from the top, it would likely look similar to the Ring Nebula. This representative-color picture is a composite made by combining images taken by the Hubble Space Telescope last June and this January. Hot gas flows out the ends of the cylinder, while filaments of dark dust and molecular gas lace the bounding walls. The star primarily responsible for this interstellar sculpture can be found in the planetary nebula's center. In a few million years, the only thing left visible in IC 4406 will be a fading white dwarf star.

[petuniasevan]

"Planetary" nebulae got that name from their often greenish appearance through a telescope - like a fuzzy Uranus or Neptune. You wouldn't confuse THIS nebula with a gas giant planet, though. From our vantage point, it appears to be square!

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[petuniasevan]

APOD PING!

[RightWhale]

Straight sides are unusual, whether a view of a cylinder or otherwise. What causes that?

[petuniasevan]

Not sure. Maybe nearby shock fronts (from supernovae) are a factor, or perhaps the star's spin rate influenced the direction of material ejected. Binary systems would produce weird nebulae too. Lots of planetary nebulae are strange-looking; astrophysicists are still studying the possible causes (that's scientist-speak for "we don't know").

[sleavelessinseattle]

The bubble guy in Seattle, who does parties for kids with soap solution and hoops and straws, can do square bubbles they're caused by the intersticial contact of precisely 6 bubbles and he inflates the contact point and when the little pocket gets big enough he takes a drag off a Highly PC Clove cigarette and blows smoke into the newly created pocket and sure enough...its SQUARE! more or less...If anyone came to FOLKLIFE...You'd KNOW these things!!! *beams...Next year! Memorial Day weekend...BE there or BE...

[Vets_Husband_and_Wife]

Our grandchildren are enjoying this as much as we do. I e-mail these to them. What fun!!! Thanks!!

Summer, I don't know if you know about this thread.. but it is just amazing. If not, ask petuniasevan to add you to her ping list. You will NOT be sorry!!!

FRegards!!

[summer]

Thanks! It IS fascinating!!! :)

[aomagrat]

!

[headsonpikes]

Say, were you the dreadlocked dude on the bongos at the bubble-blowing demo? ;^)

[sleavelessinseattle]

Jah Love mun...Feelin IRAE...Child o Zion Ave a day to remember don'tcha now, ear me say RASTA forever! no wasn't me...but I can channel their spirit when I'm not po'd about the latest liberal assault on our freedoms!!! LOL. Good one HOP!

[headsonpikes]

Yah, mon! You be the iriest bro on dis thread!

Haile Selassie be proud of you! Jamba!