Astronomy Picture of the Day -- The Einstein Cross Gravitational Lens

NASA ^ | January 02, 2012 | (see photo credit)

[SunkenCiv]

Explanation: Most galaxies have a single nucleus -- does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image. The central cloverleaf is rather light emitted from a background quasar. The gravitational field of the visible foreground galaxy breaks light from this distant quasar into four distinct images. The quasar must be properly aligned behind the center of a massive galaxy for a mirage like this to be evident. The general effect is known as gravitational lensing, and this specific case is known as the Einstein Cross. Stranger still, the images of the Einstein Cross vary in relative brightness, enhanced occasionally by the additional gravitational microlensing effect of specific stars in the foreground galaxy.

[SunkenCiv]

[Credit & Copyright: J. Rhoads (Arizona State U.) et al., WIYN, AURA, NOAO, NSF]

[left that other site]

LIKE!

Happy New year, FRiend!

Thank you for your faithfulness to this Thread.

[onyx]

Looks very lonely by itself out there.
Interesting!

[SunkenCiv]

Happy Perihelion Day! Today the Earth was closer to the Sun than it will be on any other day of its orbit. Northern hemisphere winters are just a scoche less cold, and northern hemisphere summers just a scoche less warm, than those of the southern hemisphere, as a consequence of this slight (.02 eccentricity) irregularity of this elliptical orbit we're all on.

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[SunkenCiv]

Thanks LTOS for the kind remarks!

[martin_fierro]

Nonsense. That's a refection in a window.

[colorado tanker]

Today is also Fruitcake Toss Day. And a happy one to you, Civ!

[TheOldLady]

Happy Perihelion Day to you too, handsome!

Einstein Cross, huh. Learn something new every day!

Thank you, my friend.

[SunkenCiv]

Yeah, it’s little known, but Einstein worked his way through school as a boxer, and originated that “Einstein Cross” move.

[TheOldLady]

*Snort* [giggles]

Really? No kidding! Right cross or left cross?

[gonzo]

KEWL!! Thanks, sunkenCiv! ....................................................... FRegards

[gonzo]

KEWL!! Thanks, SunkenCiv! ....................................................... FRegards