Astronomy Picture of the Day 4-11-02

NASA ^ | 4-11-02 | 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 April 11

Antennae Galaxies in Near-Infrared
Credit: Bernhard Brandl and the WIRC team (Cornell), Palomar Observatory

Explanation: What happens when galaxies collide? One of the best studied examples of the jumble of star clusters, gas, and dust clouds produced by such a cosmic train wreck is the interacting galaxy pair NGC 4038 / NGC 4039, the Antennae Galaxies, only sixty million light-years away. In visible light images, long, luminous tendrils of material seem to reach out from the galactic wreckage, lending the entwined pair an insect-like appearance. But this penetrating view from the new Wide-field InfraRed Camera (WIRC) attached to the Palomar Observatory's 200 inch Hale telescope shows, in false-color, details of some otherwise hidden features. The large central nuclei of the two original galaxies dominate the near-infrared scene speckled with other bright sources which are themselves giant, newly formed star clusters. Remarkably the northern (topmost) nucleus, obscured in optical images, is also revealed here to have a barred, mini-spiral structure reminiscent of many "single" spiral galaxies.

[petuniasevan]

The amazing thing is that there were probably NO stellar collisions during this encounter;
only the gravitational influences distorted these galaxies.

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[petuniasevan]

APOD PING!

[freeeee]

Please add me to the APOD ping list. Thanks!

[aomagrat]

Amazing!

[glock rocks]

i'm amused by the train wreck analogy.

well no, its more like two galaxies colliding! great pic. thanks.

[headsonpikes]

APOD ping list request!

Thanks.

[RightWhale]

Suppose the sun were to be flung out of the Milky Way by such a collision, say by an interaction with M31, would the change in the sun's neighborhood change conditions in the sun itself and on earth besides having far fewer visible stars afterwards and more stars during?

During the collision would planets fare less well than stars due to the passage of gravitational fields and a galaxy full of debris through the vicinity of the sun?

The heliopause is quite a distance out, but nowhere near halfway to the next star. Would the heliopause move farther out than its present radius of about 100 AU?

[farmfriend]

bttt

[glock rocks]

excellent question. thanks.

in that instance, would not time (and the fabric of local space-time
due to the severe gravity fluctuations) change as well?

now, would we notice this change? (i don't think so.)
what other changes would we not notice, even though
to an outside observer major changes would be evident?

put yourself into einstein's inertial reference frame elevator
and ponder whole galaxies colliding. lotsa variables.

in the relative mean time, i think i'll go ponder
a cold miller and change my truck battery.

[altair]

The amazing thing is that there were probably NO stellar collisions during this encounter; only the gravitational influence

(Thanks as always for the APOD ping). It's not so surprising when you consider the difference between the average distance between galaxies and the average distance between stars. The average distance between galaxies is only something like 10 times the size of the galaxies themselves. That's not very much. Our own galaxy is on a collision course with the Andromeda galaxy and the sun isn't likely to hit anything, but I think that's far enough in the future it will already have gone nova and turned into a white dwarf.

[Vigilantcitizen]

Due to the marathon work sessions I have been pulling in the last 10 days, I have been missing my daily APOD fix.

Keep 'em coming...