Galaxies Rorschach Tests

galaxy

Time Magazine’s Lightbox reports that the Hubble Space Telescope has found a bird-shaped galaxy in space.  One can describe galaxies in many ways, which suggests that galaxies as a whole can be considered a Rorschach test for viewers.

326 million light years from Earth, in the constellation Hydra, two galaxies are hovering near—or” near” at least in astronomical terms.  One looks like a bird with a sharp beak protecting its ovate soon-to-be progeny.  Astronomers have dubbed the bird the “Penguin.”

The bird is a spiral galaxy, designated as NGC 2936, the egg an elliptical galaxy, called NGC 2937.

It’s the egg, rather than the chicken, that predominates here.  The egg is exerting gravitational influence on the bird, stretching one side of the spiral into the shape of a beak.

Gravity is pulling many galaxies together.  A number of them are “interacting,” including NGC 2207 and IC 2163, 114 million light years away, the Mice galaxies, 300 million light years away, and the Antenna Galaxies, 45 million light years away, all of which are in  the midst of galactic collisions,

But more significant is what the the Hindustani Times recently reported.  The NASA Hubble Space Telescope has determined that the Andromeda Galaxy (M31), currently 2.5 million light-years away, is heading toward the Milky Way, due to the mutual pull of gravity between them and the influence of dark matter around them.  The crash will happen in about four billion years.   After that it will take two billion years more for the two galaxies to merge into a single elliptical galaxy.  The stars will be knocked about into different orbits around the newly created galactic center. Our solar system will end up much farther from the galactic core than it is today.

Two galaxies may collide with enough momentum that they pass through one another and keep on going, preserving their material and shape.  If there is not enough momentum, they may pass though one another several times before they finally merge.  If one galaxy is larger than the other, it’s the smaller galaxy that will be ripped apart.  This is described as “galactic cannibalism.”

Time Magazine’s Lightbox reports that the Hubble Space Telescope has found a bird-shaped galaxy in space.  One can describe galaxies in many ways, which suggests that galaxies as a whole can be considered a Rorschach test for viewers.

326 million light years from Earth, in the constellation Hydra, two galaxies are hovering near—or” near” at least in astronomical terms.  One looks like a bird with a sharp beak protecting its ovate soon-to-be progeny.  Astronomers have dubbed the bird the “Penguin.”

The bird is a spiral galaxy, designated as NGC 2936, the egg an elliptical galaxy, called NGC 2937.

It’s the egg, rather than the chicken, that predominates here.  The egg is exerting gravitational influence on the bird, stretching one side of the spiral into the shape of a beak.

Gravity is pulling many galaxies together.  A number of them are “interacting,” including NGC 2207 and IC 2163, 114 million light years away, the Mice galaxies, 300 million light years away, and the Antenna Galaxies, 45 million light years away, all of which are in  the midst of galactic collisions,

But more significant is what the the Hindustani Times recently reported.  The NASA Hubble Space Telescope has determined that the Andromeda Galaxy (M31), currently 2.5 million light-years away, is heading toward the Milky Way, due to the mutual pull of gravity between them and the influence of dark matter around them.  The crash will happen in about four billion years.   After that it will take two billion years more for the two galaxies to merge into a single elliptical galaxy.  The stars will be knocked about into different orbits around the newly created galactic center. Our solar system will end up much farther from the galactic core than it is today.

Two galaxies may collide with enough momentum that they pass through one another and keep on going, preserving their material and shape.  If there is not enough momentum, they may pass though one another several times before they finally merge.  If one galaxy is larger than the other, it’s the smaller galaxy that will be ripped apart.  This is described as “galactic cannibalism.”

The Milky Way may be gobbling up the Large and Small Magellanic Clouds, two irregularly shaped dwarf galaxies.  The Large Magellanic Cloud is about 163, 00 light years from Earth, the Small Magellanic Cloud about 200,000 light years away.  They are about 75,000 light-years apart from one another.  The evidence for the Milky Way’s cannibalism is the streams of hydrogen arcing from these dwarf galaxies into the Milky Way.

The Small Magellanic Cloud may be relatively small compared to the Milky Way, but it is not a wimp.  It is 7,000 light years across but contains several hundred billion stars.  The Milky Way is 120,000 light-years in diameter and contains about 400 billion stars.  In other words, the Small Magellanic Cloud has almost as many stars as the Milky Way at six percent the size.

Another phenomenon is called “galaxy harassment.”  This happens in dense clusters such as are found in the Virgo and Coma constellations.  Galaxies are moving at high relative speeds and frequently brushing into each other, basically because of lack of space, which can be compared to commuters on a crowded subway.

The terms “galactic cannibalism” and “galactic harassment,” as well as comparisons of galaxies to birds and characterize the human tendency to describe celestial objects in earthbound terms.  Little wonder then that our ancestors went around describing constellations as bears, scorpions, hunters and virgins.  We look at stellar congregations as if they were inkblots, and see into them what we will.  We do the Rorschach test.  It is a function of our capacity for abstract reasoning—theorizing, analyzing, evaluating, and solving problems.

The bird shape of NGC 2936 is not that unusual, if you consider the many shapes the galaxies can take. There are three (or four) categories for galaxies:  elliptical, spiral, lenticular and irregular (lenticular is not always included).  These are based upon the “bulge,” or distribution of stars at the center, and the disk, the distribution of stars, which can include spiral arms, such as the one in which our solar home base can be found.  Elliptical galaxies can look like eggs, for example, or footballs.  Spiral galaxies, like Andromeda, look like whirlpools.  Lenticular galaxies are shaped like lenses, or flying saucers.   Galaxies can look like sombreros, pinwheels, mice, antennas or spilled milk.   Scientific American talked to a group called Galaxy Zoo, which distributes computing projects for studying galaxies.  The name suggests the kinds of shapes that galaxies can take.

The last galactic category is irregular (i.e., miscellaneous).  Irregular galaxies have no symmetry.  These are the best examples of Rorschach tests for us.

By:  Tom Ukinski

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