A Story of Two Galaxies
08 September 2011


An image of a magnificent nearby pair of galaxies, known as The Eyes, due to their similarity to human eyes. The Eyes are located 100,000 light years apart, at an estimated distance of about 50 million light years from Earth. The image was acquired by the European Southern Observatory’s Very Large Telescope. It is the first publication of ESO’s Cosmic Gems programme, an ESO initiative for outreach.
Credit: ESO


The European Southern Observatory (ESO) recently published a wonderful image of two dazzling galaxies. Interestingly, these galaxies are known as The Eyes, as they resemble shining eyes. The image was obtained by ESO’s Very Large Telescope (VLT), one of the largest and most sophisticated observatories in the world. By astronomical standards, The Eyes are nearby galaxies, located approximately 50 million light-years away. They are about 100,000 light-years apart, a distance comparable to the width of our large Galaxy, the Milky Way .

Astronomers believe the larger of The Eyes galaxies, technically designated NGC 4438, was once a spiral galaxy, but has been deformed by collisions with other galaxies, in the last few hundred million years, a short period when compared to the age of the cosmos, estimated to be about 14 billion years.

The smaller galaxy of The Eyes, in the lower right of image, termed NGC 4435, is compact, and seems to be almost devoid of gas and dust, the raw material for star formation. Contrarily, NGC 4438 contains dark dust clouds, visible just below its core, young stars, and gas clouds.

One possible explanation of the deformation caused to NGC 4438 is a close encounter between The Eyes galaxies, when they came to within only about 16,000 light-years from each other, some 100 million years ago. NGC 4435 was even more influenced by Gravitational effects, which removed most of its gas and dust, and pulled away material from NGC 4438.

Another possibility is that a giant elliptical galaxy, known as Messier 86 (not shown in the image), further away from The Eyes, collided with NGC 4438, in the past. This is supported by recent observation of clouds of hydrogen connecting NGC 4438 and Messier 86.

Intriguingly, our Galaxy is expected to collide with its approaching giant neighbor, the Andromeda Galaxy, within three to four billion years.

Messier 86 and The Eyes belong to the Virgo Cluster, a large aggregation of galaxies, consisting of over 1,000 galaxies, held together by mutual gravitation. In such dense galactic groupings, galaxy collisions are fairly common.

References

ESO Press Release
Wikipedia


Aymen Mohamed Ibrahem
Senior Astronomy Specialist
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