Galaxies lead a very graceful existence on cosmic timescales. Over millions of years, they will engage in elaborate dances that produce a few of nature’s most exquisite grand designs. Few are as captivating because the galactic duo generally known as NGC 5394/5, sometimes nicknamed the Heron Galaxy. This picture, obtained by the Gemini Observatory of NSF’s National Optical-Infrared Astronomy Research Laboratory, captures a snapshot of this compelling interacting pair.
The existence of the universe depends upon interactions—from the tiniest subatomic particles to the biggest clusters of galaxies. At galactic scales, interactions can take millions of years to unfold, a process seen on this picture of two galaxies launched today by the Gemini Observatory. The new picture captures the slow and intimate dance of a pair of galaxies, some 160 million light-years distant, and reveals the glint of subsequent star formation fueled by the pair’s interactions.
The 2 galaxies, astronomers have concluded, have already collided at the very least once. Nevertheless, galactic collisions is usually a lengthy process of successive gravitational encounters, which, over time, can morph the galaxies into exotic, unrecognizable varieties. These galaxies, as in all galactic collisions, are engaged in a ghostly dance because the distances between the stars in every galaxy preclude precise stellar collisions, and all shapes are deformed only by every galaxy’s gravity.
NGC 5394 and NGC 5395, is also collectively called Arp 84 or the Heron Galaxy, are the interacting spiral galaxies 160 million light-years from Earth within the constellation of Canes Venatici. The bigger galaxy, NGC 5395, is 140,000 light-years across, and the smaller one, NGC 5394, is 90,000 light-years across.