Astronomer Edwin Hubble pioneered the study of galaxies based simply on their appearance and categorized them according to three basic shapes: spiral, elliptical, and irregular. Some 60 years later, the sharp vision of the space telescope named in his honor began seeing unprecedented details in galaxies, revealing intricate, dark dust lanes and glowing knots of star formation. Hubble helped uncover the supermassive black holes that power the bright centers of massive galaxies, and revealed the interdependent relationship black holes have with their host galaxy.
Hubble has also captured merging galaxies that look like a “Great Pumpkin,” a “Space Triangle,” “Antennae,” and “Mice.” For all their violence, galactic collisions take place at a snail’s pace – over timescales that span several hundred million years. Hubble captures a mere snapshot of these mergers.
Hubble images of the “tadpole-like” Antennae and Mice galaxies reveal the gravitational turbulence these galaxies endure. The interacting duo called Arp 143 (the “Space Triangle”) holds a pair of distorted, star-forming spiral galaxies. Astronomers think the pair passed through each other, igniting a triangular firestorm of new stars.
Mergers like this preview the coming collision between our own Milky Way and the neighboring Andromeda galaxy 4 billion years from now.