When galaxies collide with one another they are absolutely cataclysmic events and experts believe our galaxy, the Milky Way, was part of one of these at some point in its history. Now, recent data from the Gaia satellite is showing astronomers what might have happened and explain some anomalies we've detected in the past.
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00:00When galaxies collide with one another, they are absolutely cataclysmic events, and experts
00:09believe our galaxy, the Milky Way, was part of one of these at some point in its history.
00:14Now recent data from the Gaia satellite is showing astronomers what might have happened
00:18and explains some anomalies we've detected in the past.
00:21The Milky Way's galactic disk has an S-shaped bend, something first noticed way back in
00:25the 1960s.
00:26For decades, experts weren't sure why this bend existed, or why it stretched nearly a
00:31quarter of the way around the entire galaxy, including altering the movement of tens of
00:35thousands of stars.
00:37Now they say it's likely because this is the resulting shockwave propagating throughout
00:41the galaxy, the remnants of a previous galactic collision.
00:44They say there are two distinct movements happening in the galactic ring, one back and
00:48forth and the other up and down.
00:50They say this is similar to how ocean waves move, independent of a tsunami underneath.
00:55However, this one doesn't drag water, but entire star clusters, forcing them to deviate
00:59some 6 to 9 miles from their intended paths every second.
01:03Recent research suggests that the Milky Way's last galactic collision occurred just 3 billion
01:07years ago, meaning Earth was likely already around when it happened.