Perspective is everything. Even for the Hubble Space Telescope. As July 4th, approaches and all the hilarious mishaps that come with it (seriously folks, be careful) – Hubble released a new image showcasing stellar fireworks in a “skyrocket” galaxy.
Kiso 5639 looks like a rocket shooting through the cosmos for us. But it really resembles a “flattened pancake” (is there another kind?). It only looks like rocket because we are looking at it edge-on.
The same type of galaxy looks vastly different depending on how we look at it. Here’s NGC 5457, better known as the Pinwheel Galaxy.
That’s a top-down view of it.
NGC 4565 is also a spiral galaxy, but we see it edge-on.
What’s special about Kiso 5639?
Besides resembling a firework this close to the Fourth of July, what’s the big deal with Kiso 5639? Galaxies like Kiso 5639 are common, but we tend to find them much further away. This one is just 82 million light-years away.
“I think Kiso 5639 is a beautiful, up-close example of what must have been common long ago,” said lead researcher Debra Elmegreen. “The current thinking is that galaxies in the early universe grow from accreting gas from the surrounding neighborhood. It’s a stage that galaxies, including our Milky Way, must go through as they are growing up.”
Hubble’s Ultra Deep Field observations of the early universe has shown nearly 10% of all galaxies have these elongated shapes. Scientists call them “tadpoles.”
The glowing head of Kiso 5639 is made up of dozens of clusters of stars. The clusters at the head are less than 1 million years old on average. Older stars have formed in other parts of the galaxy, but are nowhere near as active as the ‘head.’
Why was Kiso 5639 slow to develop?
Galaxies like our own used to resemble Kiso 5639. What’s taking this galaxy so long? Scientists say it’s been drifting through a “desert” of little gas in the universe. About 1 million years ago, the leading edge slammed into a pocket of gas. This huge influx of matter kickstarted a stellar birth explosion.
Elmegreen expects other parts of Kiso 5639 to see similar development. “Galaxies rotate, and as Kiso 5639 continues to spin, another part of the galaxy may receive an infusion of new gas from this filament, instigating another round of star birth,” she said.
Elmegreen also explained what kind of gas the galaxy likely encountered.
“The metallicity suggests that there has to be rather pure gas, composed mostly of hydrogen, coming into the star-forming part of the galaxy, because intergalactic space contains more pristine hydrogen-rich gas,” she explained. “Otherwise, the starburst region should be as rich in heavy elements as the rest of the galaxy.”