Useless Planets Society is a podcast that takes outlandish concepts about how you can tinker with the cosmos – from snapping the moon in half to inflicting a gravitational wave apocalypse – and topics them to the legal guidelines of physics to see how they fare. Pay attention on Apple, Spotify or on our podcast page.

For probably the most half, galaxies solely are available two shapes: spirals and blobs. Whereas spirals might be majestic considered from the suitable angles, the dearth of selection can get boring over the cosmic eons. So on this episode of Useless Planets Society, it’s time to spice issues up, galactically.

Our hosts Leah Crane and Chelsea Whyte are joined by Vivian U on the College of California, Irvine, an astronomer who research how galaxies evolve once they smash collectively and warp each other. In the true world, galactic collisions can create unusual swirls and many-armed behemoths, however over time the chaos from the smash-up leads to simply one other blob. To make a long-lasting change, we’ll want instruments with a bit extra precision.

That’s the place the supermassive black holes are available. They may be capable to carve gaps by means of the mud and fuel of a galaxy, creating extra detailed photographs. However gravity tends to complicate issues, and finally even these black holes would devour an excessive amount of matter and merge collectively, leading to one more blob. Maybe darkish matter might be used as an alternative to create an invisible scaffold that shapes the distribution of the common matter that we are able to see.

Constructing such a strange-shaped galaxy – particularly one not like something {that a} pure galactic collision would create, comparable to a galaxy with sharp corners or one in a recognisable picture like a giraffe – is perhaps a solution to sign to aliens or future astronomers that we’re right here and we’ve got unbelievable cosmic powers.

In reality, maybe this has already been executed to the Milky Means by some unusual alien pressure – in any case, we are able to’t see our residence galaxy from outdoors of it. We solely know its form by counting the celebrities that we are able to see in every path and constructing theoretical fashions, so we are able to rule out that our galaxy is within the form of a giraffe or one thing else wildly out of the peculiar. But when it have been, say, a sq. as an alternative of a spiral, it is perhaps troublesome for astronomers to inform the distinction.