The ultimate key to unlocking the heart of the Milky Way

At the centers of galaxies, supermassive black holes reside.

But seeing into the Milky Way’s heart, especially from within it, presents challenges.

Our galactic plane is rich in dust and gas: opaque to optical wavelengths.

Shorter wavelengths, like X-rays, reveal emissions from the galactic center.

Flares and bubbles indicate an intermittently active engine at our core.

But at longer wavelengths, light is transparent to that intervening material.

Far-infrared maps indicate a complex network of gaseous and plasma filaments.

These are shaped by star-formation, supernovae, neutron stars, and black holes.

The largest black hole, however, emits no optical light at all.

We can identify its location from radio features that point back to it.

We can also infer its mass from the orbital properties of stars in its vicinity.

In the infrared, JWST reveals intermittent flaring activity: indicative of accretion and acceleration.

But to see its event horizon, we’d need a radio telescope the diameter of planet Earth.

In its place, we leverage arrays of telescopes all across our world.

By synching them together with atomic clocks, we make time-coincident observations.

Synthesizing them with interferometry, we’ve revealed our supermassive black hole’s event horizon.

With future observations, we’ll witness Sagittarius A*’s time-evolution.

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.

This article is featured on Big Think.