Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

Monday, June 12, 2023

A glimpse of a monster

Ever heard of TON 618?

I hadn't until a few days ago, which is surprising considering my dual fascination with (1) astronomy, and (2) things that are huge and violent and could kill you.  TON 618 is a quasar, a luminous active galactic nucleus common in the universe's distant past.  Thankfully the cosmos has settled down a bit, because these things are so energetic their light is still visible today from billions of light years away.

Even by quasarian (I just made that word up, you should find a way to incorporate it into your daily speech) standards, TON 618 is impressive.  It showed up in a 1957 survey of faint blue stars, but its intense red shift indicated it was extremely distant and therefore a lot brighter than it looked.  It was entry #618 in the Tonantzintla Catalogue, a list of stars described in the bulletin of the Tonantzintla and Tacubaya Observatories in Mexico, and that's what gave it its rather unassuming name.

Once you start looking into this thing, though, you find it's anything but unassuming.

First, it's huge.  The black hole at the center of TON 618 is forty billion times more massive than the Sun.  If you put it where the Sun is, the entire Solar System would be inside its event horizon -- in fact, its event horizon is estimated at forty times the orbit of the planet Neptune.

Because of this, it has an impossibly high gravitational field, and is the center of a turbulent infall of matter.  This unfortunate gas and dust, as it accelerates toward its inevitable doom, is compressed and heated, emitting enough light to make TON 618 one of the most luminous objects in the known universe.  If the above comparisons weren't enough to blow your mind, TON 618 is estimated to have a luminosity of 4 x 10^40 watts -- about 140 trillion times brighter than the Sun.

It's also what is known as a Lyman-alpha blob.  This is another astronomical creature I just learned about, only found in the early universe (and therefore at this point, very far away).  The name comes from its extremely high emission of the Lyman alpha emission line of hydrogen, which has only been used as a tool for astronomers in recent years; it is so strongly absorbed by the Earth's atmosphere that it is essentially invisible to ground-based telescopes.  With the advent of orbiting telescopes like the Hubble, Kepler, and James Webb Space Telescopes, astronomers are finding more and more Lyman-alpha emitters in the distant (i.e. early) universe, but the debate goes on about what those emissions mean -- and why they aren't seen in nearby objects.

[Image licensed under the Creative Commons J.Geach/D.Narayanan/R.Crain, Computer simulation of a Lyman-alpha Blob, CC BY 4.0]

The most fascinating question about all this is where -- and what -- are quasars now?  The surmise is that for the most part they've settled down to become quiet, ordinary galactic nuclei.  But what about monsters like TON 618?  It's on the order of ten thousand times more massive than Sagittarius A*, the black hole at the center of the Milky Way; so if this eventually evolved into a galactic center, it would have to be one big-ass galaxy.

To put it in quantitative scientific terms.

Of course, there's no way to find out for sure.  When you look into the distance, you're also looking into the past, because the light that reaches your eyes (or telescope) took a finite length of time to arrive.  So you're always seeing things as they were, not as they are, and the farther away something is, the further back in time you're looking.  We're seeing TON 618 as it was about 10.8 billion years ago -- there's no way to know what, or where, it is now.

But that doesn't stop it from being an astonishing object.  The more sophisticated our instruments get, and the more detailed our scientific knowledge, the more weird and wonderful and magnificent the universe becomes.  

Even so, I'm glad that TON 618 -- whatever it is -- is located at a safe distance.  As fascinating as it is, it wouldn't make a good neighbor.


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