Early January is the time when thousands of astronomers get together for the winter American Astronomical Society meeting. It’s a chance to catch up on the latest and greatest astronomy discoveries and talk shop about things like black holes and stars and galaxies. As a member since 1992, I’ve been happy to attend those meetings . I go to partake of what we often refer to as “the firehose of astronomy information.”

Well, as you might guess, the ongoing COVID-19 pandemic has put a stop to those meetings for the time being. We came this close to having an in-person meeting this week in Salt Lake City. However, the humongous rise of infections due to the omicron variant of COVID-19 (and the continuing wave of delta infections) forced the meeting’s cancellation. But, it hasn’t stopped the flow of information. And, for that, I’m grateful—because there’s a LOT out there to talk about! And, as usual, black holes take center stage for at least part of the meet ing.

Astronomy and its Changing View of Black Holes

Back when I first studied astronomy, these cosmic monsters were not yet observed. Sure, people thought they might exist; they had theoretical and mathematical underpinnings as far back as the early 20th century. But, for a long time, nobody found them.

In one of my oldest textbooks, the writer devoted only one or two paragraphs to the possibility of such things actually existing. And, that’s entirely understandable. There wasn’t evidence or data for black holes, and thus, not much to say.

Today, we find them across the universe. Astronomers have managed to get at least one very detailed image of the region around a distant supermassive black hole. And, they’ll get more.

So, we have a LOT to say about them. So, what changed? We got more data about them, from actual observations. However, it turns out that you don’t really look directly at a black hole and detect it through an optical telescope. Nope.

Astronomers have to find them using indirect means. They look for high-energy radiation (x-rays, radio waves) from the regions around black holes. Or, they look at the motions of stars and clouds of gas and dust in the region around a black hole. Or, they might also look for any gravitational lensing effect from the black hole.

Black Holes at AAS

One of the stories from the AAS press conferences (which are going on even though the meeting isn’t), is about the role that black holes played in a period of time called the Epoch of Reionization. This was an era when the infant universe was just starting to “light up”.

Prior to that the everything existed in a period called the “Dark Ages”. That’s when the universe was a dense “fog” of primordial gas (mostly hydrogen). As that gas began to clump together, the first galaxies formed and the first stars were born. But, their light had to get out through that fog. It turns out that the earliest black holes could have played in an import role in this reionization process. Their extreme radiation may have punched holes in the cosmic “fog” of hydrogen. That allowed ultraviolet light from the earliest stars and galaxies to travel across the universe.

Now, we can’t see those early black holes. Their galaxies are too far away. But, astronomers have found a supermassive black hole inside a galaxy similar to the early ones. This black hole is quite powerful. If ancient supermassive black holes were anything like this one, then they could be part of what triggered the Epoch of Reionization.

Our Own Black Hole

Black holes at the hearts of galaxies aren’t just limited to the long ago and far away. They’re now pretty commonly known throughout the modern universe. This includes our own Milky Way. Its central, supermassive black hole lies about 26,000 light-years away from us. The object is named Sagittarius A* (or, Sgr A*, pronounced “Sadge A-Star” for short). It’s relatively quiet these days, but in the past, Sgr A* was much more active. It periodically gets busy and lights up its neighborhood as it swallows up stars and other materials that stray too close.

The evidence for that activity is found in clouds of gas (called “molecular clouds”). They lie at various distances close to Sgr A* and often “glow” in x-rays, emitted as the clouds get heated up by radiation streaming away from Sgr A. Essentially, whenever the black hole gets more active, that affects the surrounding clouds and they glow.

Science Moves Forward

These two stories (out of several being released) are really good examples of a concept called “Follow the science”. We’ve all heard it in relation to the ongoing COVID-19 pandemic. It’s as true for the black holes as it is for the scientists studying the virus. The more data we get about black holes, the more we learn about them and their activities. Astronomers now know these cosmic monsters played (and are playing) an important role in the evolution of the universe itself.

The same is true for the pandemic virus. The more we know about it, the more we can develop vaccines to counter it. (And, perhaps also convince people to GET those vaccines, wear masks in public, etc. to prevent an even more catastrophic spread of the disease it causes.

In terms of black holes, what we used to think about black holes is no longer as important as what we know now. And, it will be truly interesting to see what else we learn about them as astronomy progresses. That’s the role of science, whether its viruses or black holes: to progress, to teach us more about the universe in which we live.

As we all wait for the upcoming launch of the James Webb Space Telescope (JWST), now rescheduled to Christmas Day (or possibly a bit later), it’s worth examining some of the other science it could do. Although I am fascinated by the prospects for exploring the earliest epochs of the universe’s history, there’s another exploration that I like: exoplanet atmospheres. JWST should be able to examine the air at planets around other stars and suss out their atmospheric composition. Atmospheric gases related to life should be seen, which makes JWST a life probe. Kind of interesting, so stay tuned on that.

The Venus Atmosphere

Here in our own solar system, the search for life continues. We know it exists on Earth, and suspect it could have (or maybe still does) exist on Mars. Farther out, Europa and Enceladus remain tantalizing targets in the search for life.

But, what about Venus? Could its atmosphere tell us if life exists there? While there’s no hard evidence yet, despite some interesting finds over the past year or two (phosphine, anyone?), some scientists think it’s possible. I ran across an interesting paper a few days ago about the subject. It describes the research and a hypothesis from a group of scientists at Massachusetts Institute of Technology, Cardiff University (UK), University of Cambridge (UK), Cavendish Laboratory (UK), and the Medical Research Council in the UK. This team looked at some anomalies found in the Venus atmosphere and they came up with a possible pathway for life to explain those anomalies.

Let’s take a closer look, starting with those clouds. The principal component of the Venus clouds is SO2—sulfur dioxide. That makes them very acidic. However, there are some odd atmospheric anomalies just crying out for further examination. One of them is the existence of pockets of ammonia (NH3. The chemical signature for that gas was first found in the 1970s. Its existence remains something of a puzzle to planetary scientists.

The Source for Ammonia

Now, the ammonia isn’t coming from outside of Venus—it’s locally produced. It appears only in those sulfur dioxide clouds and not on the surface. As it is created, the amount of sulfur dioxide drops a little in the areas where the ammonia exists. In addition, there are small pockets of oxygen in the clouds. The question we all want to have the answer to: what’s making it?

There’s no obvious geological or mineralogical source for it. The ammonia doesn’t seem to be a by-product of the volcanic activity on the Venus surface, or of Venus lightning. So, they wondered if it could be due to life in the clouds? Or, are there other explanations that having nothing to do with life? Obviously, we need a lot more data to understand what’s going on.

Life in Venus Clouds

Let’s do a little thought experiment and imagine that the ammonia is due to some life process. The researchers took that idea and came up with a model. They assumed if the ammonia is present in gaseous form, then it would cause a set of chemical reactions in the atmosphere. If life is producing ammonia in the Venus clouds (NOT proven yet), one by-product of the chemical reactions is oxygen. The ammonia itself would dissolve into the droplets of sulfuric acid, which would neutralize them. In other words, that life could change acid rain to someplace where that life could happily exist. Essentially, it could be creating its own habitable zone right there in the Venus clouds.

Now, there’s a lot of research to be done to prove this idea. Or, scientists have to find some other logical explanation for the presence of ammonia and heightened amounts of oxygen gas in the Venus atmosphere. Fortunately, there are plans to send spacecraft to Venus to make extremely detailed studies of its clouds. The Venus Life Finder missions, headed up by MIT’s Sara Seager, will measure them to look at the ammonia and see if there are other signs that might point to life.

If you want to read a more detailed paper on the subject, the researchers have put it up online. You can also read the story at Phys.org, talking about the possible presence of life on Venus.