How does one go about exploring a question as broad as how and why there is a universe? U of T’s professor Bob Abraham from the Department of Astronomy and Astrophysics encounters questions like these in his studies every day. Abraham recently sat down with The Varsity to share his drive to explore the universe.
When asked why he chose to specialize in observational cosmology, Abraham cites his fascination with the “big questions” posed in astronomy. He is mostly interested in the central issues that have occupied humanity since we “crawled out of the primordial slime.” In answering these questions, Abraham thinks cosmology provides an individual with perspective on the universe as a whole and his or her place within it.
As a fairly optimistic but skeptical person, Abraham is most attracted to the observational side of astronomy as opposed to the computational side because he would rather “study the universe from the point of view of seeing what’s actually out there, kind of doing this exploration through discovery rather than programming this stuff into a computer and seeing what the computer tells me is going to be happening… The universe is incredibly surprising, so all of this stuff is emerging just by going out there and looking.”
Abraham thinks this is a fantastic time to be an astronomer. “I have been amazed at how easy it is to make discoveries in astronomy. If you have a big enough telescope, you can open up vast new areas of the universe that nobody has ever looked at before and almost always, as soon as you start looking at bits of the universe that nobody has ever explored, you discover new things. [Astronomers] all band together … and build these gigantic telescopes. As a result, we can all have access to this kind of cutting-edge stuff, simultaneously [invigorating] the field.”
But Abraham doesn’t have to look too far to figure out what attracts him to astronomy. “The universe that you see around you is only like three per cent of what’s out there… Everything you see in this room is made up of atoms so you think ‘oh well, that’s the nature of the universe’ — but no! The stuff made up of atoms is only like three per cent of the mass of the universe. Ninety-seven per cent is made up of this stuff called either dark matter or dark energy… It just does not respond to light at all, so consequentially you can only detect it by its motions because it does respond to gravity, so the motions of things let you detect the presence of this dark matter stuff but you just can’t see it. Dark energy is this component of the universe that’s associated with emptiness in between the galaxies so it’s the part of the universe that looks the most empty, [but] at least in terms of the energy content of the universe, the most rich. It’s making the universe expand in its acceleration…”
Abraham recounts three interesting projects he has going on at the moment. The first project relates to a discovery by one of his graduate students who was recently admitted at Harvard for a post-doc position. The discovery is that in the early universe, galaxies were much smaller than they are today, even though they’re about the same mass. “Nobody knows why, so there are a bunch of possibilities, that people are writing about, but fundamentally nobody knows why.” Abraham and colleagues are currently analyzing data from the Hubble Space Telescope and data from many ground-based telescopes to figure out why galaxies become bigger as the universe gets older.
The other project is on figuring out how to exploit a technique called “adaptive optics.” This technique uses lasers and supercomputers to try to fix the blurring in earth’s atmosphere when trying to capture images from outer space. Ultimately, Abraham wants to be able to “take pictures from [Earth’s] ground that are as clear as pictures you can take with the Hubble.”
Abraham describes his third project with a colleague from Yale as “truly crazy.” “We think that galaxies are built up by crashing together little galaxies [that] smash against each other and then eventually settle down [such that] what you’re left with is a bigger galaxy. We think this happened to all sorts of galaxies, including our own.”
In order to study the remnants of these galaxies crashing together, he is trying to come up with a technique to use really small telescopes with expensive yet off-the-shelf camera lenses. He wants to try to use some of these lenses with some techniques he and his colleague are developing to visualize things that are really faint to look for the remnants of crashing galaxies.
As for his bucket list, one particular question Abraham would most like to have answered is the solution to Fermi’s Paradox. This paradox essentially boils down to one question: where the hell are all the aliens? Enrico Fermi was a famous physicist who worked out the possibility that a highly technologically-advanced civilization can at some point build a probe that could go to the nearest star. This probe may be able to replicate itself so that one probe could be launched out into space and then there would eventually be self-replicating probes throughout the galaxy. “The prediction is that the universe should be just teeming with evidence for advanced technological civilizations because all you really need is one [probe]. There’s no evidence for that that I can see, and so I would like to know why not?” Abraham wonders.
Another mystery Abraham would really love to have answered is why the universe emerged in the first place. “[We’ve] gotten to the point now where we’re really measuring things like the age of the universe, it’s composition, what it’s made of, the balance of the different things like the dark energy versus dark matter versus regular stuff, and so we’re able to understand these things, but we still don’t understand the initial reason for the existence of the universe. Interestingly, though, that’s now almost something that we can actually speculate about scientifically and not theologically. We’re kind of on the cusp of being able to answer those ginormous questions. Why did the universe emerge? Why did it have the properties that it has? I would [also] like to know why we’re here at all.”
When asked about the most outlandish hypothesis he could think of, Abraham replies that “the thing about being an observational cosmologist is you are grounded in the nitty-gritty of testable hypotheses, but you’re operating in an environment where the questions themselves are so outlandish… Even though I don’t do this every day, there are colleagues that I work with who sit down and try and come up with experiments to parameterize the first few microseconds of the origin of the universe to try to better understand why it emerged… You have to be a hard-nosed scientist with an appreciation of what the data is telling you, but at the same time, you’re dealing with these fantastically profound questions that sound outlandish but aren’t.” According to Abraham, “No idea is too outlandish, as long as it’s grounded in reality, as long as it’s testable. I reckon that astronomy makes progress through the continued use of outlandish ideas to move the field forward.”
