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What is one aspect of astrophysics you wish more people knew about?
Astronomy != astrology (astronomy is not the same as astrology). Jokes aside - this is a fantastic question and made me think for quite a while. There's so many things that come to my mind. Rather than inundating you with my endless list, here is what tops my list, currently.
I wish everyone knew and believed that anyone who truly sets their mind to it, can be an astrophysicist, and that it is not nightmarishly hard as common media culture portrays it to be. Astrophysics isn't easy (but then what is? Life isn't easy - if it was, where would the fun be?). There are days when I'm left questioning every single thing I'm working on and yelling and swearing at my computer because the software I'm using has decided to throw a temper tantrum or because my piece of code is being a pain. Then there are days where I am filled with satisfaction although my research did not produce the results I wanted, or I didn't get as far as I wanted, because I know that I am here because it was my decision to become an astrophysicist and I am here, doing what I love, because I wanted this out of my life. Thirdly and finally, there are days where everything is hectic and busy, but things are smooth, like that perfect PowerPoint slide transition.
It is my personal opinion (at the moment) that astrophysicists (or researchers) are happier than the average corporate employee. Most people in the corporate sector are at the centre of the typical daily hustle of a 9-to-5 routine, sticking to NDAs, client demands, deadlines and striking that balance between self-satisfaction, achieving what a demanding market asks for, and avoiding topics of contention in everyday discussions. That is what I think is hard. And I have so much respect and admiration for my friends in this sector of employment.
As an astronomer, I think I may be one of the most selfish people on the planet as what I do doesn't directly benefit mankind. It satisfies me, aids in progressing my research collaborations, and contributes to mankind's curiosity about the universe, the world we live in, and answering the age-old question of where we come from. But it doesn't make the world rotate, or help bring food to a family's dinner table (my PhD stipend just about can though - it feeds two guinea pigs and an astronomer haha).
Astrophysics requires creativity, a ton of data science and data mining, and an appreciation of the backbone that is the underlying physics. All of these are skills and knowledge which can be developed and honed with time, patience, will-power, and a little bit of intuition.
I was once a five-year-old girl who set her mind to become an astronomer. She paved her path to become one (but not without the support of her guiding light and best personal cheerleaders, her parents). Everyone has their own set of odds to overcome, I sure had mine. Being a woman, and that too a woman of colour, in a male-dominated field, is challenging. LIfe also gets in the way, but life can get in the way of anyone trying to achieve anything.
Astrophysics isn't nightmarishly hard. Sometimes, life is.
What's your favourite object in space?
I’m a romantic – it’s the Rosette Nebula. Because it’s pretty and shaped like a rose and roses are a universal symbol of love. This nebula is a gas and dust cloud, dominated by hydrogen emission lines. This rich hydrogen environment is what makes it a breeding ground for star formation, which is further supported by the fact that the Rosette nebula is home to a cluster of young and bright stars, called NGC 2244. The image below is from NASA's Astronomy Picture of the Day, from 14th February 2021 (hands down the best date ever, pun intended). It shows the Long Stem Rosette Nebula, a wider image/portion of what is more commonly known as the Rosette nebula. Click the image to learn more.
How do they label or categorise objects in space that they discover?
Answer brewing, coming soon!
Are we living in a simulation?
Excellent question. I wish I had a definite answer. Short answer: there is no way we can verify this as of now. Long answer: read on!
I spoke to two of my professors, both theoretical physicists (shout-out to Prof. Mike Gunn and Prof. Martin Long) about an answer to this question over the last few months and in a nutshell, they both had the same thing to say - we might very well be living in a simulation but we cannot know this for a fact because the process of knowing this would imply breaking the simulation and stepping out of it. Breaking the simulation means breaking the laws of physics and currently, we don't really have a recipe for this. Perhaps a black hole or the Big Bang would be a good place to begin as they're both singularities (gravitational field so strong that the escape velocity is greater than the speed of light and the speed of light is the universal speed limit, plus the math breaks down - this is no fun) and our laws of physics are still a work in progress when it comes to understanding what goes on inside them.
Now for my view on this. Before I dive into it, here's a brief summary of my philosophical/spiritual/religious worldview. I am Hindu, and I have a knack for spirituality and the idea of creation and a Creator. I believe that everything that exists, has been created by some mechanism. I believe in science and energy above everything and this is what drives my scientific thirst and career. I lean a bit more towards the idea that we do indeed live in a simulation. One thing which has always bothered me, and still does, is why does the universe bother to exist? If laws of physics tend to equilibrium, the ultimate and most efficient equilibrium would be having absolutely nothing at all. This means there must be something/some energy out there which is literally eating popcorn while watching galaxies and stars pop in and out of existence for fun, as everything attempts to get to equilibrium again. My feeble, finite brain cannot fathom any other reason for the mind-boggling detail and intricacies of the universe and the laws that govern it. Science may get us the answers to this some day, I think this day is quite distant, but some day the simulation will need to restart/might need some bug fixes, not unlike a Sims game, and when it does, we may get a glimpse into the simulator/architect, and that may shed a fleck of understanding.
If you, like me, are unsatisfied with this answer and wish to read more, do check these out:
1. A paper titled 'Probability and consequences of living inside a computer simulation'
2. A Forbes article titled 'Are we living in a simulation'
3. An article from The Conversation with ideas on how to test if we live in a simulation
What is the Universe expanding into?
Answer by Anwesha Sahu
*Warning: This answer may be a bit disheartening*
Nothing. The universe is expanding into nothing. As suggested by cosmological models, the Universe seems to be finite. Its start was marked by the Big Bang about 13.7 billion years ago, in a cataclysmic explosion that breathed life into the Universe as we see it today. The universe is expanding to this very day. While cosmology tells us that the universe has a curvature (there are three sub-categories of curvature which may be visualised as these: a pringle, the surface of a basketball, or flat), another key facet is that the universe effectively has no edge. This is sort of like if you were a beetle and decided walk across the surface of a basketball, you would never reach the end. Since the universe has no edge – brace yourself, this answer may be disheartening – the universe is all that there is.
One of the first key points they teach you in an introductory course to cosmology in undergraduate is that the universe is homogenous and isotropic. All that this means is that universe is (roughly) the same at every location and looks the same in all directions. The Cosmic Microwave Background supports this. So remarkable is this signature of the Big Bang that the temperature variations are only of the order 0.00001K. This homogeneity is a contributing factor to fuel the Big Bang hypothesis.
What existed before the Big Bang? What ‘container’ did the Bang occur in? Quite frankly we have no clue. It’s like questioning some higher authority asking them the reason why we are born without our own permission. We simply don’t have control over it. I can’t tell you how badly I wish I had an inkling of an answer to this question. In fact, it was this very question which made me choose to pursue my degree specialising in particle physics and cosmology.
As a sidenote, this article does a pretty neat job of explaining this: https://phys.org/news/2013-11-universe.html. One point I would be wary of is that this article juxtaposes itself. Nothing can travel faster than the speed of light even though at one point in the article they make the reader assume for a second that that is possible. While Einstein tells us that the universal speed limit is obeyed by all objects in the universe, there’s a pretty sleek loophole to this. What about the universe itself? Can it travel faster than the speed of light? Absolutely. And that’s what’s observed. Space itself can expand faster than the speed of light. Hence, to catch up to the supposed ‘boundary’ of the universe, you’d have to travel faster than the speed of light which is simply forbidden. It’s like walking on the surface of an expanding balloon – everything keeps getting further and further apart from every other thing faster than the things are travelling towards or away from each other.
So, as far as we are concerned, the universe is all that there is. It is not expanding into anything. It simply is expanding.
Will physics provide concrete answers on meaning and existence or will this always be within the realms of philosophy?
Answer by Anwesha Sahu, with inputs from Prof. David Evans, University of Birmingham, UK
I am going to delve a bit into my own perspective of this first. Meaning isn’t something that the Universe or physics give us. Meaning is what we give to observed entities. Red is the colour of blood. Blood is often a sign that something has gone wrong with the physical human body. Hence, red signifies danger. The colour red never inherently meant danger. We associated this with it. Science simply tells us that red is the range of the visible electromagnetic spectrum with wavelengths in the range of roughly 620nm to 750nm. Similarly, science and physics probably will not give us concrete answers about the meaning of the Universe’s existence. Whether this is a blessing or a pain I do not know, but we have the phenomenal ability as beings with consciousness to extract a meaning from the phenomena observed in the Universe. Perhaps this is the universe’s way of giving meaning to itself.
The meaning of existence packs within itself such a punch that by the day we figure this out, chances are that we will have been wiped off the face of the planet or the universe as we see it. Existence is something that we have to face. It is thought that when we are born, we are born with a ‘clean slate’. I like to picture it as though our experiences, decisions, and life choices paint the picture on the slate. What gives meaning to this picture is our interpretation of it. If the slate shows a picture of a lone mountain top, one may find solitude and satisfaction in it while another may see piercing loneliness.
I don’t think that the answer to this question will be given by science or philosophy explicitly. Science and philosophy teach us to hypothesise, experiment and deduce. The universe is the ultimate playground full of innumerable phenomena for us to observe, experiment with and analyse. That’s what’s been done in the case of the gravitational wave detection with LIGO and with exoplanet detections by the Kepler satellite in foreign planetary systems. If we observe an exoplanet which seems to have organic compounds, we assign to it the fact, or meaning, that life may exist on this newly discovered world (and unwittingly we also assign newspapers their science headlines for the next day and Google the bulletin news notifications that will make their way to millions of smartphones). Giving meaning to the discovery is the job of psychology because the very act of giving something a meaning is to bias our perspective of it. The meaning of life and your existence is your slate and the picture is what your experiences and thoughts have painted on it. Life is about experiences, meanings of things just tagged along for the ride.
I asked Prof. David Evans, a particle physicist in the School of Physics and Astronomy at the University of Birmingham about his views on this and here’s what he has to say. Prof. Evans says “physics is about constructing mathematical models to explain how everything in the universe works, why things behave they way they do, and to predict other, as yet unmeasured, phenomenon”. Making predictions and deductions has led us to ‘the modern age with modern technology’ and while science may eventually explain how life came to be the way it is and may even explain what consciousness is, it “will probably never explain why or how the universe began (i.e. what caused the Big Bang?)”. He concludes,
“In terms of the meaning and existence, I think if science did come up with an answer, it wouldn't be a popular one. I think it's probably better (or at least more satisfying) to stick to philosophy in this case.”
How do rollercoasters work?
Answer by Anwesha Sahu
Why do some parts of the electromagnetic spectrum get more work/telescopes than others?
What a fun question! Before diving into explaining why this is the case, let's see how viewing the universe in different wavelengths of the electromagnetic (EM) spectrum gives us insights into different physics.
The EM spectrum is the full range of energies and wavelengths for electormagnetic radiation. My physics teacher in high school, Mr Peterson, taught us a very handy mnemonic to remember all the regions in order (I challenge you to not burst out laughing while visualising this mnemonic): Rabid Monkeys In Venus Use X-ray Goggles. Going from long wavelengths to short, the first letter of each word represents the following, in order: radio, microwave, infrared, ultraviolet, x-ray, gamma. Longer wavelengths correspond to lower frequencies and lower energy levels. Hence, gamma rays are the most energetic form of radiation. The figure below shows the different regions of electromagnetic spectrum, with some examples (Source: Britannica)
Telescopes can be built to be sensitive to different regions of the spectrum. The standard telescope with a classical mirror and lens will observe objects in the visible/optical region. If you own a backyard telescope, it is an optical telescope. With our naked eyes, we see things in the optical region. However, the universe emits light across all regions of the electromagnetic spectrum. So observing things in different wavelengths allows us to probe different energy scales.
The mechanism for constructing telescopes for each of the regions is different, and the amount of radiation emitted in each region is different. This is the reason why different regions of the EM spectrum have different observing strategies. A lot of information can be obtained with optical wavelengths, such as information on the elements present in a celestial object, and electron energy transitions resulting in different colours of light being emitted. Hence, optical astronomy gets a lot of focus, in the astronomy community. Studying the different colours in the optical region is called optical spectroscopy. Studying brightness changes (regardless of colour changes, just the overal brightness intensity) is called photometry. Photometry can allow us to track the evolution of different astronomical events, such as brightness changes in a supernova explosion, thus aiding in understanding the underlying physics. The practical costs associated with optical telescopes is also significantly lower than that for other wavelengths such as radio and x-rays. For instance, x-ray and gamma ray telescopes work best when situated in outer space, while radio telescopes work in arrays of tens of telescopes. Combine the effects of the above and optical astronomy becomes the most easily accessible form of astronomy data collection.
