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By looking at the galaxies in the sky, we know that our Universe is in expansion.

To understand what this means, you can think about a raisin bread baking in the oven. As the bread raises, the dough inflates and the raisins get further and further away from each other. The important point is that they move away from each other NOT because they are moving through the dough, but because the dough ITSELF between all the raisins is inflating.

Something very similar is happening in our Universe right now. You can think of the raisins as galaxies in the Universe, and the inflating dough as space between galaxies. So this means that, just like the bread, the Universe is expanding, which means galaxies are constantly moving further and further away from each other, not because they are moving through space, but because space itself is constantly expanding. (One consequence of this is that the further a galaxy is from ours, the faster it seems like it’s moving away from us, because there is more space that is expanding.)

Ok. Now, if we start running the clock of the Universe backwards, it means that the further back in time I go, the closer galaxies were to each other. And if I go far enough in the past, all the galaxies (or, more precisely, the stuff – mostly a gas called hydrogen – they are made of) were all clumped together in a very hot and dense soup. If I go even further back in time, all that soup was contracted at the same point, with basically no space at all. That is the beginning of the Universe, something called the Big Bang (currently, scientists don’t really understand what happens there).

Just after the Big Bang, there was a very short period (about 10^-33 seconds, or a billionth of a billionth of a billionth of a millionth of a second) where space was expanding crazily fast (exponentially, to be precise). It’s as if the raisin cake raised so much that it filled the whole observable Universe (literally). This short period of exponential expansion of space is called inflation.

My work is about inflation. How did it happen? Why? How did it stop? How did it shape and influence the Universe we live in today? What are its consequences that we can still observe?

Lately, I feel like there hardly are any typical days. Next week, I am going to Paris for a conference. For the past month I have been in sunny California, visiting the physics department at Stanford University. Before that, I was in Cambridge for a month, the month before I was in Montreal, visiting McGill University, and the list goes on… I’ve travelled across a ocean about every 3 months since I became a PhD student, and I’ve been on most continents. This is one of the best things about what I do: I get to see the world and meet people from everywhere on the planet. These days, I am getting ready to move across the Atlantic to Stanford, in California, where I will be a visiting PhD student next year.

Regardless, the research routine looks about the same on every continent (that is, if I’m not attending a conference!). The first thing I do in the morning is to have a coffee. A serious coffee. Before that I’m not human (believe me, you don’t want to know what I am). While I have my delicious coffee with my breakfast, I check my emails and look at the ArXiv, which is the website where all the new scientific papers from all scientist across the world appear everyday. It’s very important to sat updated with the research that is being done!

I then bike (or walk, or take the train, depending where I am) to work. Once there, the first thing I do is to feed my office physicist fish. Yes, I have a fish tank in my office, full of fish that help me work out my hardest problems. (Actually, they don’t talk much; I mostly stare at them, but somehow it seems to help thinking a lot!) Here they are, in my office in Cambridge:

The goldfish is Quark, there are three minnows called the 3 Neutrinos (because they are really small and hard to distinguish), and three very funny bottom feeders called the Joeys (they are the observers, so everything remains classical). Actually, they are not in Cambridge anymore, they just moved to California (yes, on the plane).

I usually spend my mornings looking at equations, doing calculations, coding on my computer, and getting confused when things don’t work. Then, in Cambridge, at 11 am everyday we have tea and coffee with all the members of the department (but, of course, I always have coffee). That a great opportunity to discuss recent scientific papers, various nerdy physics gossips, and everybody’s work. I usually attack someone with questions about my work for help, and that is always a great opportunity to get covered in chalk.

In the afternoons during term-time, I usually spend my time teaching (which is also a great way to get covered in chalk), marking, or preparing my classes. If I’m not teaching, I do things like reading recent papers, applying for different things (like funding…), discussing with my supervisor, asking questions to other members of the department, or having Skype meetings with my collaborator (who are based a bit all over the planet).

Around 4-5pm it’s time for coffee again (just writing this makes me want to have coffee…), and then I go back to staring at my equations for a couple of hours, until I’m so starving I have to go home and eat, or, if I was clever and brought dinner with me, until I get too tired or so stuck that it’s no use going on. At that point, my desk usually looks like this:

Once I get home, I Skype with my husband for couple or hours (that is, if I’m not in California, where he is currently doing a postdoc). Then I go to bed watching something funny or a BBC documentary (I really like the BBC Horizon, they are amazing!).