In the Netherlands it’s traditional to print up like 200 copies of the thesis in soft-bound B5-size (6.8-9.8 in) and hand them out to everyone at the institute (the API has 100+ people), your close friends and family, and mail some to collaborators and close colleagues. It’s almost like your business card. I have about 20 PhD theses of people who graduated from API before me while I was there, and it’s really nice to finally get to pass out a thesis of my own.
My public PhD defense, reception, and party are Thursday April 19th in Amsterdam! If you’re around and would like to come, please contact me via email or Twitter to get the details! Only 6 more days to go!!!
I got into podcasts maybe 6 months ago (I know, I’m like 10 years late to the game), and I really love them. I listen to them when I’m waking up and getting ready in the morning, driving, doing chores or tasks around the house, and working out. My podcast app of choice is Podcast Republic for Android, which lets me play episodes through my Chromecast when I’m at home, and it saves the podcast files to my phone’s SD card (where there’s a lot more space). Below are a list of my favourite podcasts so far (in alphabetical order) with a particularly great recent (or recent-ish) episode.
The gist of it: Invisible forces that shape human behavior Recommended episode:“I, I, I. Him.”
My Brother, My Brother and Me
The gist of it: Horrible advice for hilarious questions, or hilarious advice for horrible questions I generally like all of them (except the live ones). If you’re new, ignore the backlog and just start listening.
Back in May 2017, I was part of a Science-Art Slam in Amsterdam, organized by Claudia Mignone. Three astronomers/astrophysicists (David Gardenier, me, and Daniele Gaggero) gave 20ish-minute talks about our research, while at the same time musicians were creating free-improvisation music and a visual artist was mixing live projections of related scientific images. It was a super fun and different outreach-type event to both experience and participate in!
I talked about neutron stars, black holes, and their extreme environments. The transcript is below the embedded video. Enjoy!
I’m Abbie Stevens, I’m doing a PhD at the University of Amsterdam, and I’m going to tell you a bit about what I’m doing it on. So I’m gong to tell you about neutron stars and black holes and the weird space around them. Black holes you’ve probably heard of, but neutron stars you maybe haven’t. David [the previous speaker] talked a little bit about neutron stars. This will be a story in two parts: first, what neutron stars and black holes are, and second, how we learn about them and how we know the things that we know.
Part 1: What are they?
When a star dies, it will turn into one of three things, depending on how massive it is: a white dwarf, neutron star, or black hole. if it’s up to 8 times as big as our Sun, it turns into a white dwarf. Most stars fall under this category and will become white dwarfs (including our Sun). A white dwarf is roughly the size of the Earth, but it has almost as much stuff as in our Sun.
If the star is a bit more massive than that, up to about 20 times the mass of the Sun, the star will go supernova and what’s left is a neutron star. A neutron star is very dense. It’s only 25 kilometers in diameter, but has 1.5 to 2 times the mass of the Sun inside it. It’s average density (how compact it is; the amount of stuff per volume) is on par with an atomic nucleus, and it’s inner core is denser than an atomic nucleus. To get an intuition for this kind of density, imagine taking every person on Earth, and squishing them into a 1 centimeter cube. I’ve calculated it, and it gets you in the right ballpark. This extreme density causes the neutron star to warp spacetime. Albert Einstein’s theory of general relativity, which is the leading theory of how gravity works, says that matter tells spacetime how to bend, and the fabric of spacetime tells matter how to move. So in this framework, a neutron star is massive enough and dense enough to bend spacetime by a decent amount. And then, the curved spacetime causes the light and matter near the neutron star to behave in strange ways.
So let’s talk about a neutron star’s gravitational field. The acceleration due to gravity, which is a way of measuring the strength of a gravitational field, at the surface of a neutron star, is 100 billion times stronger than at the surface of the earth. If you dropped your phone on earth from 1 meter up (or if you’re Dutch, 2 meters up), it hits the ground in a couple milliseconds. If you did that from 1 meter off the surface of a neutron star, it would drop so fast, from the strong gravity, that it would hit the surface in 1 billionth of a second. Also, your phone would break. The work that you do against gravity hiking Mt. Everest on the surface of the Earth, is the same as what it would take to hike 1 thousandth of a millimeter on the surface of a neutron star (assuming you had a magical space suit that allowed you to not be totally pancaked to start with).
And then, black holes are weirder than that. A black hole is the remnant of a massive normal star, more than 20 times the mass of our Sun or even bigger. The black hole is what’s left over after it’s gone supernova.
Some black holes are 6 to 10 times as massive as our Sun — these are the small ones, stellar black holes. These ones are a few kilometers across in diameter typically, maybe 2 or 3 kilometers. The first black holes discovered by LIGO, the gravitational wave detector, were about 30 times the mass of our Sun, and they combined to make a black hole that was about 60 times the mass of our sun. Remember, there’s a lot of stuff in the Sun to start with, and this is 60 times that! And then there are the supermassive black holes at the centers of galaxies, that are millions or billions of times the mass of our Sun. The supermassive black hole at the center of the Milky Way, called Sagittarius A* (said “A star”), and it’s about 4 million times the mass of the sun, but only about 30 times the size of the Sun.
As you’ve maybe figured out, black holes are more massive and even denser than neutron stars, so they bend spacetime even stronger than a neutron star, and then again, light and matter behave even more strangely around them. But unlike neutron stars, black holes don’t have a hard surface. The size I’m referring to here is for the event horizon. This is the point, or rather, the surface, of no return, where the gravity is so strong that not even light can escape. So while black holes have stronger gravitational effects, there reaches a point where we have no hope of ever knowing what is inside it, so in some senses, neutron stars are more interesting to look at.
Now I’m going to take a step back and tell you how we know this, and how we learn more about neutron stars and black holes.
Part 2: How do we learn about them?
Black holes and neutron stars tend to exist in binaries with normal-type stars like our Sun. So you’ll have a neutron star or a black hole and a normal star that are pretty close together and orbit each other (kind of like the Earth and the Moon orbiting each other). But the gravity of the neutron star or black hole is really strong, so if it’s close enough to the normal star, the outer stuff of the normal star becomes more gravitationally attracted to the neutron star or black hole than it is to it’s own star, and the star stuff falls towards and swirls around the neutron star or black hole. So this process of draining the normal star and feeding the black hole or neutron star is called accretion, and accretion is a very powerful astrophysical process.
The star stuff that’s being accreted forms a disk around the black hole or neutron star (almost like the rings of Saturn, but thicker and bigger), and there’s a lot of friction within the disk that makes it get really hot. Now when anything is hot, it shines energy. For the human body, we shine most of our heat energy as infrared radiation. Like with infrared cameras or night-vision goggles, people glow brightly because of the infrared heat. The sun is hotter, and it shines most of its heat energy in visible light. And this accretion disk of hot star stuff, the inner part that’s close to the black hole or neutron star, is so hot that it shines most of its heat energy as X-ray radiation. The same energy the doctor uses to take pictures of your bones. This X-ray-hot part of the accretion disk is also the part that is sitting in the bent spacetime, the strong gravitational field close to the black hole or neutron star. We’re talking within hundreds of kilometers. So if we study the X-ray radiation, it can tell us how the stuff is moving and behaving in strong gravitational fields.
But, we can’t just take a picture, because this interesting region around black holes and neutron stars is both very small, and very far away. If you take a typical distance for one in our galaxy, it would be like trying to resolve the width of a human hair on Mars at closest approach. We can’t do that. So on the sky this looks like a single dot, or a single pixel. But, the X-rays aren’t constant – they flicker and wiggle and vary in brightness, and these variations are fast – tens to hundreds of times per second.
If you look at a particular black hole of neutron star with an x-ray telescope for a few hours, you can build a variability picture of these flickers and wiggles in X-rays, and some interesting patterns emerge. There’s noise that can look flat or like some weird lumps, and we think this is from stuff in the accretion disk gently flaring in brightness as it moves its way in toward the black hole or neutron star. There are pulsations in some neutron star systems that David talked about, from very regular brightness changes. Neutron stars have really strong magnetic fields (thousands of times stronger than anything that’s ever been created in a lab on earth), and the magnetic field can cause a lighthouse effect where you see regular bright flashes when the north or south pole is pointed towards you. Some of the pulsations happen hundreds of times per second, so you have a neutron star that’s 25 kilometers across spinning hundreds of times per second! Neutron stars that show pulsed light like this are called pulsars, and Claudia [Mignone] will tell us about the discovery of pulsars in the last session.
Then for both neutron stars and black holes, there are quasi-periodic oscillations. So they have a bit of a period, but they’re not very precise. Not quite periodic, not quite noise. But you could almost think of it like a changing heartbeat in the accretion flow. There are lots of types of quasi-periodic oscillations, so that the combination of quasi-periodic oscillations and noise in the variability picture is almost like a fingerprint. I have one colleague who has an nearly photographic memory for the variability pictures. You can show her one, and she says “that’s that black hole from 2010” or you show her another one and “oh it’s this neutron star from 2002”. And we think that the quasi-periodic oscillations are telling us about a hot fluffy flow of star stuff that’s piling onto the neutron star or black hole, and it’s wobbling around from being in the really strong gravitational field.
So we have these X-rays that are coming from this hot star-stuff that’s around neutron stars and black holes, and it’s spinning in curved spacetime. So by looking at these X-rays, they can tell us more about what black holes and neutron stars are, and how they make matter do weird stuff.
If you’re interested, I have some 3D-printed accretion disks that you can play with during the break.
I’m finishing two papers/chapters in the coming two months (well, finishing one and starting and finishing another, but the last is on NICER data so I’m pretty pumped about that). And also writing my thesis intro and conclusion. And also moving from the Netherlands to the US. Oh and holidays and family time. It is A Lot. It is Too Much! I have to do it anyway. My thesis will be submitted in mid-January and I’ll be defending on 19 April in the Agnietenkapel in Amsterdam (it’s a public defense that all are welcome to attend, and believe me there is going to be a GIANT PARTY that evening).
I am doing precisely as well as one might reasonably expect of someone undergoing all of this, namely, I am beyond stressed. I don’t know how I’m functioning. Every potential panic attack I fend off is a victory. Every hour of sleep I get is a victory. Everything else in my life is on hold. Please do not ask anything of me.
In February and March and early April (after submitting before defending), I’m going to put together blog posts here on advice on finishing your thesis (specific to the Dutch system) and my favourite blogs and youtube channels. I’m going to be able to commit serious work time to Stingray and astroquery.heasarc. And organizing my Evernote and Pocket. Oh and taking some time to chill out and go on a little vacation.
I’m at the stage of my PhD where I’m finishing research for and writing up my last two chapters (and then putting together a broad intro and conclusion for everything), and writing two fellowship applications, and sometimes I have trouble focusing on what I’m working on. I asked my wonderful friends on Twitter and Facebook who’ve written theses and papers for their advice, and it’s all so good! So I’m sharing it with you! It has been lightly edited for flow.
(And yes, I know I’ve written two theses and two first-author papers before. Apparently I’ve blocked it out.)
Make a plan
“Maybe make an outline with just the section, subsections, etc first, and then fill in. It’s actually a good idea to do that as soon as you are pretty sure the results will turn into a paper.” – Tom Maccarone via Facebook
“Lay out a timetable with achievable goals for each day/week and stick to it. Also vary what you’re doing, one paper one week another the next.” – Lucy Heil via Facebook
“Make an outline to keep it organized and keep you on track. I also don’t write in order. I’ll start at the end and jump around based on how I’m feeling. What also works for me is a change of setting or writing in a notebook instead of staring at a computer screen.” – Desi Paynter-Plivac via Facebook
“When I have a big deadline, I find it helpful to really use a daily planner and write in everything, especially those things that always seem to distract me (social media, email, housework, etc). I give myself a set time of the day to check email or Facebook. When I’m tempted to go there, I remind myself, ‘no, you get to check Facebook at 4, not now.’ I actually need to do this more.” – Rachel Frey via Facebook
“For myself, I know I can’t get myself to write papers that don’t tell (compelling!) stories. So I’m very selective about what I take on.” – Richard Scalzo via Twitter
Break it into bite-sized chunks
“Don’t make the thesis a goal. Make a small piece the goal, and then move on to the next goal.” – Tom Maccarone via Facebook
“DO NOT sit down with ‘write the whole thing’ in your head. Focus on a small part, e.g. spectral calibration with Blobbo spectrograph.” – Matt Kenworthy via Twitter
“Break it down to many small components (more than 10) and establish rewards for each (a walk, baking, TV)… Good luck!” – Anne Pasek via Twitter
“Break it down into small chunks and have lots of treats to keep you going. Stu usually had a chocolate bar in the car for me when he picked me up from the office. Also, it’s hard but take a small break either when you can or get someone to make you take one. So don’t eat at the desk, grab lunch or a coffee elsewhere. Gives you a chance to come back fresh. Evens if it’s only 5 mins, it can make a huge difference. I know it’s hard to take them but it’s better for you in the long run.” – Jeanette Gladstone via Facebook
Just start writing
“Try a free write. For me, this works best with pen and paper in longhand. It works like this, just set a goal. It can be time (e.g. 10 minutes) or a number of pages (e.g. 3, longhand) and write whatever comes to mind. Write all the distracting thoughts. Write your dream from last night. Write how much you hate writing. Write what you wish you could write in your thesis. I find this gets all those distracting thoughts out of my head. Most of that I write in my free writes is crap. But occasionally something good comes up. And when that does, I just copy to my computer. But I don’t expect anything there to be good.” – Rachel Frey via Facebook
“I like starting with writing the results section, or even just the captions of my figures, because the results are the exciting bits. 🙂 Basically, just start anywhere that feels manageable to you, and make sure you give yourself plenty of rewards. Writing papers is hard!” – Daniela Huppenkothen via Twitter
“Try distraction free writer, say ommwriter or google for free one. Pomodoro it. 29 minute timer, shut off all other windows. Just write. Then get out of your chair and stare outside.” – Matt Kenworthy via Twitter
“Often writing gets me in the flow, and at least it avoids spending hours/days staring at a screen. I’ve always found ‘just write’ to be solid advice. Forcing yourself to write something, even if it’s not perfect / needs to be rewritten.” – Vincent van Eylen via Twitter
“Don’t write it in order, write the bit you have the idea for. Also don’t force yourself to write if you have no inspiration, sort figures etc. until you do and then write whilst you have the thought. Don’t try to edit as you go along, get all ideas down then go back and reorganise. That’s what worked for me.” – Charlie Feldman via Facebook
“I forced myself in a harsh way to sit every day and write. No calculations, no data, no anything else, but writing only, and I forces myself to write at least 2 news pages every damn single day even if I rewrote previous pages, the manuscript has to increase by 2 text pages no matter what (I do remember how some days were very long…, that period took about 3 months) and then another 3 months went into polishing it.” – Natasha Ivanova via Facebook
“I managed by hitting up a coffee shop everyday for 3 hours. In those three hours, at least three paragraphs must be written. Why only three as my limit? Realistic expectations. Better off with few solid paragraphs than pages of BS that have to be rewritten!” – Hoang Pham via Facebook
Take frequent breaks
“On big projects, I set a timer for 20 minutes, write as many words as I can in 20 minutes, & edit it later. Easier to edit than from scratch.” – Diana Crow via Twitter
“Something like the Be Focused mac app where you only focus on a specific task during each, say, 25 minute slot and don’t do anything else. Then take a break when the time is up. This helps me so much when I’m really struggling to focus.” – Emily Petroff via Facebook
“I don’t use it myself, but I know a lot of people who use the Pomodoro timer. It makes you work for 25 minute blocks of time and then take a break. Good to use if you feel like you don’t know where to start or the project feels too big.” – Emma Gonzalez-Lesser via Facebook
“I use timers all the time. For everything. Any task that seems overwhelming isn’t so bad if you tell yourself, ‘I’m only going to work for 10/15/25 minutes, then take a break and do something else.'” – Rachel Frey via Facebook
Save the rest for when you’re feeling out of it
“When you can’t write, make figures and tables. Better yet, always make them first.” – Maria Womack via Twitter
“You can always put together what you have. Plots, method..previous work. Even outlook. Just get writing. Don’t expect to be super-motivated before writing. It’s ok when it feels like a drag. Start anyway. For me motivation comes with writing.” – Ludmila Carone via Twitter
“Inserting the references, figure/section/equation links, etc… is another such thing. I prefer just to have placeholders when writing to not disturb the flow. Then do the ‘dumb’ things when I’m tired.” – Remco de Kok via Twitter
Mix it up!
“Switch locations where you’re doing the writing, for me it’s easy to burn out a place and get into an unproductive rut. When I was writing my thesis I’d rotate between the office, the Library, home, and a coffee shop as I burned each place out. If you have multiple papers on the go, procrastinate on one, by working on the other.” – David Tsang via Facebook
“Have a token or clothing item that you only wear while you’re working on your thesis. I had a thesis scarf that when the scarf went on it was time to work. Also then other people can see you’re wearing your thesis scarf and they leave you alone (a friend had a thesis tiara which was arguably better).” – Emily Petroff via Facebook
“Steve Reich and standing desks. Music for 18 Musicians and Electric Counterpoint – makes you feel like everything you are writing will change the world.” – Brian Barth via Facebook
“Okay this may sound crazy but I was once in a class where we did yoga for focus and it was really helpful. You do like 2-3 minutes of sun salutations while focusing on a small goal, then immediately sit down and do it. You slow your breathing and heart rate down and clear your mind and then it becomes a lot easier to focus. Repeat as needed.” – Anna Lenti via Facebook
Take care of yourself
“Be kind to yourself and know that some days you won’t write very much and that’s ok.” – Benjamin Pope via Twitter
“I’ve found that having a ‘thesis buddy’ really helps me. She and I chat about how much progress we’ve made (a positive conversation) and sometimes meet up and write together in the library to stay motivated. I’ve also found that working somewhere with natural light helps me stay focused.” – Mackenzie Jones via Facebook
“Making your work environment as pleasant as possible is important. Whatever makes you feel good…a nice flower on your desk, scented candles, pictures of your loved ones, a hot cup of coffee… Whatever it is, but put it on your desk and make your work place your favorite place to go to. Also when I lacked inspiration, I would just take a break, walk through the woods and get back to work later. If you’re into essential oils….lemon and peppermint help with focus and mood! You can do it!!!” – Silvie Solana via Facebook
Writing this up as a blog post was one of my treats to myself for fixing some giant tables and making a big detailed combo-plot! As you can see in the top photo, I took Silvie’s advice and turned the spare room into a writing corner — so far it’s working! Good luck hugs to everyone else who’s writing up 💖💖
Back in May 2015 I visited Warsaw, Poland for work (visiting the Nicolaus Copernicus Astronomical Center), so I checked out the city during a little bit of free time that week! Here’s a quick list of what I did and loved:
See and do
Walking around the Old Town
I got a map at the tourist info booth, and went on a self-guided walking tour of the Old Town. I also recommend Rick Steves’ tour guides and travel advice. Warsaw had some cool artsy shops along the side streets, and I got a really nice pair of earrings in one!
I also walked along the wall of the Warsaw Jewish Ghetto and a nearby outdoor photography museum to the uprising. I didn’t go into any museums since my tourist time was quite limited.
Marie Skłodowska Curie’s birthplace
For many people, Marie Skłodowska Curie’s the only female physicist (or even female scientist) they can name. As fellow #womeninSTEM I stopped by her birthplace, which has a nice mural on the outside!
On the afternoon before we left, I hung out in one of the public parks and read my book for a bit. It was grey and a touch drizzly, but I sat on a bench under a big tree, so I still had a nice time.
The giant palm tree
There’s a giant palm tree in a traffic circle on your way from the astronomy institute into the old city. Palm trees aren’t native to Warsaw…
E. Wedel drinking chocolate
It’s not “hot chocolate”, it’s delicious molten drinkable chocolate. I happened to read about it in a travel forum when googling “what should I see in Warsaw” while I waited for my flight here, and I’M SO GLAD I DID. I recommend starting off with the classic milk chocolate, and on subsequent visits you can up your game (we visited maybe 3 times during the week). There’s an E. Wedel cafe in the Old Town.
We ate pierogies for most dinners, because PIEROGIES ARE DELICIOUS and honestly part of the reason I decided to go on this work trip was to gorge myself on pierogies. Zapiecek Polskie Pierogarnie is a local restaurant with a few locations around Warsaw, so we kept going back to different ones each time so that the staff wouldn’t begin to recognize us.
Since Polish as a language is very different from any other languages I’m familiar with, I found it was best to have a small notebook and pen in my purse, so that I could write down where I wanted to go to give to the taxi driver or when asking for help. Some adults speak a bit of English, but don’t assume that you’ll be able to get by easily.
Also, if you like makeup: there’s a huge Inglot counter in the Warsaw airport duty-free! Their lipsticks are excellent.💄
It’s tulip season in the Netherlands!! So on a sunny day off at the beginning of Easter weekend, we went for an afternoon-long bike ride through the tulip fields (or more generally, bulb fields) in South Holland, a province of the Netherlands. I recommend going in the middle-to-end of April for optimal spectacular sights, but as many guidebooks will tell you, anytime mid-March through mid-May should still yield picturesque views.
Since I live in Amsterdam, we didn’t want to cycle alllll the way there and THEN cycle around, so we started in Sassenheim, a town between Amsterdam Schiphol airport and Leiden. It costs about €6 on top of the normal train fare to bring your bike. If you’re just visiting and don’t have your own bike, you can rent bikes at the airport or Keukenhof gardens and cycle from there, rent them in town and take them on the train, or if you live in the Netherlands, rent them at train stations with OV-fiets. A cruiser bike or road bike is fine for this trip — no need to have a fancy off-road bike.
I consulted these sites to determine the best route for us: Holland Cycling, Tulips in Holland, and The Spinlister Blog. Most of them make use of the bike path network, which has numbered points (knooppunten) with various connecting routes. The route mapped above is 30 km (18.6 mi), which takes about 2 hours without stops. Keep in mind though, you’ll stop frequently to take photos and enjoy the view! I encourage you to use the Fietsknoop app to plan the above route (unfortunately I can’t embed it as a navigable map) or make your own!
At or near each knooppunt, there’s a map showing the local area with connecting paths and points, so you can navigate without needing GPS. In the picture above, the route we took is marked with green lines, and the dark blue lines show the other bicycle routes in the area. In purple between points 44 and 48, I marked the part where we deviated from the nice paths and went on the normal bike path alongside the road. As mentioned above, we started at the train station in Sassenheim, and just went towards the town center until we hit Hoofdstraat, then turned right. That pretty much put us at point 50 (bottom center, marked with a big star).
The route in text: Sassenheim Station > 50 > 58 > 55 > 57 > 38 > 07 > 49 > 40 > 48 > 11 > 44 > towards 06 then turn left at Delftweg to 48 > 47 > 80 > 75 > 74 > 59 > 58 > 56 > 50 > Sassenheim Station.
Cycling through tulip fields!
We improvised a bit (that’s the polite phrasing for “going the wrong way but being fine with it and eventually getting back on track”, right?), but generally stuck to the above route. Go at a comfortable pace, take photos, pull off for a picnic when you feel like it, and don’t forget to literally stop and smell the flowers! There are also a couple cafes throughout the route, and their prices looked reasonable.
There are other systems of numbered route points that you’ll see on wooden posts as you cycle around. You want to use the green circled numbers that are on small street signs.
Bring picnic snacks (cheese, crackers, fruit, etc.) and at least a liter of drinking water.
Dutch words that might be useful:
bloem(en) = flower(s)
bollenvelden = bulb fields, the more accurate name for the tulip fields (since there are daffodils and hyacinths as well)
fiets = bike, both the noun and the verb
tulp(en) = tulip(s)
Tulip fields without cycling
If cycling isn’t your forte, you can still see much of this route if you take the train from Haarlem to Leiden (about 20 minutes), though be warned that it flashes by pretty quickly. You can also walk through displays of countless varieties of tulips and other bulb flowers at the Keukenhof gardens.
Is seeing the Dutch tulip fields on your bucket list? If you’ve already been, what’s your favourite route?
If you’re mentoring undergrads (or are an undergrad yourself) who particularly like coding, this could be great astro-programming experience for them! Google Summer of Code is a paid internship for people who are enrolled as undergraduate students as of May 4th 2017.
Please encourage your undergrads to apply!! Applications are open until April 3rd. Check out the main GSoC website for more info.
Hack Together Day is a day to work intensively on projects, individually or in small groups, of interest to the astronomical community. A wide variety of projects will be undertaken, spanning everything from software development to community outreach to scientific research to trying out new analysis tools. We’ll also ask the contributors for SS16 (Developments and Practices in Astronomy Research Software) block 3 to be at the hack day, to help participants install, configure, and use the featured software packages. This information will be shared here once the talk schedule is confirmed.
Hack day or programming experience is not required; newcomers are extremely welcome! Project ideas and participants will be solicited before and during the meeting. Participants can lead or join a project, and should plan on focusing on only one thing.
Hack Together Day will take place on Thursday June 29th from 9:00 to 17:30, with the usual breaks for the plenary session, coffee and lunch.