Monday, April 1, 2013

The universe as seen by Planck (conference)

The 47th ESLAB symposium. All the cool kids will either be there, or watching it live on the webcast. Are you one of the cool kids?

This week I will be at a scientific conference, organised by ESA. In ESA's words, this conference is "An international conference dedicated to an in-depth look at the initial scientific results from the Planck mission". The conference is taking place in the small Dutch down of Noordwijk. At this conference there will be many people from within the Planck collaboration, who I'm sure will be delighted to finally be able to talk about their work and many people like myself who have spent the last few years eagerly anticipating the Planck collaboration's results.

The conference will have a live webcast here, you should watch some of it.

I will also be blogging during the conference. My goal is to try to write a new post here each day summarising the most interesting talks and discussions from the conference that day.

Why am I doing this?

An absolutely wonderful image showing how the various all sky images of the CMB anisotropies have improved each decade.

This won't be an easy task. The conference goes quite late each day and many topics will be covered, but I want to do this anyway. To understand why, first go watch my new favourite video on the internet. Brady Haran makes science videos and if you've never seen them, you should go check them out. I felt like Brady was taking the words out of my mind when I saw that video. One day the utopia that Brady and I envisage will exist and a Planck conference like this will be besieged by legions of fans. One auditorium will be fill of fans of non-Gaussianity and fans of Gaussianity, on opposite side, cheering their preference on. Another auditorium will be filled with fans of dark radiation, cheering their team on. Yet another will be filled with fans of the cosmological constant shouting their favourite chants at their mortal enemies, the quintessence crowd. But that day is not today.

This week the talks will be aimed at cosmologists, astronomers and astrophysicists and the public will have to put up with bloggers like me who try their best to make the talks intelligible to the interested member of the public.

But that's not my only motivation. I also want to learn things myself. Conferences like this are tiring. Trying to take in information over the full week is difficult. By forcing myself to try to write something every day about the conference I will also force myself to pay more attention during the week.

Most importantly, I hope that if I write something here that is wrong, or is some sort of misconception on my behalf, that somebody reading will call me out on it (so please do, for my sake and for the sake of the other readers). Similarly, if I don't understand something during a talk I will write down questions here. If you know the answer, please let us know. Also, whether you're a cosmologist, or member of the public, if you've got a question about the conference, please ask. Either I can answer you, another reader can answer you, or I can ask someone at the conference and get an answer for you that way.

What will I post about?

There will be many talks each day on a variety of topics. I would not be able to summarise every talk, even if I wanted to. So, I won't. What I will do is write about a selection of events and talks from the day that satisfy any the following criteria:

  • I found it interesting (this is my blog, so fair is fair)
  • It generated a lot of conversation and/or controversy at the conference
  • Things that I think might have human interest value
  • And... finally, the things that I think will be interesting to readers and other physicists, even if I'm not so interested myself.

I can't cover everything, so if you were at the conference and you stumble across this blog and I didn't write about your talk, I'm sorry. I promise that if people interact with me through the comments and/or Twitter, the chances that I will cover what they talk about will astronomically increase.

Highlights to expect

The conference hasn't started, but we've all seen the papers, and the conference programme can be found here. There may be surprises and unexpected controversies, but here's a few things to look out for during the week (from my perspective):

Andrei Linde. Proof that cosmology can make you rich (if Mr Milner chooses to give you $3,000,000). But is inflation correct? And has Planck made it more believable, or less testable, or both?

  • What is the community's perspective on inflation models post-Planck? Andrei Linde and Slava Mukhanov will both be at the conference and are members of the founding gang of the theory of inflation, which is the leading candidate for how the primordial density perturbations in the universe were generated. There are better models of inflation and there are worse models of inflation. Arguably, what Planck saw is more in line with what the more believable models of inflation predict. It will be interesting to see what the conference's consensus is on inflation and what these two very vocal Russian physicist's perspective will be. Is it now 100% verified (I wouldn't support this)? Has it been given a boost in believability (probably)? Does the lack of observation of new effects in the primordial universe starve us of insight into the nature of inflation (I expect some will argue this)? We will see...
  • Planck detected fewer galaxy clusters than it was expected to. It detects these cluster from the way they affect the CMB as it passes through them. One possibility is that their are fewer galaxy clusters, which would be a consequences of neutrinos having relatively large masses. Another possibility is just that Planck is under-estimating the masses of these clusters. I'm curious to see conversations develop around this issue.
  • There is tension between the results from Planck and local measurements of the expansion rate of the universe. Have these local measurements just made a mistake, or is this a sign of interesting local, or late-universe physics? Similarly, the South Pole Telescope seems to have results that are slightly discrepant with Planck. Have SPT made a mistake, or is the sky anisotropic and SPT have seen a genuine effect?

  • How have the more ambitious theorists reacted to Planck's abundance of null results? Verifying that cosmology requires no new epicycles was a triumph for cosmology and humanity's pursuit of knowledge, but where will theorists turn to now? There are still unanswered questions in cosmology, even if no new clues as to how to resolve them. Moreover, just because we haven't yet observed deviations in the early universe, doesn't mean there aren't more subtle deviations still waiting to be found.

  • The keynote talks. On Tuesday and Wednesday there will be keynote talks at 17:00 CET and on Friday at 14:00 CET. Whether you are a scientist or not, these talks would be well worth tuning into the webcast to listen to. They will be more general and more speculative than the rest of the talks. On Wednesday there will also be a public session immediately following the keynote talk and on Friday, the conference summaries will follow the keynote talk. So you should also tune into the webcast to watch them.

I ask for your forgiveness in advance

Each of the posts I manage to write this week will be written under immense time pressure. The conference ends each day at about 6-7pm and starts the following morning at 9am. I also have to eat. I won't have time to carefully read over anything I post, nor to thoroughly check the physics. I'll do my best.

This is also the first time I've attempted anything like this. Hopefully I'll learn and do it better next time. Any feedback, advice or suggestions would be more than welcome.

Because of the above, I should add the usual disclaimer that any views expressed by me over the next four days certainly don't reflect the views of the conference organisers, nor my employers. But I'll add an additional disclaimer too. The views expressed over the next four days will possibly not even reflect what my own views would be upon reflection.

I might have a go at live-blogging, if I get adventurous later in the week. Or, I might tire myself out and skip a day. We will have to wait and see.

I will do my best to Tweet a bit and follow Twitter during each day. You can follow me at @just_shaun and the obvious hasthag to follow is #Planck. that is the one I will try to follow.


Noordwijk. Does anyone else think that ESA should have released Planck's results in June?  I'm still tempted to go for a swim on Friday.

This week ESA is hosting a conference in Noordwijk, in The Netherlands to analyse and discuss the cosmological results from the Planck satellite. I will be here and will try to write daily summary posts about the most interesting talks and discussions from the day. You can follow the conference through its webcast, which is presented live here. You should pay particular attention to the keynote talks each day, which are at 17:00 (CET) on Tuesday and Wednesday and 12:00 on Friday, as well as the public session following the keynote talk on Wednesday and the conference summary following the keynote talk on Friday.

Please ask questions in the comments during the week if you want me to clarify anything (whether you're an expert or not). If you think I've written something that is wrong, please point this out in the comments. Half of the reason I am doing this is to learn myself and if I have any misconceptions I really want them to be pointed out. Also, if you know the answer to any questions I happen to ask, please provide them in the comments. If you want me to cover anything specific, please point this out in the comments.

This won't be easy so any encouragement and/or sharing of these posts that you wish to do/give will be most welcome!

[The first day's summary is now here]

Twitter: @just_shaun


  1. I'm looking forward to reading your reports from the conference. Hopefully writing about it will help you rather than wear you out. Enjoy the conference!

    1. Thanks for this initial comment of encouragement, Sedeer. It was much appreciated.

  2. Shaun,
    You are doing a great favor to persons who couldn't attend that conference. Keep the good work.