Syksy Räsänen

University researcher in theoretical physics at the
University of Helsinki, Department of Physics,
Division of Particle Physics and Astrophysics

Leader of the theory project
"Cosmology of the early and late universe" at the

Helsinki Institute of Physics

Teoreettisen fysiikan dosentti Helsingin yliopistolla,
yliopistotutkija hiukkasfysiikan ja astrofysiikan osastolla,
adjungoitu tutkija Fysiikan tutkimuslaitoksella

University of Helsinki
Department of Physics
P.O. Box 64 (Gustaf Hällströmin katu 2a)
FIN-00014 University of Helsinki

Tel +358 (0)2 941 51012
Fax +358 (0)2 941 50610

Email syksy dot rasanen at helsinki dot fi

Research interests
  • My main research topics at the moment are the effect of cosmological structure formation on the expansion of the universe and on light propagation, and Higgs inflation. I am interested in the backreaction conjecture, according to which structure formation would lead to the observed larger expansion rate and longer distances without the need for dark energy or modified gravity. Other research topics past and present include the cosmic microwave background, dark energy, magnetogenesis, tests of homogeneity and isotropy, string gas cosmology and the ekpyrotic scenario. I am a member of the Euclid consortium.

  • In addition to my PhD students Juha-Matti Ojanperä, Eemeli Tomberg and Pyry Wahlman, my current collaborators include Shaun Hotchkiss at the University of Auckland, Vera-Maria Enckell, Kari Enqvist and Francesco Montanari at the University of Helsinki, Miklas Långvik and Elisabetta Majerotto at Universidad Autónoma de Madrid.

  • Popular articles about backreaction include these from Scientific American, New Scientist, and (most recently) New Scientist. For an introduction for physicists, see this review or this review. A CGQ+ Insight piece on the backreaction debate is here.
CV, publications and talks
  • My popular talks, essays, articles and so on are announced on my Twitter account.

  • I write a popular blog on particle physics and cosmology called Kosmokseen kirjoitettua for the astronomical society URSA. (I used to write the blog Maailmankaikkeutta etsimässä for the Magazine Tiede until quitting at the end of May 2013.) (In Finnish.)

  • From 2014 to 2015, I wrote a monthly science column for the newspaper Helsingin Sanomat. (In Finnish.)

  • An article about facts and action in science and politics in the Helsinki area teachers' trade union magazine Rihveli (pages 6-9). (In Finnish.)

  • My column about cosmology, literature and mythology was published in the University of Helsinki comparative literature students' magazine Teema 1/2017. (In Finnish.)

  • A defense of the theory of everything in the magazine Tieteessä tapahtuu. (In Finnish.)

  • An article about teaching physics and the meaning of physics in the Helsinki area teachers' trade union magazine Rihveli (pages 6-7). (In Finnish.)

  • A republication of my assessment of the University of Helsinki's Visio400 process in a collection of critical writings on the University of Helsinki. (In Finnish.)

  • An overview of 100 years of general relativity in the science teachers' association MAOL's magazine Dimensio (In Finnish.)

  • An article about the responsibility of scientists, "Tiedettä apartheidin aikaan", in the magazine Tiedepolitiikka. (In Finnish.)

  • A critical assessment of the University of Helsinki's Visio400 process and leadership in the magazine Image. (In Finnish.)

  • A review of Nate Silver's book "The Signal and the Noise" in the magazine Tieteessä tapahtuu. (In Finnish.)

  • A press release about our paper on testing cosmic homogeneity and isotropy. (In Finnish.)

  • An article about predictions in science in the magazine Tieteessä tapahtuu. (In Finnish.)

  • An article about dark matter, dark energy and cosmology in the magazine Skeptikko 1/2015. (In Finnish.)

  • An article about predictions in economics and the responsibility of scientists in the magazine Tieteessä tapahtuu. (In Finnish.)

  • A review of an introductory text on special relativity. (In Finnish.)

  • A speech on Hiroshima day in 2014. (In Finnish.)

  • An essay about utopia published in the magazine Hybris. (In Finnish.)

  • An article co-written with Kari Enqvist on the curious phenomenon of relativity denialism in the magazine Tieteessä tapahtuu. (In Finnish.)

  • In 2014, I was awarded the J.V. Snellman prize for communicating science to the public by the University of Helsinki. My acceptance speech is here. (In Finnish.)

  • In 2013, I co-scripted a circus show about the history of the universe.

  • A recent talk on publishing in particle physics and cosmology at an event about the future of Finnish university research and teaching, organised by the Ministry of Education and Culture and the Academy of Finland. (In Finnish.)

  • A comment on some misconceptions regarding general relativity and quantum physics in the magazine Tieteessä tapahtuu. (In Finnish.)

  • An interview about open access and the boycott of the corporate publisher Elsevier in the May 2012 issue of Yliopistolainen. (In Finnish on page 10, in English on page 24.)

  • An article on Einstein as a dissident of physics and politics in the magazine Tieteessä tapahtuu. (In Finnish.)

  • I often give public talks. One of my favourites in recent years was this one on dark energy at Arkadia International Bookshop. (In English.)

    Video recordings of talks include one at Studia Generalia about dark matter, at Vox about doing physics (my piece starts at 42.50) and at Tiedeviikko about my own research. (In Finnish.)

  • Recordings of interviews include a light-hearted half an hour at Radio Rock's Heikelä Korporaatio, touching on matters such as the big bang, free will, roleplaying games and time travel. I was also interviewed on Heikelä Korporaatio about the search for the Higgs particle (starting at 14.57). There's also a later interview about matters such as the Higgs particle, Schrödinger's cat and the occupation of Palestine. (In Finnish.)

  • I was a member of HS-raati, a group of Finns whom the newspaper Helsingin Sanomat asked for opinions on topical matters. My answers on issues such as the "war on terror", the Occupy movement, the legacy of Steve Jobs, the presidency of Tarja Halonen, intervention in Syria, president Niinistö's working group on social exclusion, the Muhammad video and Pekka Himanen's sustainable development report can be found on the HS website. (In Finnish.)