About me

About me

• Associate Professor in Physics
  and Academy Research Fellow
• In Helsinki (more or less) since my PhD (2011)
• Originally from Scotland 🏴󠁧󠁢󠁳󠁣󠁴󠁿
• Work on gravitational waves in the early universe
  + processes which make them

But before I tell you about my research,
I want to take you back to 2003...

Education

Studies

• I had no course choice until my 3rd year
  ⇒ very broad, valuable, base of science knowledge
• Later, when I could, I focussed on theoretical topics:
  • Quantum optics
  • Particle physics
  • Quantum field theory
• Took history of science and other topics non-credit
  - and nearly started a PhD in history of science
• My Masters project (pro gradu) was on wetting
  - last minute change to theoretical particle physics

How I got into physics: summer jobs

• 2003: Condensed Matter, University of St. Andrews
• 2004: (bummed around, folk music concerts)
• 2005: Space Physics, Imperial College London
  working on the Cassini space probe 🛰😃
• 2006: Two summer jobs,
  1. Theoretical Physics, Imperial College London
     working on complex networks
  2. Applied Mathematics, Imperial College London
     studying mathematical modelling of evolution
• 2007: CERN OpenLab (computing department)
  working on volunteer computing/citizen science

Summer jobs, Masters, PhD ...

• Don't rush your studies
  Supervisors and employers care about you developing into a mature, independent scientist
• Finding projects: talk to potential supervisors + current students:
  • Is it a nice group to work in?
    (for 3 months? 1 year? 4 years?!)
  • Can you get a summer job?
  • What courses do they suggest?
  • Will someone mentor you?
• Do try new things and take unexpected turns.

Key takeaways:

• Listen to:
  • Potential employers
  • Senior students
  • Mentors
  • Supervisors
• Faster doesn't mean better. Don't rush your studies.
• Interests + connections you develop will matter.
• Be broad now, you can be narrow later
  ☞ Don't miss out on your new favourite thing.

About gravitational waves and cosmology

What is a gravitational wave?

- Stretches and squeezes a ring of matter

First evidence: Hulse-Taylor pulsar

Hulse-Taylor pulsar

• Two neutron stars, of which at least one pulsar
• Orbital diameter: 3 light seconds
• Orbital period: 7.75 hours
• Orbit slowly contracting (3.5 metres per year)
• Energy must be going somewhere...
  gravitational waves
• Gravitational wave power output: $7\times 10^{24} \, \mathrm{W}$
  (about 2% of the Sun's EM radiation).

LIGO at the Hanford Site

Two neutron stars merging

Neutron star merger and cosmology

1. Photons arrived 1.7s later, after travelling 100 M ly
   ⇒ gravitational waves travel at the speed of light
2. Independent measurement of universe's expansion:
   • Luminosity of gravitational waves → distance
   • Telescopes observe host galaxy → velocity