Dark matter, the more broody and mysterious cousin of matter, is coming to SciBar this month. Unlike regular matter, dark matter has defied precise definition for years. We know it exists due to its gravitational influence on objects in space, we just don’t know exactly what it is. Curious researchers have relentlessly pursued it for answers across the universe in a game of cosmological cat and mouse. Dark matter has challenged our current understanding of the universe we live in, and scientists are bringing us ever closer to one of nature’s most elusive offspring.

The theory of dark matter has gradually taken form over the last century, and gained significant momentum in the 1930s and the 1970s when fresh and compelling evidence was unearthed. Fritz Zwicky’s 1933 investigation into the mass of galaxies compared to the light they emitted concluded that “dark matter is present with much a greater density than luminous matter” (1).

dark matter
The dark matter halo surrounding a spiral galaxy (4)

Then over 30 years later Vera Rubin found that the observed and expected behaviour of stars in rotating galaxies were at odds with each other (2). They were measured moving faster than they ought to under the gravitational influence the other visible stars in the galaxy, implying the existence of a “dark halo” of matter pulling them along (3). Dark matter has a plethora of astrophysical phenomena attributed to its presence, including a starring role in the gravitational lensing of light (the topic of a previous SciBar).

Various candidates for dark matter have made headlines in recent years (5,6), and with new experiments being devised and improvements made to existing ones, it looks like dark matter is running out of corners to hide in. The investigation has determined where in the universe it can be located, how it behaves, and the range of masses it could occupy (7), and yet dark matter is still clinging tightly to its identity. There are possible dark matter candidates that exist both within and without the standard model of physics, in baryonic matter (the stuff we’re made of) and in non-baryonic (8). One the most promising candidates is what is known as a Weakly Interacting Massive Particle (or WIMP for short) (9). Dr. Chamkaur Ghag is a field-leading researcher hunting for WIMP interactions. He has worked on the most sensitive detection experiments in the world and is designing the next generation of facilities to tease out the truth of dark matter (9).

Despite the competition with alternative theories for its place in (or out) of the spotlight, dark matter has remained a crowd favourite. Its reluctance to behave in a familiar way has sparked the curiosity of physicists the world over, and its identification will give us even greater insight into both the past and future evolution of the universe (10).

So join us and Dr. Chamkaur Ghag at The Star of Kings (126 York Way, N1 0AX), 7pm 13th June 2018, and step into the dark.

For more information visit our event page

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References

  1. The Early History of Dark Matter – Sidney Van Den Bergh – Publications of the Astronomical Society of the Pacific, Vol. 111, No. 760 – page 657 – June 1999
  2. Rotation of the Andromeda Nebula from a Spectroscopic Survey of Emission Regions – The Astrophysical Journal. 159 – page 379–403 – February 1970
  3. Review of particle physics, Physical Review D – Particles, Fields, Gravitation and Cosmology – Page 289 – July 2012
  4. http://people.virginia.edu/~dmw8f/astr5630/Topic05/t5_halo_sketch1.jpg – Graduate Extragalactic Astronomy – Professor Mark Whittle, University of Virginia
  5. https://www.bbc.co.uk/news/science-environment-44370751
  6. https://phys.org/news/2018-03-unprecedentedly-wide-sharp-dark.html
  7. Scalar dark matter candidates – C. Bœhm, P. Fayet – Nuclear Physics B 683 – Page 219 – Jan 2004
  8. Dark Matter Candidates from Particle Physics and Methods of Detection – Jonathan L. Feng – Ann. Rev. Astron. Astrophys – 48: 495, Page 7 – 2010
  9. http://www.ucl.ac.uk/physics-astronomy/people/academic-staff-profiles/chamkaur-ghag – Dr. Chamkaur Ghag
  10. Dark Matter Candidates from Particle Physics and Methods of Detection – Jonathan L. Feng – Annual Review of Astrononomy and Astrophysics 48: 495, Page 3 – 2010

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