Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New survey hints at exotic origin for the Cold Spot

26.04.2017

A supervoid is unlikely to explain a 'Cold Spot' in the cosmic microwave background, according to the results of a new survey, leaving room for exotic explanations like a collision between universes. The researchers, led by postgraduate student Ruari Mackenzie and Professor Tom Shanks in Durham University's Centre for Extragalactic Astronomy, publish their results in Monthly Notices of the Royal Astronomical Society.

The cosmic microwave background (CMB), a relic of the Big Bang, covers the whole sky. At a temperature of 2.73 degrees above absolute zero (or -270.43 degrees Celsius), the CMB has some anomalies, including the Cold Spot. This feature, about 0.00015 degrees colder than its surroundings, was previously claimed to be caused by a huge void, billions of light years across, containing relatively few galaxies.


Figure 1. The map of the cosmic microwave background (CMB) sky produced by the Planck satellite. Red represents slightly warmer regions, and blue slightly cooler regions. The Cold Spot is shown in the inset, with coordinates on the x- and y-axes, and the temperature difference in millionths of a degree in the scale at the bottom.

Credit: ESA and Durham University


Figure 2. The 3-D galaxy distribution in the foreground of the CMB Cold Spot, where each point is a cluster of galaxies. The galaxy distribution in the Cold Spot (black points, at right) is compared to the same in an area with no background Cold Spot (red points, at left). The number and size of low galaxy density regions in both areas are similar, making it hard to explain the existence of the CMB Cold Spot by the presence of 'voids'.

Credit: Durham University

The accelerating expansion of the universe causes voids to leave subtle redshifts on light as it passes through via the integrated Sachs-Wolfe effect. In the case of the CMB this is observed as cold imprints. It was proposed that a very large foreground void could, in part, imprint the CMB Cold Spot which has been a source of tension in models of standard cosmology.

Previously, most searches for a supervoid connected with the Cold Spot have estimated distances to galaxies using their colours. With the expansion of the universe more distant galaxies have their light shifted to longer wavelengths, an effect known as a cosmological redshift.

The more distant the galaxy is, the higher its observed redshift. By measuring the colours of galaxies, their redshifts, and thus their distances, can be estimated. These measurements though have a high degree of uncertainty.

In their new work, the Durham team presented the results of a comprehensive survey of the redshifts of 7,000 galaxies, harvested 300 at a time using a spectrograph deployed on the Anglo-Australian Telescope. From this higher fidelity dataset, Mackenzie and Shanks see no evidence of a supervoid capable of explaining the Cold Spot within the standard theory.

The researchers instead found that the Cold Spot region, before now thought to be underpopulated with galaxies, is split into smaller voids, surrounded by clusters of galaxies. This 'soap bubble' structure is much like the rest of the universe, illustrated in Figure 2 by the visual similarity between the galaxy distributions in the Cold Spot area and a control field elsewhere.

Mackenzie commented: "The voids we have detected cannot explain the Cold Spot under standard cosmology. There is the possibility that some non-standard model could be proposed to link the two in the future but our data place powerful constraints on any attempt to do that."

If there really is no supervoid that can explain the Cold Spot, simulations of the standard model of the universe give odds of 1 in 50 that the Cold Spot arose by chance.

Shanks added: "This means we can't entirely rule out that the Spot is caused by an unlikely fluctuation explained by the standard model. But if that isn't the answer, then there are more exotic explanations.

'Perhaps the most exciting of these is that the Cold Spot was caused by a collision between our universe and another bubble universe. If further, more detailed, analysis of CMB data proves this to be the case then the Cold Spot might be taken as the first evidence for the multiverse - and billions of other universes may exist like our own."

For the moment, all that can be said is that the lack of a supervoid to explain the Cold Spot has tilted the balance towards these more unusual explanations, ideas that will need to be further tested by more detailed observations of the CMB.

###

Media contacts

Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7292 3979
Mob: +44 (0)7802 877 699
rm@ras.org.uk

Leighton Kitson
Durham University
Tel: +44 (0)191 334 6075
communications.team@durham.ac.uk

TV & radio facilities at Durham University

Durham University's academic experts are available for interview via down-the-line broadcast quality TV facilities from our Durham City campus, via broadcast provider Globelynx.

To request and check the availability of interviewees please contact the Durham University Marketing and Communications Office using the contact number above.

You can book the Globelynx fixed camera and circuit direct by logging into http://www.globelynx.com. The IFB number is +44 (0)191 384 2019.

If you have not booked a Globelynx feed before, or if you require any other support from Globelynx, please call +44 (0)20 7963 7174 (24 hours a day) for assistance.

A broadcast quality ISDN radio line is also available at Durham University and bookings can be arranged via the Marketing and Communications Office on the contact details above. The ISDN number is +44 (0)191 386 2749.

A landline number is available in our Media Suite which houses the television and radio facilities - +44 (0)191 334 6472.

Science contacts

Ruari Mackenzie
Department of Physics
Durham University
Tel: +44 (0)191 3343027
Mob: +44 (0)7858270502
ruari.mackenzie@durham.ac.uk

Professor Tom Shanks
Department of Physics
Durham University
Tel: +44 (0) 191 3343721
Mob: +44 (0)7590 848620
tom.shanks@durham.ac.uk

Images and captions

https://www.ras.org.uk/images/stories/press/Cosmology/CMB%20Cold%20Spot.jpg

Figure 1. The map of the cosmic microwave background (CMB) sky produced by the Planck satellite. Red represents slightly warmer regions, and blue slightly cooler regions. The Cold Spot is shown in the inset, with coordinates on the x- and y-axes, and the temperature difference in millionths of a degree in the scale at the bottom. Credit: ESA and Durham University.

https://www.ras.org.uk/images/stories/press/Cosmology/CMB%20Cold%20Spot%20survey.jpg

Figure 2. The 3-D galaxy distribution in the foreground of the CMB Cold Spot, where each point is a cluster of galaxies. The galaxy distribution in the Cold Spot (black points, at right) is compared to the same in an area with no background Cold Spot (red points, at left). The number and size of low galaxy density regions in both areas are similar, making it hard to explain the existence of the CMB Cold Spot by the presence of "voids". Credit: Durham University.

Images and captions are also available from http://astro.dur.ac.uk/~ts/coldspotpics.html

Further information

The paper on the "Evidence against a supervoid causing the CMB Cold Spot" by R. Mackenzie, T. Shanks, M.N. Bremer, Y-C Cai, M.L.P. Gunawardhana, A. Kovacs, P.R. Norberg and I. Szapudi, has just appeared in the journal Monthly Notices of the Royal Astronomical Society. The paper can be found at https://arxiv.org/abs/1704.03814

Notes for editors

Tom Shanks is Professor of Physics at Durham University. He has research interests in observational cosmology, galaxy and quasar surveys and galaxy formation.

Ruari Mackenzie is a final year PhD student at Durham University. His PhD is entitled "Surveying the Universe via Gas and Galaxies". His PhD is sponsored by the Science and Technology Funding Council.

Their team also includes other scientists from the Universities of Bristol, Durham and Edinburgh in the UK, the Barcelona Institute of Science and Technology in Spain, Pontificia Universidad Catolica in Chile and the University of Hawaii in the USA.

About Durham University

  • A world top 100 university with a global reputation and performance in research and education (QS and THE World University Rankings 2016/17 https://www.dur.ac.uk/about/rankings )

     

  • In the 2017 Times and Sunday Times Good University Guide, Durham was ranked fourth in the UK

     

  • A member of the Russell Group of leading research-intensive UK universities

     

  • Research at Durham shapes local, national and international agendas, and directly informs the teaching of our students

     

  • Ranked 39 globally for the employability of its students by blue-chip companies world-wide (QS World University Rankings 2016/17)

The Royal Astronomical Society

The Royal Astronomical Society (RAS: http://www.ras.org.uk), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organizes scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.

T: https://twitter.com/royalastrosoc

F: https://www.facebook.com/RoyalAstroSoc/

Dr Robert Massey | EurekAlert!

More articles from Physics and Astronomy:

nachricht Structured light and nanomaterials open new ways to tailor light at the nanoscale
23.04.2018 | Academy of Finland

nachricht On the shape of the 'petal' for the dissipation curve
23.04.2018 | Lobachevsky University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Structured light and nanomaterials open new ways to tailor light at the nanoscale

23.04.2018 | Physics and Astronomy

On the shape of the 'petal' for the dissipation curve

23.04.2018 | Physics and Astronomy

Clean and Efficient – Fraunhofer ISE Presents Hydrogen Technologies at the HANNOVER MESSE 2018

23.04.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>