The interplay between cosmological expansion and massive objects

Add to your list(s) Download to your calendar using vCal

• Roshina Nandra (Cavendish Astrophysics)
• Tuesday 24 May 2011, 16:30-17:00
• Martin Ryle Seminar Room, Kavli Building.

If you have a question about this talk, please contact Sally Hales.

It has been observed that there are definite cut-offs at which the radial velocities of particles near galaxies/clusters are exactly zero. This boundary can be interpreted as the edge of the galaxy/cluster, where the gravitational attraction of the central object is exactly balanced by the cosmological pull due to the universe’s expansion. One may begin to explain this phenomenon using a non-zero cosmological constant, but of course the current universe is not purely de-Sitter. In this talk I will present a new theoretical framework for describing a mass particle in a realistically expanding background. I will show how this leads to a fully general relativistic invariant expression for the radial force required to hold a test particle at rest relative to the central mass, and use it to successfully predict the edges of large-scale objects and also the locations of maximum stable orbits. Finally I will present some extensions of this work, which include the implications for a universe whose expansion is driven by phantom energy, which leads to a “Big Rip” at a finite time in the future, and the solutions for spatially curved cosmologies.

This talk is part of the Cavendish Astrophysics Seminars series.

This talk is included in these lists:

• All Cavendish Laboratory Seminars
• All Talks (aka the CURE list)
• CamTalks
• Cavendish Astrophysics Seminars
• Cavendish Astrophysics Summary
• Centre for Health Leadership and Enterprise
• Combined External Astrophysics Talks DAMTP
• Cosmology lists
• Cosmology, Astrophysics and General Relativity
• Featured lists
• Kavli Institute for Cosmology Talk Lists
• ME Seminar
• Martin Ryle Seminar Room, Kavli Building
• Neurons, Fake News, DNA and your iPhone: The Mathematics of Information
• Priscilla
• School of Physical Sciences
• Thin Film Magnetic Talks

Note that ex-directory lists are not shown.