Download Revealing the nature of dark energy

Seeing the Invisible:
Observing the Dark Side of the Universe
Sarah Bridle
University College London
What we see
What we don’t see
What we don’t see
Missing matter: Dark Matter
(matter that doesn’t shine)
What we don’t see
Missing energy: Dark Energy
(energy that is not matter)
Missing matter: Dark Matter
(matter that doesn’t shine)
Supernovae as Standard Candles
Big Bang
5 billion years ago
Today
Why is the Universe Accelerating?
• Einstein’s cosmological constant
• A new fluid called Dark Energy
• General Relativity is wrong
Seeing the Invisible:
Is there something in between us and
the wall and tree?
Using the bending of light to see the
invisible
Just one Equation from
General Relativity
90 years ago
Eddington confirmed
Einstein’s prediction
during a solar eclipse
Average galaxies together to measure weak
gravitational shear
Simulated Dark Matter Map
Gravitational Lensing Map
Universe was 0.2 Gyr old
Universe was 1 Gyr old
Universe was 4.7 Gyrs old
Today (13.6 Gyr)
Map in 3d
Map in 3d
Typical galaxy
used for lensing
Typical star used for
finding telescope
response
Gravitational Lensing
Atmosphere and Telescope
Pixelisation
Noise
www.great08challenge.info
Results from the HST
COSMOS Survey
The Largest ever Survey with HST
The Visible
The Invisible
In 3 Dimensions
The Future
JDEM
FutureEnergy
prospectsSurvey
The Dark
• Cosmic microwave background radiation
– Distribution of dark matter at early times
• Distribution of galaxies
– Some clues to distribution of matter
• Galaxy velocities
– Galaxies fall towards dark matter clumps
• Gravitational lensing
CCD
Readout
Mechanical Interface of DECam
Project to the Blanco
Focal plane (detector)
Filters
Shutter
Hexapod
Corrector
Lenses
Ground vs Space
space
weak lensing shear
ground
HST COSMOS
Why is the Universe Accelerating?
• Einstein’s cosmological constant
• A new fluid called Dark Energy
• General Relativity is wrong