or the
French version
|
Cosmology and art |
New on the tutorial:
Cosmology is the study of the origin, current state, and future of our Universe. This field has been revolutionized by many discoveries made during the past century. My cosmology tutorial is an attempt to summarize these discoveries. It will be "under construction" for the foreseeable future as new discoveries are made. I will attempt to keep these pages up-to-date as a resource for the cosmology courses I teach at UCLA. The tutorial is completely non-commercial, but tax deductible donations to UCLA are always welcome.
Astronomy and cosmology are very much mathematical sciences, but I have attempted to avoid higher math in these pages. I do use high school algebra and geometry - courses required for admission to UCLA - but I have also included some animations [1, 2, 3, 4, 5, 6, 7], some Java applets [1, 2], and many illustrations in the tutorials, the ABC's of Distances, and the answers to some of the Frequently Asked Questions.
In addition to the cosmology tutorial, there is also a relativity tutorial and extensive discussions on the age, density and size of the Universe. There is also a bibliography of books at a range of levels, and a Javascript calculator of the many distances involved in cosmology.
Slides for recent talks:
The course notes (130 pages, 398 equations, 51 figures) for the upper division undergraduate Stellar Systems and Cosmology course, Astronomy 140, that I last taught in spring 2008 are available on the Web. And for a much more technical discussion of cosmology see my graduate course Astro 275 lecture notes (126 pages, 381 equations, 42 figures). This course was last taught in the spring of 2009. If this course Web site gets closed, you can use a backup copy of the A275 notes.
13 Jan 2012 - The BBC reports that the dilution refrigerator that cools the High Frequency Instrument on the European CMB satellite Planck to 0.1 K has run out of 3He. The Low Frequency Instrument continues to operate at 4 K. The first announcement of cosmological results from Planck is scheduled for Jan 2013.
04 Oct 2011 -
Saul Perlmutter, Adam Riess & Brian Schmidt have won the
2011 Nobel Prize in Physics
for their work showing the Universe is accelerating
by measuring the brightness of distant supernovae.
This is evidence for an energy density of the vacuum or a
cosmological constant.
22 Sep 2011 - Here's the paper. But I agree with this reaction: probably not. This experiment did not show that neutrinos arrived 60 nsec earlier than photons, because they could not send photons through the 730 km of rock traversed by the neutrinos. Instead the neutrinos arrive earlier than a prediction coming from a long multi-step calculation. This may become another DAMA imbroglio. Could it be something in the L'Aquila air or water?
Update: 18 Nov 2011 - Nature reports that the OPERA group have repeated their measurement with a new twist. They had previously used a 10,000 ns long pulse of protons to make the neutrinos, but because the pulse had sharp leading and trailing edges and they detected such a large number of neutrinos (over 10,000) they had a good statistical result. The new twist was to use a very short pulse of protons (10 ns long) so they can measure the time of flight accurately with a modest number of neutrino detections (20 in this case). They get the same timing results. This new experiment is included in v2 of the preprint. But they are still using the same clocks so any systematic errors will be the same.
Update 16 Mar 2012 - ICARUS, another detector in the Gran Sasso lab, checked their neutrino times and see them arriving at just the predicted time. This does not confirm the OPERA result.
12 Aug 2011 - There has been a spate of news reports about a paper by Feeney etal. But this paper just gets an upper limit, and concludes "the WMAP 7-year data do not warrant augmenting LCDM with bubble collisions". So this is a test of one model of the multiverse but the test came back negative.
15 Jul 2011 - Turyshev et al. (2011, PRL accepted) have recovered and analyzed old tracking files on Pioneer 10 and 11, more than doubling the time span of the available data. They find that the anomalous acceleration is decaying with time in a manner consistent with the anisotropic waste heat emission model.
30 Jun 2011 -
Morlock et al. report on a
quasar with
redshift z = 7.085 found in
an infrared survey.
The spectrum has several lines so this a secure redshift.
The arXiv preprint
appeared on July 4. Note that Nature does allow posting of preprints
prior to publication, although these authors did not do so.
01 Jun 2011 - Marc Davis, George Efstathiou, Carlos Frenk and Simon
White have won the
Gruber Prize in Cosmology for their early work
simulating Universes dominated by
cold dark matter.
25 May 2011 - while chairing a session at the AAS meeting yesterday
one the of speakers gave a well founded photometric
redshift of
z = 9.4
for GRB 090429B.
Press conference today and
paper on the arXiv submitted.
News reports:
USA Today,
BBC,
Bad Astronomy
25 May 2011 - Warren Brown has found a detached binary with two white
dwarf stars orbiting with a 12.75 minute period and a velocity
amplitude of 1300 km/sec. This system will merge due to gravitational
wave radiation in 0.9 Myr. Update 12-Jul-2011: the
preprint is out.
17 May 2011 - Blake
et al. (2011, MNRAS accepted) report on the results of
WiggleZ,
which has measured the redshifts of more than 200,000 galaxies
and measured the baryon acoustic scale at a
redshift of
z = 0.6, or 5.7 billion years
before now. The measured value of the acoustic scale
agrees quite well with the standard ΛCDM model
and indicates that the dark energy is behaving like a cosmological
constant.
11 Apr 2011 -
Conley et al.
have released a catalog of 472 supernovae so I have updated
my supernova cosmology page.
The new dataset is quite consistent with previous supernova datasets.
16 Mar 2011 -
Riess et al.
(2011, ApJ, 730, 119) report Ho = 73.8 ± 2.5
km/sec/Mpc.
27 Jan 2011 -
Bouwens et al.
have gotten a lot of press due to a
NASA press release about their candidate
z=10 galaxy.
While there is nothing wrong with this paper --
a z=10 galaxy would look just like this candidate --
the evidence presented is rather weak. The
Hubble Space Telescope saw this
object at 1.6 μm wavelength, but not at any shorter wavelengths.
This could be due the
Lyman α Forest
absorbing all the light at wavelengths shorter than (1+z)*0.122 μm
= 1.34 μm. It is important to confirm that this object emits at
all wavelengths longer than 1.34 μm but the HST is unable to do this
due to a design error when it was made: the mirrors are heated to room
temperature. As a result the HST is not sensitive to wavelengths
longer than 1.6 μm.
The JWST will not
repeat this error. The
Spitzer Space Telescope is not sensitive enough to detect this
galaxy.
11 Jan 2011 -
Planck has released its
Early Release Compact Source Catalog
and also catalogs of
compact cold cores
n Milky Way molecular clouds
and galaxy clusters
found via the
Sunyaev-Zeldovich effect.
These results are designed to not include any CMB
information but they are very interesting nonetheless.
28 Nov 2010 - There has been a
lot of
discussion about a preprint by
Gurzadyan & Penrose
entitled "Concentric circles in WMAP data may provide evidence of violent
pre-Big-Bang activity". I find this very unlikely, and
Peter Coles
also has
his doubts.
It is important to remember that this is a
Gurzadyan paper, and not a Penrose paper.
Update 6-Dec-2010: Moss, Scott
& Zibin and
Wehus & Eriksen both show that Gurzadyan & Penrose made
an error, and that simulated maps using the standard ΛCDM
model are fully consistent with the actual WMAP data.
15 Nov 2010 - Word came that
Allan Sandage
has died. He worked under Hubble as a student. He continued Hubble's work
in determining the Hubble constant by measuring the
distance and
redshift
of galaxies. He corrected the Hubble constant from the 500-600 km/sec/Mpc
value first found by Le Maitre and Hubble to about 50 km/sec/Mpc.
Sandage was then part of a controversy between the "50" camp and the
"100" camp led by de Vaucouleurs, which has ultimately been settled
in favor of the middle ground, with the best current value
of H0=70.4±1.4 km/sec/Mpc.
19 Aug 2010 - WMAP has completed its
end of mission calibration observations.
The thumbnail to the right is a map from Planck released in July 2010.
Click to get a larger version.
26 Jan 2010 - Geoff Burbidge, a cosmologist famous for working out how all the
elements heavier than helium are made in stars, and noted Big Bang skeptic, died
today in La Jolla. The high point of his career was the massive paper
B2FH,
"The Synthesis of the Elements in Stars".
The low point of his career was its end, devoted to promoting the
Quasi-Steady State Cosmology by
publications that verged on fraud.
Obituaries in the
LA Times, the
Wall Street Journal.
22 Jan 2010 - Andrew Lange, a principal in the
BOOMERanG experiment and
Planck, died today,
an apparent suicide.
He was very influential in pushing the development of extremely
sensitive
bolometer detectors in CMB experiments.
Update 27 Jan 2010:
New York Times obituary.
The legend that BOOMERanG showed the Universe is flat is actually not quite
correct, since the results published in 2000 had a serious
systematic error. The position of the peak
in the angular power spectrum of the
anisotropy of the CMB was known to
be ellpk = 210 ± 15 in 1999, and BOOMERanG found
ellpk = 197 ± 6 in 2000, while the correct value is
ellpk = 220. Thus while BOOMERanG provided improved precision,
it actually gave a less accurate value for the flatness of the Universe.
Since a flat Universe requires Ω=1, and Ω goes like
1/ellpk2, the 10% error in the BOOMERanG value
for ellpk really implied
a closed Universe. The
de Bernardis et al. paper correctly
claimed a flat Universe by using strong priors from non-CMB measurements.
Note that Andrew Lange also worked on the MAXIMA experiment which did not have
the systematic error, and the systematic error was corrected in 2001.
He always worked on the bleeding edge of the possible, and really extended
our capabilities in observational cosmology.
11 Nov 2009 - Fixsen
has combined velocity maps from the
WMAP satellite with the
CMB
spectra measured by the
instrument on the COBE
satellite
to come up with a quite precise value
for the To of the CMB.
FIRAS has measured the difference in total CMB power associated with
the dipole pattern to an accuracy of 1 part in 700, and since this
power varies like (v/c)To4, the well determined
velocity measured by WMAP gives a 1 part in 2000 determination of
To.
FAQ |
Tutorial :
Part 1 |
Part 2 |
Part 3 |
Part 4 |
Age |
Distances |
Bibliography |
Relativity
© 1996-2011 Edward
L. Wright. Last modified 18 Mar 2012Gruber Prize for DEFW
Gamma Ray Burst Distance Record
Binary Star with a 12.75 Minute Period!
Major New BAO Data Set
Updated and Expanded Supernova Data Set
New Hubble Constant
z=10 Galaxy?
Planck Early Results
Cosmic Circles[?] = Cosmic Rebirth[?]
Allan Sandage: 1926-2010
WMAP: It's a wrap
WMAP Retires
10 Aug 2010 - WMAP has stopped taking
cosmology data after nine full years of observations, with
one extra day to finish the last season of Jupiter observations.
There will be
a few days of calibration data taken at different precession angles
and then WMAP will be done.
However, observations of the CMB will continue with the Planck mission
which has more frequencies, better sensitivity, and better angular
resolution than WMAP.
Geoff Burbidge, 1925-2010
Seven Year WMAP Results
25 Jan 2010 - The seven year datasets and papers from
WMAP
are posted on LAMBDA.
Luckily for me, the default parameters in my
Cosmology Calculator taken from the
first year results are still a good fit to all the data.
The image on the right shows a map of the
anisotropy of the Cosmic Microwave Background
in the three highest frequency bands measured by WMAP: 41, 61 and 94 GHz.
Click on the thumbnail for a larger version.
A Sad Loss
New determination of TCMB
News of the Universe Archive
Other Good Links