astronautThe universe appears to be lopsided, and a new model that aims to explain this anomaly could offer a glimpse of what happened before the birth of it all.
A new model suggests this unevenness could be caused by an imprint left over from before the beginning of the universe, that is, before the cosmos ballooned almost instantaneously from less than the size of an atom to about golf-ball size. This process is called inflation.
Blowing up the balloon "Inflation theory does predict that we have these density and temperature fluctuations, but they should look the same everywhere across the sky," said Caltech astrophysicist Sean Carroll, who worked on the new model, detailed in the Dec. 16 issue of the journal Physical Review D. "But people who look at the data say they see one side of the universe has bigger fluctuations, and that's what we're trying to get a handle on."
Planetary double featureAn image from NASA's Cassini orbiter shows Saturn and its rings, with the planet Venus shining as a white speck just above and to the right of the image's center. The picture was captured by Cassini's wide-angle camera on Nov. 10, 2012, and released on March 4.
Cosmic baby picture
An all-sky image from the European
Space Agency's Planck spacecraft, released March 21, provides the most
detailed look yet at the imprint left behind by the big bang in the
cosmic microwave background. Patterns of temperature fluctuations,
shown in shades of red and blue, serve as a "baby picture" of the
universe when it was just 370,000 years old. The image suggests that the
universe is 100 million years older than scientists thought it was,
with more matter and less dark energy than they previously thought.
Big Bang in high fidelity
WASHINGTON: Big Bang remix! Scientists have devised an audio recreation of the Big Bang - in high fidelity - that started our universe nearly 14 billion years ago.
A decade ago, spurred by a question for a fifth-grade science project, University of Washington physicist John Cramer devised an audio recreation of the Big Bang.
Now, armed with more sophisticated data from a satellite mission observing the cosmic microwave background - a faint glow in the universe that acts as sort of a fossilized fingerprint of the Big Bang - Cramer produced new recordings that fill in higher frequencies to create a fuller and richer sound.
The sound files run from 20 seconds to a little longer than 8 minutes.
The effect is similar to what seismologists describe as a magnitude 9 earthquake causing the entire planet to actually ring. In this case, however, the ringing covered the entire universe - before it grew to such gargantuan proportions.
"Space-time itself is ringing when the universe is sufficiently small," Cramer said in university statement.
Cramer used data from the cosmic microwave background on temperature fluctuations in the very early universe.
The data on those wavelength changes were fed into a computer programme called Mathematica, which converted them to sound.
A 100-second recording represents the sound from about 380,000 years after the Big Bang until until about 760,000 years after the Big Bang.
"The original sound waves were not temperature variations, though, but were real sound waves propagating around the universe," Cramer said.
More complete data were recently gathered by an international collaboration using the European Space Agency's Planck satellite mission, which has detectors so sensitive that they can distinguish temperature variations of a few millionths of a degree in the cosmic microwave background.
That data were released in late March and led to the new recordings.
As the universe cooled and expanded, it stretched the wavelengths to create "more of a bass instrument," Cramer said. The sound gets lower as the wavelengths are stretched farther, and at first it gets louder but then gradually fades.
The sound was, in fact, so "bass" that he had to boost the frequency 100 septillion times just to get the recordings into a range where they can be heard by humans.
A decade ago, spurred by a question for a fifth-grade science project, University of Washington physicist John Cramer devised an audio recreation of the Big Bang.
Now, armed with more sophisticated data from a satellite mission observing the cosmic microwave background - a faint glow in the universe that acts as sort of a fossilized fingerprint of the Big Bang - Cramer produced new recordings that fill in higher frequencies to create a fuller and richer sound.
The sound files run from 20 seconds to a little longer than 8 minutes.
The effect is similar to what seismologists describe as a magnitude 9 earthquake causing the entire planet to actually ring. In this case, however, the ringing covered the entire universe - before it grew to such gargantuan proportions.
"Space-time itself is ringing when the universe is sufficiently small," Cramer said in university statement.
Cramer used data from the cosmic microwave background on temperature fluctuations in the very early universe.
The data on those wavelength changes were fed into a computer programme called Mathematica, which converted them to sound.
A 100-second recording represents the sound from about 380,000 years after the Big Bang until until about 760,000 years after the Big Bang.
"The original sound waves were not temperature variations, though, but were real sound waves propagating around the universe," Cramer said.
More complete data were recently gathered by an international collaboration using the European Space Agency's Planck satellite mission, which has detectors so sensitive that they can distinguish temperature variations of a few millionths of a degree in the cosmic microwave background.
That data were released in late March and led to the new recordings.
As the universe cooled and expanded, it stretched the wavelengths to create "more of a bass instrument," Cramer said. The sound gets lower as the wavelengths are stretched farther, and at first it gets louder but then gradually fades.
The sound was, in fact, so "bass" that he had to boost the frequency 100 septillion times just to get the recordings into a range where they can be heard by humans.
Big Bang Alternatives, anyone?
First clues to what came before the Big Bang
SYDNEY: The Big Bang is thought to have obliterated all trace of what came before. But astrophysicists now believe that interpreting an imprint from the earliest stages of the universe may provide some clues.
“It’s no longer completely crazy to ask what happened before the Big Bang,” said Marc Kamionkowski, of the California University of Technology in the USA.
Kamionkowski led a team who have proposed a mathematical model explaining an anomaly in what is supposed to be a universe of uniformly distributed radiation and matter. The study is detailed in the journal Physical Review D.
The Universe began not with a bang but with a low
moan, building into a roar that gave way to a deafening hiss. And those
sounds gave birth to the first stars.
Cosmologists do not usually think in
terms of sound, but this aural picture is a good way to think about the
Universe's beginnings, says......................
Big Bang Acoustics
Movie and Sound Files for Playing & Download
-
Left click hyperlink filename to play sound or movie.
Right click to copy file to your own computer.
Sound files are .wav and Movies are .mov (Quicktime) or .mpg (mpeg). Remember, small "laptop" speakers miss the deeper frequencies, so it is best to play the sounds over at least the larger type of computer speakers.
Simple/Small Selection
-
First, a small selection of the most important sound and movie files.
Evolving Sounds: the First 100 Million Years
s_1e6_lin_C.wav (313 kb sound) lilgli_1e6C.mov (1500 kb movie)
- The first million years. The sound files take the first million
years of cosmic sound and compress it into 10 seconds. The first
allows the loudness to vary (V) correctly (it increases with time), while the
second holds it constant (C). Two Quicktime movies show
slightly different versions of the changing sound spectrum, along with
the changing sound waveform and sky color. (from slide 107).
s_1e8_log_C.wav (376 kb sound) lglglg_1e8C.mov (1800 kb movie)
- The first 100 million years. These sound files take the first 100
million years of cosmic sound and compresses the time "exponentially" so
that the first 2 seconds span 100 to 1000 years; the next
two seconds span 1000 to 10,000 years; and so on, with 2
seconds for each factor of 10 increase in time, all the way up
to 100 million years (total of 14 seconds). The true volume increase
is too great to render correctly. Instead, the first version fakes an
increase to illustrate reality (Vfake), while the second keeps the volume
constant (C). Two Quicktime movies show slightly different
versions of the changing sound spectrum, along with the changing sound
waveform and sky color. (from slide 109).
Raw/Pure Sounds: Measuring the Universe
s_cofl_minute_44.m4a (524 kb) :
s_cofl_minute_44.wav (10.8 Mb) :
s_cofl_minute_5s.aif (10.8 Mb) :
-
The raw sound constructed from the observed angular power spectrum of
the microwave background. This is the fundamental observational basis
for Big Bang Acoustics. In practice, a number of distortions are present
in these raw sounds, which have been removed using a sophisticated
program (CMBFAST) for all but the next two sounds. (from slide 43).
-
The raw sounds from different types of Universe, calculated using CMBFAST.
The first plays the sound of three Universes of different density --
the densest Universe has the deepest voice, while the middle sound
matches the sound of our real Universe. The second plays the sound
of three Universes with different atomic content : 2%, 4% and 8% of
the total content are atoms (the rest is dark matter and dark energy).
These are more difficult to tell apart, but the middle one (4%) matches
the raw sound of our real Universe. (from slide 58 and slide 61).).
-
Comparison of the "Raw" sound (calculated from the sound spectrum
of the microwave background) and the "Pure" sound (calculated using
CMBFAST). The pure sound removes many distortions which find their way
into the microwave background and is a much closer match to the true
acoustic sound. In this clip, the raw and pure sounds alternate, with
the raw sound first. [For those in the know, the raw sound comes from C(l)
while the pure sound comes from P(k).] (from slide 71).
Cosmic Music: Replacing the Harmonics.
h_1e6_lin_NF3mVD.wav & h_1e6_lin_NF3nVD.wav (all are 219 kb):
-
The first 400,000 years compressed to 10 seconds with varying volume.
The s_ version is the pure (undistorted) sound. This, amazingly, includes
a number of broad harmonics, suggesting the young Universe was behaving
like a musical instrument. However, because the harmonics are broad,
they dont sound like pure tones. To help bring out the "musical nature"
of the sound, one can replace each broad harmonic with a pure tone
of the same pitch and loudness. h_ gives this Musical version. The hs_
version adds these two together, to help our ear hear the harmonics while
keeping its more authentic "rough" form.
The next two sounds repeat the h_ Musical version but with the downward
slide removed (by fixing the 1st harmonic to the A below concert
A) This now allows our ears to hear the subtly changing chord. The
NF3mVD version has the exact (microtonal) pitches while the NF3nVD
version has the pitches forced to our tempered scale, which gives the
discrete changes as the true tones wander between our tempered notes.
(From Slide 88 which shows the
changing harmonics graphically & musically)
h_1e4_3e6_log_NF3mCD.wav & h_1e4_3e6_log_NF3nCD.wav & h_1e4_3e6_log_NF1nCD.wav (219 kb each)
-
Essentially exactly the same as the versions above, but for the first
10 million years played with exponential time (2 seconds per factor of
10 in time) and constant volume. There is one additional version (NF1nCD)
which places all harmonics into a single octave, giving a compact chord.
(from slide 83 and slide 85).).
Sounds From The Newborn Universe
-
This selection includes essentially all sounds and movies from the main narrative ("3b: Full Presentation" found on my
homepage).
There are 16 themes spanning 168 slides, which is how the files are
organized here, with the slide number indicated. A small GIF image of
the slide is also
available, as well as a few selected slides which don't have associated
sounds or movies.
1: Introduction & Overview
-
The sound from the first million
years after the big bang, compressed to 10 seconds (1 second per 100,000 years),
and with the volume held constant.
2: The First Million Years
3: The Microwave Background
4: Cosmic Acoustics
-
The sounds from a Clarinet and Flute playing the same note. The difference
in sound is visible in the two sound spectra. (Taken from Joe Wolfe's
work at UNSW).
5: The CMB Sound Spectrum
-
The raw sound constructed
from the observed angular power spectrum of the microwave background.
6: Origins of Cosmic Sound
7: Using Sound to Measure the Universe
-
A sequence of raw sounds for Universes spanning a range of density,
from 50% of "closure" density, to 150%. The denser Universes have the
deeper voice. The true Universe seems to have exactly the closure density,
ie 100%. The power spectra were calculated using CMBFAST --
the computer simulation of the early universe.
-
Two sequence of raw sounds for Universes spanning a range of atomic
content. The first sequence spans the range 10% to 90% of the "closure"
density in atoms. The second spans the range 2% to 10%. The true Universe
has 4% atomic content.
8: Removing Distortion: From C(l) to P(k)
-
Comparison of the "Raw" sound (taken directly from the power spectrum of
the microwave background) and the "Pure" sound (calculated using CMBFAST).
The pure sound has now removed many distortions which find their way
into the microwave background. It is a much closer match to the true
acoustic sound. In this clip, the raw and pure sounds alternate, with
the raw sound first.
-
Comparison of pure frequency and spread of frequencies, centered on 200
Hz; 600 Hz and 1000 Hz. This shows how a range of frequencies makes an
indistinct note. Similarly, the cosmic harmonics don't sound like notes
to our ears because
they too contain a spread of frequencies.
9: Evolving Sounds
-
Pure cosmic sounds from three different times: 400,000 years; 50,000 years;
1000 years. Earlier times have higher pitches. (The z values in the names
signify the redshift corresponding to the time, ie by what factor the Universe
was smaller.)
-
Quicktime movie showing the changing sound spectrum across the first
400,000 years, together with the changing sound waveform and sky color.
Bars at the
top allow you to follow the changing cosmic size and time.
bar_linW.mov (381 kb movie) & s_4e5_lin_V.wav (313 kb matching sound)
-
Quicktime movies of the same time period (first 400,000 years) but
showing
just the sound spectrum, with a simple bar crossing to track time.
bar_linF uses frequency, while bar_linW uses wavelength to plot the
sound spectrum.
The accompanying sounds are also given as a separate files. lin_C plays
the sound a constant volume, while lin_V follows the true change in
volume
(the volume increases as time passes).
10: Fun with Chord Analysis
-
Compares Raw, Pure, and Musical versions of the sound from about 300,000
years. The Raw and Pure versions were played in slide 71. The Musical
version has replace all the broad harmonics with single tones of the
appropriate frequency and loudness. This renders the sound suitable
for our ears, since we don't discern notes from broad harmonics (see
slide 72). The Musical version is essentially a chord with a number of
interesting intervals in it, including a major third and a minor third.
-
Three versions of the first 10 million years of sound, played with an
exponential time such that 2 seconds elapse for the intervals: 100 to 1000
years, 1000 to 10,000 years, 10,000 to 100,000 years, etc. In all cases
the volume has been held fixed (otherwise the latter times would drown
out the earlier times). s_.wav gives the "Pure" sound, with distortions
removed (using CMBFAST) but keeping the broad harmonics. h_.wav gives
the Musical sound, where the first 8 harmonic peaks have been replaced
by pure tones. hs_.wav has added these together so that one hears both
the natural sound as well as the hidden harmonics. Related versions, but
with the downward slide removed are given in slide 85.
-
Three Musical versions (ie harmonic peaks replaced by pure tones) of
the period 10,000 to 3 million years, played with exponential time as
in slide 83. In these versions the downward slide in pitch has been
removed (by anchoring the first harmonic to 220 Hz), allowing
our ear to hear the subtle changes in the chord. NF3mCD gives the
"microtonal" version, which means that the true frequencies relative to
the lowest harmonic are reproduced exactly. In this case, tones which
are not on our musical scale are included. The NF3nCD version
forces all tones to be played at the pitch of the closest note in our
musical (tempered) scale. These notes change abruptly as the slowly
drifting harmonics shift closer or further from specific tempered notes.
The NF1nCD version also uses the tempered scale, but puts all harmonics
into a single octave, making a compact chord. In all these versions,
the overall volume has been set to a constant, though the loudness of
the individual harmonics has been allowed to vary appropriately (eg, for
reasons explained in the Presentation, the even numbered harmonics
gradually get weaker after about 200,000 years, and by 1 million years
have essentially gone).
-
The same as slide 83, but for the first 400,000 years with normal
(linear) time and a (correctly) varying volume. As before, the s_
version is the pure (undistorted) sound with broad harmonics. h_ gives
the Musical version, with broad harmonics replaced by pure tones, while
the hs_ version adds the two together.
-
The same as slide 85 but for the first 400,000 years at linear (normal)
time and with varying (increasing) volume. Once again, the downward
slide has been removed to allow our ears to hear the subtly changing
chord. The NF3mVD version has the exact (microtonal) pitches while
the NF3nVD version has the pitches forced to our tempered scale. In
these examples, the volume changes correctly, both overall and for the
individual harmonics. (A single octave version wasn't made).
11: From Sound to Stars
-
Pure (undistorted) sound for the atomic matter (baryons) and dark matter
(cdm) around the time of the microwave background (400,000 years).
Of course, the dark matter doesn't generate true pressure waves,
but this sound has been constructed in the same way as for the atomic
matter, from the spectrum of density variations. The dark matter has
not been subject to the high pressure forces of radiation, and so it
has been able to clump up on very small scales which gives yields the
high pitches giving the hiss. Furthermore, because the dark matter has
not participated in any pressure oscillations, its spectrum contains no
harmonics, hence the hiss is similar to that of "white noise".
-
Pure (undistorted) sound for times after the microwave background,
when the atomic gas is free to fall into dark matter clumps, inheriting
its increasingly loud white noise hiss. (The three times are 400,000;
2 million; and 10 million years). In truth, during these later times,
the atomic gas has lost most/all its former pressure and so it does not
sustain pressure (sound) waves. However, its density structure continues
to evolve, and this is what's been used to create these late-time
sounds.
12: The First 100 Million Years
lilili_1e6V.mov (1500 kb movie) & s_1e6_lin_V.wav (313 kb matching sound)
-
Quicktime movies of the evolving sound spectrum for the first 1 million
years, including the changing sound waveform and sky color. Time unfolds
linearly (normally) in both. The first (lilgli) plots log-loundess
(decibels) and plays the sound at constant volume, while the second
(lilili) plots linear loudness and plays the sound at (correct) varying
volume. The accompanying sounds are also given separately.
lglglg_1e8C.mov (1800 kb movie) & s_1e8_log_C.wav (376 kb matching sound)
-
Quicktime movies of the evolving sound spectrum for the first 100 million
years, including the changing sound waveform and sky color. Time unfolds
exponentially in both (2 seconds for each factor of 10 starting at 100
years). The first (lilglg) has a linear frequency axis while the second
(lglglg) has a logarithmic frequency axis. The true volume changes too
much to render, so a "faked" varying volume is given to the first, to
give the feel for the extreme increase in volume. At the end of this
time period, 100 million years after the Big Bang, the first generation of
stars is about to be born.
13: Expanding Horizons
14: Quantum Hiss
-
The so-called "Initial Power Spectrum" (IPS) rendered acoustically. This
is the spectrum to emerge from inflation and provides the template for
all future development of sound and structure. Only as time passed, and
causal horizons moved out, could the gas begin to form sound waves. So
this sound is really a "latent" sound, waiting to emerge. The second
sound file illustrates the response of the Universe, after 400,000 years,
to this initial spectrum. After repeating the IPS sound, we then hear the
dark matter and the atomic matter. Both have had their higher pitches
supressed, though for rather different reasons -- the dark matter only
experiences the supression associated with perturbations entering the
horizon, while the atomic matter has also experienced a high radiation
pressure which prevents significant compression. Thus, the dark matter
is transformed into a less shrill hiss, while the atomic matter is deep
and laced with harmonics.
15: The CMB Microscope
16: From Sound to the Present
- WARNING this is a large, 54 Mega-byte, file. It shows a computer
simulation of the formation of a star cluster, and illustrates the kind
of processes that might have ocurred 100 million years after the Big Bang
during the birth of the first stars. The simulation is by Matthew Bate.
- WARNING this is a moderately large, 2.4 Mega-byte, file. It shows a
computer simulation of several galaxies merging, and illustrates the kind
of processes that might have been common in the first two billion years
after the Big Bang. The simulation is by Lars Hernquist (I think?!).
-
This shows a computer
simulation of the formation of a large galaxy cluster. The simulated duration
is the entire age of the Universe, starting from an almost uniform distribution
of material. In this simulation, only the dark matter is followed, but it
also illustrates roughly how the stars would also collect. The simulation
is by (yikes, I cant' remember, sorry).
-
This shows a computer simulation of a giant region, several billion
light years across, containing millions of galaxies. The brief movie
spans the full age of the Universe, and shows the formation of "Large
Scale Structure" -- the Tapestry of galaxies that fills the present
day Universe. Recently, the structure of the tapestry has been analysed
and the wavelength of the deepest harmonic has been found, a relic of
the acoustic era, 14 billion years ago. The simulation is by (yikes,
I cant' remember, sorry).
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