This is Spacetime Series twenty seven, Episode nine, for broadcast on the nineteenth
of January twenty twenty four. Coming up on Space Time, the Dark Energy
Survey's unique insight into the expansion of the universe. Europe's Einstein Probe lifts off
on a mission to monitor the X race guys and using Earth's magnetic field to
understand key ancient historical events. All that and more coming up on space Time
Welcome to space Time with Stuart Gary. Back in nineteen ninety eight, astrophysicists
discovered that the universe was expanding at an ever accelerating rate. They attributed this
expansion to a mysterious force they called dark energy. The universe has been expanding
outwards ever since its creation in the Big Bank some thirteen point eight two billion
years ago. Now. Initially, scientists hypothesized that the force of gravity from
all the mass in the universe should be slowing down that rate of expansion.
Eventually, depending on how much mass there is in the universe, the expansion
would finally stop, leaving the universe in a steady state of perfect balance.
Alternatively, if there was enough mass in the cosmos, then gravity could become
the dominating force, causing everything to slowly begin to contract again, accelerating faster
and faster, so eventually everything would crash together and what scientists describe as a
big crunch that could be followed by another big bang, then another big crunch,
and so on. However, that view of the cosmos changed in the
nineteen nineties as astronomers began studying distant thermonuclear type one A supernovae. The stars
would create the supernovae all exploded about the same mass and consequently with the same
explosive power and hence luminosity. So by using the inverse square law, astronomers
can determine how far away these supernovae are. Unexpectedly, astronomers found more than
fifty of these supernervae were fainter than what they should be for their measured redshift,
that is, how quickly it's moving away from Earth due to the expansion
of the universe, and consequently how far away they are. Some unknown force,
which astronomers call dark energy dark because they don't know what it is,
it's causing space time to expand at an ever accelerating rate. Now it's worth
pointing out the idea of a dark energy force isn't new. It was first
invented by Albert Einstein back in nineteen seventeen. See, like most scientists of
his day, Einstein just naturally assumed that the universe was stable and everything in
it was in balance, just as it should be. The trouble is his
own field acquis were showing that in such a universe, gravity would have been
the dominating force, crushing everything together. Einstein felt he was missing something,
but he couldn't work out what it was, so he simply invented an expansion
force for the energy density of space, a sort of vacuum energy, if
you will. It was designed to counter gravity in his gravitational field equations,
thereby creating a cosmological constant to return the universe to a steady state. However,
Einstein was forced to abandon the idea of a cosmological concept in nineteen thirty
one after astronomer Edwin Hubble discovered that everything in the universe really was expanding away
from everything else, and the further away from us something is the faster it's
expanding. This forced Einstein to describe his cosmological constant as his biggest blunder.
The recent discovery that the rate at which space time is expanding is accelerating,
has now resurrected the cosmological constant, which, if correct, would automately lead
to what astronomers are calling the Big Freeze, in which all the galaxies would
eventually expand so far away from each other. Only our local galactic group would
remain together in what would be a very cold, dark and empty universe.
And if that's not frightening enough, a more extreme version of dark energy,
called phantom energy, could see the forces involved increase so much that they would
eventually lead to what scientists are calling the Big Rip. A big rip would
see the expansion of space time occur not just on the cosmic scale of relativity
theory, but also on the subatomic scale of quantum mechanics, ripping apart atoms
into the constituent protons, neutrons, and electrons, and even overcoming the force
of gluons in side protons and neutrons to rip off quarks. Now, twenty
five years after the initial discovery of dark energy, scientists working on the Dark
Energy Survey have released the results of an unprecedented analysis using the same technique.
The further probe the mysteries of energy and the expansion of the Universe. The
Dark Energy Survey is an international collaboration comprising more than four hundred astrophysicists, astronomers,
and cosmologists from more than twenty five institutions around the world. Led by
members of the US Department of Energy's FERMI National Accelerated Laboratory, the survey mapped
in area almost one eighth of the entire sky using especially built Dark Energy Camera,
a five hundred and seventy megapixel digital device built by Fermi Lab and funded
by the US Department of Energy's Office of Science. It was mounted on the
Victor M. Blanco Telescope of the National Science Foundation Sarah Tololo Inter American Observatory,
a program of the National Science Foundation's NORI Lab. They've been at a
place the strongest possible constraints on the expansion of the universe ever obtained with the
Dark Energy Supernova Survey. Their report in the Astrophysical Journal has covered some fifteen
hundred new high redshift type one A supernovae using the full five year data set
of the survey, and the results are consistent with an outstandard cosmological model of
the universe with an accelerated expansion, yet the findings are not definitive enough to
rule out a possible more complex model. The Dark Energy Survey scientists took data
for seven hundred and fifty eight nights across six years to understand the nature of
dark energy and measure the expansion rate of the universe. The scientists performed analysis
with four different techniques, including the supernova technique used in nineteen ninety eight.
Astrophysicists traced out the history of cosmic expansion with large samples of supernovae spanning a
wide range of distances. For each supernova, they combine its distance with a
measurement of its red shift. They can use that history to determine whether the
dark energy density has remained constant or whether it's changed over time. Dark Energy
Survey Director Rich Crohn from FERMILABS says that as the universe expands, the matter
density goes down, but if the dark energy density is constant, that means
the total proportion of dark energy must be increasing as the volume decreases. The
standard cosmological model, known as Lambda cold dark matter is based on dark energy
density being constant over cosmic time. It tells us how the universe evolves using
just a few features, such as the density of matter, the type of
matter, and behavior of dark energy. The supernova method constrains two of these
features very well, matter density and a quantity called W, which indicates whether
the dark energy density is constant or not. Now, according to the standard
cosmological model, the density of dark energy in the universe is constant, which
means it doesn't dilute as the universe expands. Now, if this is true,
then the parameter represented by the letter W should equal minus one, and
the result found for W wass zero point eight zero plus or minus zero point
one eight. Using supernova data alone, now combined with complementary data from the
European Space Agency's Plank telescope, W reaches the minus one within the error bars.
But those error bars are important. It means W is tatalizing but not
exactly on minus one, but it's close enough that it is consistent with minus
one. Still, a more complex model might yet be needed in order to
determine if dark energy may indeed vary with time. To come to a definitive
conclusion, scientists will need more data. The problem is the Dark Energy Survey
won't be able to provide that data because the survey stopped taking data in January
twenty nineteen. The final dark energy supernova analysis made many improvements upon the survey's
first super and ova result, which was released in twenty eighteen that used just
two hundred and seven supernovae and three years of data. For the twenty eighteen
analysis, scientists combined data about the spectrum of each supernova in order to determine
their red shift and to classify them as a tie or not. They then
used images taken with different filters in order to identify the flux at the pick
of the light curve, a method called photometry. The problem is spectra are
hard to acquire, requiring lots of observing time on the largest telescopes, and
that will be impractical for future dark energy surveys like the Legacy Survey of Space
and Time, which will be conducted on the vera's Sea Roubn Observatory. So
the new study will pioneer a new approach using photometry, with an unprecedented four
filters being used in order to define the supernerva, classify them, and measure
their light curves. Follow up spectroscopy of the host galaxy using the Anglo austrain
telescope at Siding Spring will provide precise redshifts for every supernerva. The use of
the additional filters will also enable data to be more precise than previous surveys.
It's all a major advancement compared to the original nineteen ninety eight supernova samples,
which only used one or two filters. The Dark Energy surveys searchers used advanced
machine learning techniques and artificial intelligence to aid in supernova classification. Among the data
from about two million distant galaxies observed, the Dark Energy Survey found several thousand
supernovae. Scientists ultimately used one thy four hundred and ninety nine Type one A
supernervee with high quality data, making it the largest deepest supernova sample for a
single telescope ever compiled. Back in nineteen ninety eight, astronomers used just fifty
two supernervay to determine that the universe was expanding at an accelerating rate. So
when you think about it, it's really been a massive scale up in just
twenty five years. Of course, the r minor drawbacks with a new photometric
approach compared to spectroscopy. Since the supernervay do have spectra, there's greater uncertainty
in classification. However, the much larger sample size enabled by the photometric approach
more than makes up for this. The innovative techniques the Dark Energy Survey's pioneered
will shapen further drive future estrophysical analyzes projects like the VERA ce Ubon Legacy Survey
of Space and Time. And that'sa's Nancy Grace Retman Space Telescope. We'll pick
up with a dark energy survey left off this report from Fermi Lab and the
United States Department of Energy. I'm a member of the Dark Energy Survey Collaborations
and I'm here on Sarah Talolo, working to help commission the new dark energy
camera that we've just installed on the Blanco telescope. The whole purpose of our
project is to understand what is dark energy. Dark energy was discovered using in
part this very telescope, and it was discovered by its effect on the universe.
So dark energy is our name, and it's just a name that we
give to the phenomenon that's causing the universus expansion to accelerate. We're not trying
to figure out if dark energy exists. We're not trying to find it.
We know dark energy exists. We're trying to characterize it. We're trying to
understand what it does to us, what it does to the universe, to
its expansion rate, and to the gravitation attraction of things like galaxies. I
work with the Dark Energy Survey and I am working on CISPY, which is
the softer end of the camera, and right now we are in the control
room for the camera. We're doing a survey, so we want to cover
a large section of the sky over five years. The Dark endges of Survey,
we'll scan five thousand square degrees of sky far back in time and far
away from us, in order to measure the distances of supernovae and the distributions
of galaxies. Since we're covering a large section of the sky, we've got
to move the camera to cover all of it, and we have to track
the sky as it moves, because the sky moves very fast, and we're
doing long enough exposures that if we weren't following the sky as it moved,
it would get blurry. We are at an observatory and we're looking at the
stars, and you don't see the stars in the daylight, so generally the
observers will start working sort of around twilight, around dinner you can start taking
some calibration frames and dome flats. You can do those when the daylights out,
but you can't open the dome till after dark. And so right now
it's about twelve twenty, and this is very early in the night for an
astra and so an astronomer will generally stay here and work until sunrise when you
can't take any more data. Every time I come to Sarah to Loolo,
I realize how special an experience it is. Last night when we were looking
up at the sky and when you could see the Milky Way so clearly,
but you know that as a galaxy, it's a line. You know that
the plane of it is a line, and you see a curved across the
sky. What else can that do to you but make you feel like you're
like you're on this sphere with all these other people, with the people here
on the mountain but everyone else, like you know that you're home. In
so many ways, this job is a whole lot of fun. I've really
enjoyed seeing from At first, all I was seeing was the software and it
was very abstract, and it's been really neat to see first the telescope simulator
being built at for ME Lab, and then just to come here to Chili
and be able to actually see the telescope take data. It's really exciting in
some sense the purpose of our experiment and what we'll learn by understanding more about
what dark energy is to find out about the fate of the universe. What
is going to happen into the future. Is the universe really going to keep
expanding faster and faster and faster or not. Over three hundred people from professors
to engineers to students and postdocs putting together the Dark Energy Survey and all the
infrastructure, from simulations to theory and everything that went into making the survey possible.
One might think, oh, and you know, I'm just one little
piece in this large process. But when you think again about what we're exploring,
when you think about the images that we're going to take, when you
think about how far and away and how far back in time we're going to
look, you can't help but feel like you're a part of something that's really
important, that's helping us see not just about the past of the universe,
but the past of us, where we've been and really where we're going to
go. And in that report from FERMI Lab and the US Department of Energy,
weird from Aaron Rudman from the Stanford Linear Accelerated Center, Brian Nord from
FERMI Lab, and Elliot from Ohio State University. This space time still to
come, Europe's Einstein Probe lifts off on a mission to monitor the X ray
skies and using Earth's magnetic field to better understand ancient historical events. All that
and more still to come on space time. The European Space Agency the Max
Planck Institute in China have joined forces to launch the new Einstein X ray space
Telescope into orbit. The Einstein Observatory will survey the sky, hunting for bursts
of X ray light and other high energy astrophysics from objects such as neutron stars
and black holes. The mission was launched about a long March two sea rocket
from the Jai Chang Satellite Launch Center and Sichuan pro in southwestern China. The
four hundred and fifty kilogram probe was placed into a six hundred kilometer high orbit,
circling the planet every ninety six minutes at an inclination of twenty nine degrees,
thereby allowing it to monitor almost the entire sky in just three orbits.
Over the next six months, mission managers will test and calibrate the instruments before
its initial three years scientific mission begins. The probe is equipped with both a
wide field X ray telescope and a follow up X ray telescope. The optics
of the wide field X ray telescope were inspired by the compound eyes of lobsters
in a modular layout employing hundreds of thousands of square fibers that channel light under
the detectors. This gives the probe the unique capability of observing nearly a tenth
of the celestial sphere in a single glance. New X ray sources spotted by
the wide field X ray telescope and then be targeted with a follow up X
ray telescope, which is a narrow field of view but is more sensitive and
able to capture more details. The ability of the Einstein telescope to spot U
X ray sources and then monitor how they change over time is fundamental to improving
sciences grasp of some of the most energetic processes in the universe. These include
powerful blasts of X rays that occur when neutron stars collide, when supernovae explode,
and when matter is swallowed by black holes or ejected by the crushing magnetic
fields that envelop black holes. The Einstein prob will also enables scientists to catch
X ray light from collisions between neutron stars and find out what's causing some of
the gravitational wave events detected. Often, when these elusive space time gravitational wave
ripples are registered, astronomers are unable to locate the sources quickly enough, But
by promptly spotting a burst of X rays from one of these events, scientists
might be able to better pinpoint the origin this space time still to come using
a magnetic field to better understand key ancient historical events, and later in the
Science report, the new study that identifies the bacteria that inhabits human air piercings
all that and more still to come on space time. Archaeologists have used changes
in Earth's magnetic field provide the most accurate yet dating techniques for archaeological finds.
The new technique, which has been reported in the journal plus one, scientifically
corroborates an event first described in the Old Testament Second Book of Kings the conquest
of the Philistine city of Gath now Telesafi in central Israel by Hazil, king
of Aram. The method developed by Tel Aviv University, the Hebrew University of
Jerusalem, Baharan University, and Arial University is based on measuring the magnetic field
corded in burnt bricks, which were the primary building material of the time.
The new findings are important for determining the intensity of the fire and the scope
of destruction ingaff which was the largest and most powerful sitting in the region at
that time, and also for understanding the construction practices of the day. See
throughout the Bronze and Iron ages. The main building material in most parts of
the Land of Israel were mud bricks. This cheap and readily available material was
used to build the walls of most buildings, sometimes on top of stone foundations.
But during the same time, dwellers of other lands such as Mesopotamia,
where stones were hard to come by, would fire mud bricks inside kilns in
order to increase their strength and durability. This technique is mentioned in the story
of the Tower of Babel in the Book of Genesis or at states, and
I'm quoting here, they said one to another, come let us make bricks
and fire them thoroughly. So they used bricks for stone Genesis eleven. Most
researchers, however, believe this technique didn't reach the land of Israel until much
later, with the Roman conquest. It was also during the time of the
Roman conquest that the land of Israel was renamed Palestine or Pallistia to be more
accurate. But until the Roman conquest, the inhabitants of Israel use sun dried
mud bricks. The new magnetic earth dating method relies on measuring the magnetic field
recorded and locked into a brick at the time it was burned and cooled down.
See The clay from which the bricks were being made contained millions of tiny
ferromagnetic particles minerals with magnetic properties to behave like very tiny compasses or magnets.
In sun dried mud bricks. The orientation of these magnets is virtually random,
so that they cancel one another out. Therefore, the overall magnetic signal from
a brick which has been dried in the sun is weak and not uniform.
But by heating a mud brick to two hundred degrees celsius or more inside a
kiln, it releases the magnetic cild signals of these magnetic particles, and statistically,
they tend to align with the outh's magnetic field at that specific time and
place. So when the brick cools down, the magnetic signal remains locked in
that new position, and the brick attains a strong and uniformly oriented magnetic field,
which can be measured with a magnetometer. Then, by reheating the bricks
in a lab under controlled temperatures and magnetic field conditions, the bricks magnetic signature
slowly begins to break down again, and scientists can then determine the temperature at
which the bricks were initially fired. So when bricks are found in an archaeological
excavation, scientists need to determine if the bricks will first fight in a kiln
prior to construction, or if they will fight in situ and say a destructive
event during the burning down of a city. In this way, this new
method can provide a conclusive answer, which is crucial for correctly interpreting the findings.
The new technique can also determine the orientation of the Oarth's magnetic field when
the bricks originally down. Now in Israel this means north and downwards. But
when builders take bricks from m kill and then build a wall, they'll lay
them in a random orientation, thus randomizing the recorded signals. On the other
hand, when a wall is burnt in Situs would happen when the city's being
destroyed by an enemy magnetic field, of all the bricks would be locked in
the same orientation. The real test came when the new method was applied to
the Telessafri archaeological ruins. A prevalent hypothesis based on the Old Testament historical sources
and carbon fourteen dating, attributes the distraction of the structure to the devastation of
Gath by Hazil, king of Aram Damascus, around eight thirty BCE. However,
a different paper proposed that the buildings had not been burned down but had
simply collapsed over decades, and that the fired bricks found that the structure had
been fired in a kiln prior to construction. Now, if this hypothesis were
correct, it would be the earliest instance of brick firing technology discovered in the
land of Israel. To settle the debate. The authors simply applied the new
method to samples from the wall at the dig site and to collapse debris from
around the site, and the findings were conclusive. The magnetic fields of all
the bricks in the walls and the collapse debris around the walls all displayed the
same orientation north and downwards. That means that the bricks were indeed burned and
then cooled down in situe right where they had been found, namely in the
configuration in the structure itself, which collapsed within a few hours. Had the
bricks been fired in a kiln and then laid in the wall, their magnetic
orientations would have been random. Furthermore, had the structure collapsed over time and
not in a single fire event, the collapse debris would also have displayed random
magnetic orientations. So what does it mean, Well, it means the account
of the Bible's Old Testament is essentially correct. These findings are important for deciphering
the intensity of the fire and the scope of the destruction of Gas, the
largest and most powerful city in the Land of Israel at the time, as
well as for understanding the building methods which we used at the time. In
other words, the findings indicate the brick firing technology was probably not being practiced
in the land of Israel at the time of the Kings of Judah and Israel.
This space time and time that to take another brief look at some of
the other stories making news in science this week with a science report, A
new study has found that kids and teens with autism are less likely to undertake
physical activity and have worse sleep patterns than kids and teens who aren't on the
spectrum. The findings, reported in the Journal of the American Medical Association,
found that kids with autism spectrum disordered take longer to form of sleep after lights
out, slept for shorter amounts of time, and had less efficient sleep than
their peers. The gap in physical activity levels between kids on the spectrum and
their peers also got bigger as kids got older, which could be because kids
on the spectrum are less likely to participate in sports with higher social demands,
such as basketball, football, and volleyball. Scientists have discovered that fairy wrens
will help raise the relatives' babies in the hope of having an affair with their
relatives partners. Some fairy rens have been seen having their own chicks in order
to help others raise their brood, something known as cooperative breeding, but the
murtive for this apparently altruistic behavior has always intrigued. Scientists now are reporting the
Journal of the Ray Society Opened Sciences found that these helpers would only help a
relative, and were most likely to help breeding pairs that contained both a relative
that was of the same sex as them and a potential mate. The authors
suggest that the helpers are getting some indirect benefits, such as social bonds,
from helping the realies, and that some are even getting some direct benefits,
possibly from a potential mate. Zero Dear. Scientists in Canada have uncover the
bacteria that inhabit human ear piercings. They found that even though people have their
skin sterilized before a piercing, these sites regularly end up with a greater diversity
of bacteria living there than on regular eelobe skin, and the process of piercing
changes the local microbiome then you. Findings reported in the Journal of the Proceedings
the Raw Society be showed that the piecings cause a shift towards a moist skin
microbiome, which they say could be because the piecings can potentially trap moisture.
The authors say that as well as being a form of culture or religious and
personal expression, ear piercings also represent a form of ecosystem self engineering of the
ecological landscape of the human skin. A British newspaper has used an image of
the shroud of Turin and apply it a little artificial intelligence in order to find
out exactly what Jesus might have looked like. However, as Tim Mendum from
Austrian Skeptics points out, the first problem is whether the shroud itself is real.
We're talking about the shroud. Well, someone just wanted to know what
Jesus looked like, and as you will have seen from most European representations,
he doesn't look like a Middle Eastern person. Looks more like a Norwegian first,
a blonde that of aran. Look at that Norwegian jew that's the one.
Yes, it's the interesting idea. So anyway, trying to think what
Jesus looked like, I'm not going to go into the fact that Jesus exists
with he did. What did he look like? Some have subjected that he
looked very Middle Eastern, so dark here be that someone applied artificial intelligence assessment
to the Shroud of Turin. Now, the Shroud of Turin is supposedly the
story does the material that was wrapped around Jesus again when he was put in
the in a case in the term, et cetera, and that for some
particular supernatural reason, his image was transfer knitted onto the shroud itself, an
electrical discharge, a chemical reaction, whatever, And the shroud first noticed in
about the twelve hundred and seven hundred something like that. That's when the first
references come to it. There's a local bishop who said, there's this guy
showing this cloth around reckons it's the shroud of Jesus, et cetera, and
that we should stop him. Didn't. Then kept on appearing and going through
private hands, and eventually ends up in the Cathedral Tury in Italy, where
they show it every forty years and you get minyes of people coming through to
have a look at it. The emas of Jesus, which is a bit
hard to see. It's not very clear, but if you've photograph it turning
into a negative et cetera, you can apparently see it better. So UK
Daily Star got an ai specialist under with it and looked at the image obviously
not the shroud itself, and looked at an image and then processes and created
a three D version of it. This is not particularly difficult, I think,
I mean doing this with land forms three years so they did this with
the face. Pull it up and you think that's what Jesus. Fuck.
No, first of all, the shroud is probably not real. It's not
the real it's not really of Jesus. And therefore the image on the shroud
it's probably not jess probably not even a true shroud. In fact, that
suggestions it was made at the time of the midiupl eight. You could do
this thing with a Mona Lisa or anything like that to see what he actually
looks like. This is Jesus sounds more important. Yeah, it's a problem
with AI, so that sort of people give it more credence, more sort
of special notice than it really deserves, because in this particular case, there's
something more than that computer generated image, which is pretty easy to do,
I think if you have a bit of technology to hand, but just mention
AI and everything becomes very exciting, super diuper sort of impressive results. There's
a video of the generation of this image, which goes through variations. There
were all different sort of looking Jesus, from a Middle Eastern person to a
Northern European person to FA's then por Harry whatever, which just goes to show
that you can generate any sort of image you like if you remember the technique
of morphing from one photo to another, and you can see the different stages
between the computer generated imagery. I think Michael Jackson used it in a video
clips to one of his songs, you know, and you go from face
to face to face to face and you're morphing from one face to the next.
It doesn't necessarily show that Jesus, for the very paper you can do
these from this one source indicates that you can do. That's tremendum from Ustralian
skeptics. And that's the show for now. Space Time is available every Monday,
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