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Quantum Mechanics Just Got Even More “Spookier” Than Before

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An international collaboration and a newly published paper may have just settled a century old physics debate.

Quantum mechanics is spooky. Entanglement – a component of quantum mechanics – tells us that two particles can be directly connected even across vast distances. If you measure the spin of one particle, you immediately know the spin of its counterpart.


Physicists have labeled this behavior as “spooky” as it doesn’t follow everyday logic. Common sense tells us that objects across the universe cannot possibly be connected, yet in the quantum realm, they are. Quantum mechanics also says that properties of particles are only fixed when the particle is observed.
Some physicists, including Albert Einstein, opposed this notion as it went against the very nature of the real world. In the 1930s when quantum mechanics was an emerging field, Einstein was a proponent of “local realism,” arguing that only close objects could affect each other. Einstein and other physicists developed the ‘hidden variables theory’ to explain the spooky behavior. They argued that our knowledge of quantum mechanics was incomplete and there could be hidden variables that we didn’t yet understand.
In the 1960s a physicist named John Bell devised a mathematical expression – called an inequality – to test for these so-called hidden variables. He realized that if these hidden variables did indeed exist, there would be a limit to how connected the particles were. If they exceeded the set limit then the hidden variables did not exist. However, the experiment – known as Bell’s Inequality – did not definitively close the door on local realism. 

The tests involved entangled photons, which can get lost along the way, and experimenters might not detect all photons produced.
In the new experiment, led by Professor Ronald Hanson of Delft University of Technology in the Netherlands, we have two researchers – we will call them Alice and Bob – in two laboratories 1.3 kilometers apart. Each laboratory is set up with a diamond chip containing an electron whose spin was entangled with a photon. The photons were then sent to a third lab in between Alice and Bob, where a detector records the arrival time. If two photons arrived at the same time they would be entangled, resulting in the electrons being entangled as well.
The experiment took place over a span of nine days. In that time, researchers recorded 245 successful entanglements. While other tests over the last few decades have also supported Bell’s limit, this new experiment learns from their shortcomings to overcome experimental pitfalls. Previous test used inefficient detectors, only measuring a small number of the particles passing through them. Recent experiments used near-perfect detectors, but the entangled particles were close enough to potentially communicate. In the new experiment, the team used high-quality detectors and measurements collected before the electrons could possibly exchange signals with each other, making it the first to close both loopholes.
The results of this experiment have big implications for the world of quantum cryptography – meaning entangled photons could potentially create secure encryption keys. Closing the loopholes would ensure that computer systems could detect if anyone tried to intercept the keys, as it would break the entanglement and trigger an alarm.

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Hubble Telescope Captures Image of the Farthest Star Ever Seen

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Gravitational
lensing has become a remarkably handy tool, as astronomers are refining and
enhancing the ways they can use what has been called “nature’s telescope” to
find objects in the cosmos. Two separate studies published April 2 in the
journal Nature Astronomy describe how gravitational lensing has provided
remarkable views of different types of “extreme” stars that are normally too
far away and dim to be detected.




Because of
unique lensing events, the stars — nicknamed Icarus and Spock — have been
observed multiple times with the Hubble Space Telescope.
In one study, astronomers used gravitational lensing to see Icarus, or MACS J1149
Lensed Star 1, the most distant star ever observed, located about 9 billion
light-years from Earth. Usually, lensing magnifies galaxies by up to 50 times,
but in this case, the star was magnified more than 2,000 times. This is the
first time a “normal” star — one that was not exploding as a supernova — has
been observed at such a great distance.

“You can see
individual galaxies out there, but this star is at least 100 times farther away
than the next individual star we can study, except for supernova explosions,”
Patrick Kelly, from the University of Minnesota, said in a statement. Kelly led
the Icarus study.

Researchers
reported that the two Spock stars, named HFF14Spo-NW and HFF14Spo-SE, were seen
“twinkling,” which, the team writes, is thought to be caused by “separate
eruptions of a luminous blue variable star or a recurrent nova, or as an
unrelated pair of stellar microlensing events.”

For both
studies, however, the brightness seen through the lensing events had one thing
in common: The gravitational lensing was caused by not just one galaxy, but a
cluster of galaxies, which can greatly enhance the effect.
Normally,
gravitational lensing occurs when two galaxies happen to align with one another
along our line of sight in the sky. The gravitational field of the nearer
galaxy acts as a lens, magnifying the light coming from the stars behind them.
In the past, astronomers have used this technique to measure the shape of
stars, search for exoplanets, and measure dark matter in distant galaxies.
In the case
of the two current studies, clusters of galaxies acted as the lens, providing
extreme magnification from the gravitational field generated by multiple
galaxies.

“We have
found that lensed stars behind galaxy clusters should fluctuate in brightness
due to the stars in the clusters, which act as microlenses,” Kelly said in an
email to Seeker.

“So, what we need to do is take very deep observations of the
galaxy-cluster fields, and we should be able to detect the fluctuations of many
stars that are intrinsically fainter than Icarus, which we think is quite
luminous.”

Kelly added
that the launch of the James Webb Space Telescope should be “terrific” for
doing just that, and astronomers are hoping to find many more lensed stars
using the telescope.
In a
commentary about the studies, astronomer Roseanne Di Stefano from the
Harvard-Smithsonian Center for Astrophysics said these types of observations
highlight a new frontier for sky watchers.

“These two
investigations are important,” Di Stefano wrote. “Individually, and even more
so in tandem, they open up a rich field for future discoveries. They show us
that magnified stellar variability and short microlensing events can be
realistically expected from galaxies behind clusters.”

For the
Spock stars, the team wrote that the “discovery suggests that the intersection
of strong lensing with high-cadence transient surveys may be a fruitful path
for future astrophysical transient studies.”

This type of
lensing, both teams said, is providing new views of events and processes we
would otherwise be unable to observe, since faint stars and non-supernova
stellar outbursts are not generally detectable at such great distances.
The
brightening is intermittent, however, because of the movement of the galaxies.
So astronomers need to determine whether the intermittent brightening is a
factor of a transient star, the movement of the galaxy clusters, or other types
of events.
The observed
light from Icarus was emitted about 4.4 billion years after the Big Bang, when
the universe was only about 30 percent of its current age. The prevalence of
galaxy clusters means this effect could be used more frequently to look deeper
into the past, and study the evolution of the earliest stars.

“There are
alignments like this all over the place, as background stars or stars in
lensing galaxies move around, offering the possibility of studying very distant
stars dating from the early universe, just as we have been using gravitational
lensing to study distant galaxies,” said University of California, Berkeley
astronomer Alex Filippenko, who participated in both studies. “For this type of
research, nature has provided us with a larger telescope than we can possibly
build!”

Via Seeker.

Hubble Telescope Captures Image of the Farthest Star Ever Seen

Editor
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0

Gravitational lensing has become a remarkably handy tool, as astronomers are refining and enhancing the ways they can use what has been called “nature’s telescope” to find objects in the cosmos. Two separate studies published April 2 in the journal Nature Astronomy describe how gravitational lensing has provided remarkable views of different types of “extreme” stars that are normally too far away and dim to be detected.



Because of unique lensing events, the stars — nicknamed Icarus and Spock — have been observed multiple times with the Hubble Space Telescope.
In one study, astronomers used gravitational lensing to see Icarus, or MACS J1149 Lensed Star 1, the most distant star ever observed, located about 9 billion light-years from Earth. Usually, lensing magnifies galaxies by up to 50 times, but in this case, the star was magnified more than 2,000 times. This is the first time a “normal” star — one that was not exploding as a supernova — has been observed at such a great distance.

“You can see individual galaxies out there, but this star is at least 100 times farther away than the next individual star we can study, except for supernova explosions,” Patrick Kelly, from the University of Minnesota, said in a statement. Kelly led the Icarus study.

Researchers reported that the two Spock stars, named HFF14Spo-NW and HFF14Spo-SE, were seen “twinkling,” which, the team writes, is thought to be caused by “separate eruptions of a luminous blue variable star or a recurrent nova, or as an unrelated pair of stellar microlensing events.”

For both studies, however, the brightness seen through the lensing events had one thing in common: The gravitational lensing was caused by not just one galaxy, but a cluster of galaxies, which can greatly enhance the effect.
Normally, gravitational lensing occurs when two galaxies happen to align with one another along our line of sight in the sky. The gravitational field of the nearer galaxy acts as a lens, magnifying the light coming from the stars behind them. In the past, astronomers have used this technique to measure the shape of stars, search for exoplanets, and measure dark matter in distant galaxies.
In the case of the two current studies, clusters of galaxies acted as the lens, providing extreme magnification from the gravitational field generated by multiple galaxies.

“We have found that lensed stars behind galaxy clusters should fluctuate in brightness due to the stars in the clusters, which act as microlenses,” Kelly said in an email to Seeker.

“So, what we need to do is take very deep observations of the galaxy-cluster fields, and we should be able to detect the fluctuations of many stars that are intrinsically fainter than Icarus, which we think is quite luminous.”

Kelly added that the launch of the James Webb Space Telescope should be “terrific” for doing just that, and astronomers are hoping to find many more lensed stars using the telescope.
In a commentary about the studies, astronomer Roseanne Di Stefano from the Harvard-Smithsonian Center for Astrophysics said these types of observations highlight a new frontier for sky watchers.

“These two investigations are important,” Di Stefano wrote. “Individually, and even more so in tandem, they open up a rich field for future discoveries. They show us that magnified stellar variability and short microlensing events can be realistically expected from galaxies behind clusters.”

For the Spock stars, the team wrote that the “discovery suggests that the intersection of strong lensing with high-cadence transient surveys may be a fruitful path for future astrophysical transient studies.”

This type of lensing, both teams said, is providing new views of events and processes we would otherwise be unable to observe, since faint stars and non-supernova stellar outbursts are not generally detectable at such great distances.
The brightening is intermittent, however, because of the movement of the galaxies. So astronomers need to determine whether the intermittent brightening is a factor of a transient star, the movement of the galaxy clusters, or other types of events.
The observed light from Icarus was emitted about 4.4 billion years after the Big Bang, when the universe was only about 30 percent of its current age. The prevalence of galaxy clusters means this effect could be used more frequently to look deeper into the past, and study the evolution of the earliest stars.

“There are alignments like this all over the place, as background stars or stars in lensing galaxies move around, offering the possibility of studying very distant stars dating from the early universe, just as we have been using gravitational lensing to study distant galaxies,” said University of California, Berkeley astronomer Alex Filippenko, who participated in both studies. “For this type of research, nature has provided us with a larger telescope than we can possibly build!”

Via Seeker.

Sunrise in 7 billion years: Red Giant Sun

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In
approximately 5 billion years, the sun will begin the helium-burning process,
turning into a red giant star. When it expands, its outer layers will consume
Mercury and Venus, and reach Earth.



Here is what
sunrise will look like in 7 billion years when Sun turns into Red Giant Sun.






Sunrise in 7 billion years: Red Giant Sun

Editor
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In approximately 5 billion years, the sun will begin the helium-burning process, turning into a red giant star. When it expands, its outer layers will consume Mercury and Venus, and reach Earth.


Here is what sunrise will look like in 7 billion years when Sun turns into Red Giant Sun.





4 Crazy Things About Quantum Physics That Everyone Should Know

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Quantum
mechanics is the body of scientific laws that describe the wacky behavior of
photons, electrons and the other particles that make up the universe. Quantum
mechanics is the branch of physics relating to the very small. It results in
what may appear to be some very strange conclusions about the physical world. 







Quantum mechanics (QM; also
known as quantum physics or quantum theory), including quantum field theory, is a branch of physics which is the
fundamental theory of nature at
the smallest scales of energy levels of atoms and subatomic particles. In the video
below from The Science Asylum, Nick Lucid explains some creepy things about
quantum physics like, wave-particle duality and other stuff like that. So watch
and learn:


4 Crazy Things About Quantum Physics That Everyone Should Know

Editor
-
0
Quantum mechanics is the body of scientific laws that describe the wacky behavior of photons, electrons and the other particles that make up the universe. Quantum mechanics is the branch of physics relating to the very small. It results in what may appear to be some very strange conclusions about the physical world. 



Quantum mechanics (QM; also known as quantum physics or quantum theory), including quantum field theory, is a branch of physics which is the fundamental theory of nature at the smallest scales of energy levels of atoms and subatomic particles. In the video below from The Science Asylum, Nick Lucid explains some creepy things about quantum physics like, wave-particle duality and other stuff like that. So watch and learn:


Astronomers Just Zoomed Stunningly Close to The Event Horizon of Our Galaxy’s Black Hole

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Telescopes around the world have joined forces to try to provide us with our first photograph of a black hole. That’s still a few months off, at least, but all that staring at a black hole is already starting to produce results.

In 2013, the Atacama Pathfinder Experiment (APEX) radio telescope in Chile joined the global telescope collective that makes up the Event Horizon Telescope (EHT), to take observations of Sagittarius A*, the supermassive black hole at the centre of our galaxy.


And it almost doubled the longest baseline length in the array, leading to observation of the finest details yet of the space right around the event horizon of this black hole.
Now, we can’t actually see black holes. They’re thought to be incredibly dense collapsed stars with a gravitational pull so strong that nothing, not even light, can escape – and if there’s nothing coming out of them, we can’t detect them.
What we can detect is the space around them, along with matter as it falls into the black hole’s gravitational tug, forming a swirling accretion disc that glows with the intense heat of friction. However, at a certain distance from the black hole, there is no escape, and everything falls in. Even light. This point of no return, where the escape velocity is higher than light speed, is called the event horizon, and this is what the Event Horizon Telescope is trying to photograph.
Some black holes are absolutely immense, like Sagittarius A*, which is millions of times the mass of the Sun. These are way bigger than any stars that we know of, and astronomers are not quite sure how they form. But a bigger object means it’s easier to see – and that’s why the EHT is looking at the closest one we know.

The 2013 observations of Sagittarius A* narrowed down the resolution to just three Schwarzschild radii – one of which equals the radius of the event horizon, or the hypothetical size of the black hole – revealing details as small as 36 million km (kilometers).
This may seem huge – after all, Earth is 150 million kilometers from the Sun – but it’s smaller than the expected size of the accretion disc, and has allowed astronomers to start figuring out the event horizon’s structure by working out models and applying them to the data.

“We started to figure out what the horizon- scale structure may look like, rather than just draw generic conclusions from the visibilities that we sampled,” explained astronomer Ru-Sen Lu of the Max Planck Institute for Radio Astronomy (MPIRA).

“It is very encouraging to see that the fitting of a ring-like structure agrees very well with the data, though we cannot exclude other models, e.g., a composition of bright spots.”

So it’s looking like the structure of the space around the event horizon of Sagittarius A* could be shaped like a giant doughnut around the black hole. Which could explain why it gets so hungry. Of course, the data isn’t detailed enough yet to draw any firm conclusions. Future observations by the EHT will get more data in order to build up a more comprehensive picture. But, so far, this is pretty exciting stuff.

“The results are an important step to ongoing development of the Event Horizon Telescope,” said Sheperd Doeleman from the Harvard-Smithsonian Center for Astrophysics and director of the EHT.

“The analysis of new observations, which since 2017 also include ALMA, will bring us another step closer to imaging the black hole in the centre of our Galaxy.”

The research has been published in The Astrophysical Journal.

Astronomers Just Zoomed Stunningly Close to The Event Horizon of Our Galaxy’s Black Hole

-
0

Telescopes
around the world have joined forces to try to provide us with our first
photograph of a black hole. That’s still a few months off, at least, but all
that staring at a black hole is already starting to produce results.

In 2013, the
Atacama Pathfinder Experiment (APEX) radio telescope in Chile joined the global
telescope collective that makes up the Event Horizon Telescope (EHT), to take
observations of Sagittarius A*, the supermassive black hole at the centre of
our galaxy.



And it
almost doubled the longest baseline length in the array, leading to observation
of the finest details yet of the space right around the event horizon of this
black hole.
Now, we
can’t actually see black holes. They’re thought to be incredibly dense
collapsed stars with a gravitational pull so strong that nothing, not even
light, can escape – and if there’s nothing coming out of them, we can’t detect
them.
What we can
detect is the space around them, along with matter as it falls into the black
hole’s gravitational tug, forming a swirling accretion disc that glows with the
intense heat of friction. However, at a certain distance from the black hole,
there is no escape, and everything falls in. Even light. This point of no
return, where the escape velocity is higher than light speed, is called the
event horizon, and this is what the Event Horizon Telescope is trying to
photograph.
Some black
holes are absolutely immense, like Sagittarius A*, which is millions of times
the mass of the Sun. These are way bigger than any stars that we know of, and
astronomers are not quite sure how they form. But a bigger object means it’s
easier to see – and that’s why the EHT is looking at the closest one we know.

The 2013
observations of Sagittarius A* narrowed down the resolution to just three
Schwarzschild radii – one of which equals the radius of the event horizon, or
the hypothetical size of the black hole – revealing details as small as 36
million km (kilometers).
This may
seem huge – after all, Earth is 150 million kilometers from the Sun – but it’s
smaller than the expected size of the accretion disc, and has allowed
astronomers to start figuring out the event horizon’s structure by working out
models and applying them to the data.

“We
started to figure out what the horizon- scale structure may look like, rather
than just draw generic conclusions from the visibilities that we sampled,”
explained astronomer Ru-Sen Lu of the Max Planck Institute for Radio Astronomy (MPIRA).

“It is
very encouraging to see that the fitting of a ring-like structure agrees very
well with the data, though we cannot exclude other models, e.g., a composition
of bright spots.”

So it’s
looking like the structure of the space around the event horizon of Sagittarius
A* could be shaped like a giant doughnut around the black hole. Which could
explain why it gets so hungry. Of course, the data isn’t detailed enough yet to
draw any firm conclusions. Future observations by the EHT will get more data in
order to build up a more comprehensive picture. But, so far, this is pretty
exciting stuff.

“The
results are an important step to ongoing development of the Event Horizon
Telescope,” said Sheperd Doeleman from the Harvard-Smithsonian Center for
Astrophysics and director of the EHT.

“The
analysis of new observations, which since 2017 also include ALMA, will bring us
another step closer to imaging the black hole in the centre of our
Galaxy.”

The research
has been published in The Astrophysical Journal.

There is no “Fourth” dimension

Editor
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Okay, here’s the thing. There is no fourth dimension. Mind not blown by that? How about this – there is no third dimension either. Before you start yelling at your smartphone about how the Universe is made up of three dimensions, just settle down and let the episode of MinutePhysics below explain this rather tricky misconception.



Anyone with a basic understanding of dimensions could tell you that an object with height, width, and depth is three-dimensional, and something with height, width, but no depth – say a drawing on a piece of paper – is two-dimensional. 


Just because there are four dimensions doesn’t mean there’s a “fourth dimension”. Learn more in the video below:


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All About Space. We are curious about the Universe, are you?

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