Noble Prize for black holes
Three Laureates share this year’s Noble Prize in
Physics for their discoveries
about one of the most exotic
phenomena in the universe,
the black hole.
Roger Penrose showed that the general
theoryof relativity leads
to the formation of black holes.
Reinhard Genzel and Andrea Ghez
discoveredthat an invisible and
extremely heavy object governs
the orbits of
stars at the centreof our galaxy.
A supermassive black hole is the
only currently
known explanation.
Roger Penrose used ingenious mathematical
methods, Noble prize
in his proof that black holes are a
direct consequence of
Albert Einstein’sgeneral theory of relativity.
Einstein did not himself believe
that blackholes really exist,
these super-heavyweight monsters
that capture everything that entersthem.
Nothing can escape, not even light.
Reinhard Genzel and
Andrea Ghez each leada group of astronomers
who have focused on a region at the centre
of the Milky Way sincethe early 1990s,
Nobel Prize.
With increasing precision,
they have mappedthe orbits of the brightest stars
that are closest to the centre.
Both groups found
something that is
both invisibleand heavy,
forcing this jumble of stars to swirl around.
Noble Prize For Black Hole
This invisible mass has about four
millionsolar masses
squeezed together in a region no
larger than our solar system.
What is it that makes the stars at
the heartof the Milky
Way swing around at such astonishing speeds?
According to the current theory of gravity,
there is only one candidate
– a supermassive black hole and
Nobel Prize.
Not even Albert Einstein,
Nobel Prize,
the father of generalrelativity,
thought that black holes could actually exist.
However, ten years after
Einstein’s death,
the British theorist Roger Penrose
demonstrated that
black holes can form and
described theirproperties.
At their heart, black holes
hide a singularity,
a boundary at which all the known
laws of nature break down.
Legends
To prove that black hole formation is a stableprocess,
Penrose needed to expand the methods used to
study the theory of relativity –
tacklingthe theory’s problems with
new mathematical concepts.
Penrose’s ground-breaking article was publishedin
January 1965 and
is still regarded as the most important
contribution to the generaltheory
of relativity since Einstein,
Nobel Prize.
Black holes are perhaps the strangest
consequenceof the general theory of relativity.
When Albert Einstein presented his theoryin November 1915,
it upended all the previous concepts of space and
time and get noble prize.
Noble Prize in 2020
The theory provided an entirely new foundation
for understanding gravity,
which shapes the universe at the largest scale.
Since then, this theory has provided the
basisfor all studies of the universe,
and also has a practical use in one of our most
commonnavigation tools, the GPS.
Einstein’s theory describes how everythingand
everyone in the
universe is held in the grip of gravitation.
Gravity holds us on Earth,
it governs theorbits of the planets around the Sun
and the orbit of the Sun around the centre of theMilky Way.
It leads to the birth of stars from interstellarclouds,
and eventually their death in a gravitational collapse.
Gravitation brings shape to space and
influencesthe passage of time.
A heavy mass bends space and slows time;
Nobel Prize,
anextremely heavy mass can even cut off and
encapsulate a piece of space –
forming ablack hole.
The first theoretical description of whatwe
now call a black hole
came just a few weeks after the publication
of the general theoryof relativity.
Despite the theory’s extremely complicated
mathematical equations,
the German astrophysicist Karl Schwarzschild
was able to provide Einstein
with a solution that described how
heavy masses can bend space and time.
Noble Prize Researchers
Later studies showed that once a black holehas formed,
it is surrounded by an event horizon that sweeps
around the mass at its centrelike a veil.
The black hole remains forever hidden insideits event horizon.
The greater the mass, the larger the blackhole and its horizon.
For a mass equivalent to the Sun,
the eventhorizon has a diameter of almost three kilometres and,
for a mass like that of the Earth,
itsdiameter is just nine millimetres.
The concept of the ‘black hole’ has foundnew
meaning in many forms of cultural expression but,
for physicists, Nobel Prize
black holes are the naturalend point
of the evolution of giant stars.
The first calculation of the dramatic collapse
of a massive star was made
at the end of the 1930s,
by physicist Robert Oppenheimer,
wholater led the Manhattan Project that
constructed the first atomic bomb.
When giant stars, many times heavier thanthe Sun,
run out of fuel,
they first explode as supernovas and then
collapse into extremely
densely packed remnants,
so heavy that gravity pulls everything inside, even light.
History of Nobel Prize
The idea of ‘dark stars’
was consideredas long
ago as the end of the 18th century,
in the works of the British
philosopher andmathe
matician John Michell
and the renowned French scientist
Pierre Simon de Laplace.
Both had reasoned that
heavenly bodies couldbecome
so dense that they would be invisible –
not even the speed of light would be fas
tenough to escape their gravity.
A little more than a century later,
when AlbertEinstein published his general
theory of relativity,
Nobel Prize
some of the solutions to the theory’s
notoriouslydifficult equations described
just such dark stars.
Up until the 1960s, these solutions were
regardedas purely theoretical speculations,
describing ideal situations in which stars and
theirblack holes were perfectly
round and symmetrical.
But nothing in the universe is perfect,
andRoger Penrose was the
first to successfully
find a realistic solution
for all collapsingmatter,
with its dints,
dimples and natural imperfections.
The question of the existence of black
holesresurfaced in 1963,
with the discovery of quasars,
the brightest objects
in the universe.
Let’s GoNoble prize History
For almost a decade,
astronomers had beenpuzzled
by radio rays from
mysterious sources, such as 3C273
in the constellation of Virgo.
The radiation in visible light finally
revealedits true location –
3C273 is so far away that
the rays travel towards
Earth for overa billion years.
If the light source is such a
long way away,
it must have an intensity
equal to the light of several
hundred galaxies,
Nobel Prize ,
It was given the name ‘quasar’.
Astronomers soon found quasars
that were sodistant they had emitted
their radiation in the early
childhood of the universe.
Where does this incredible
radiation comefrom?
There is only one way to
obtain that muchenergy
within the limited
volume of a quasar –
from matter falling into a
massive blackhole.
Noble prize in Physics
Whether black holes could form under realistic
conditions was a question that
puzzled Roger Penrose.
The answer, as he later recalled,
appearedin the
autumn of 1964 during a walk
with a colleague in London,
where Penrose was professorof
mathematics at Birkbeck College.
When they stopped talking for a
moment tocross a side street,
an idea flashed into his mind,
Nobel Prize.
Later that afternoon,
he searched for it inhis memory.
This idea, which he
called trapped surfaces,
was the key he had unconsciously
been searching for,
a crucial mathematical tool needed to
describe a black hole.
A trapped surface forces all
rays to pointtowards a centre,
regardless of whether the
surface curves outwards or inwards.
Using trapped surfaces,
Noble Prize
Penrose was able toprove that a
black hole always hides a singularity,
a boundary where
time and space end.
Its density is infinite and,
as yet, thereis
no theory for how
to approach this strangest
phenomenon in physics.
Black Hole History of Noble Prize
Trapped surfaces became a central
conceptin the completion of
Penrose’s proof of the singularity theorem.
The topological methods he introduced
arenow invaluable in the
study of our curved universe.
Once matter begins to collapse and
a trappedsurface forms,
nothing can stop the
collapse from continuing.
There is no way back, as in the story
toldby physicist and
Nobel Laureate Subrahmanyan
Chandrasekhar,
from his childhood in India.
The story is about dragonflies and
their larva,
which live underwater.
When a larva is ready to
unfold its wings,
it promises it will tell its friends
what life is like on the other
side of the water’ssurface.
Physics Scientist for Nobel Prize
But once the larva passes through the
surfaceand flies away as a dragonfly,
there is no return.
The larvae in the water will never hear
thestory of life on the other side.
Similarly, all matter can only
cross a blackhole’s
event horizon in one direction.
Time then replaces space and
all possiblepaths point inwards,
the flow of time carrying everything towards
an inescapable end at thesingularity.
You will not feel anything
if you fall throughthe
event horizon of a supermassive black hole.
From the outside,
no one can see you fallingin and
your journey towards
the horizon continues forever.
Peering into a black hole is not
possiblewithin the laws of physics;
black holes hide all their secrets
behind their event horizons.
Even though we cannot
see the black hole,
it is possible to establish its Noble Prize
properties by observing
how its colossal gravity directs
the motions of the surrounding stars.
Reinhard Genzel and
Andrea Ghez each leadseparate
research groups that explore the
centre of our galaxy, the Milky Way.
Noble Prize for Researches
Shaped like a flat disc about 100,000
lightyears across,
it consists of gas and dust and
a few hundred billion stars;
one of thesestars is our Sun .
From our vantage point on Earth,
enormous clouds of interstellargas and
dust obscure most of the visible light
coming from the centre of the galaxy.
Infrared telescopes and radio
technology werewhat first allowed astronomers
to see through the galaxy’s disc and
image the stars atthe centre.
Using the orbits of the stars as guides,
Nobel Prize
Genzeland Ghez have produced
the most convincing
evidence yet that there is an invisible
supermassiveobject hiding there.
A black hole is the only possible explanation.
For more than fifty years,
physicists havesuspected that
there may be a black hole
at the centre of the Milky Way.
Ever since quasars were
discovered in theearly 1960s,
physicists reasoned that
supermassive black holes
might be found inside most large
galaxies,
including the Milky Way.
Noble Prize
However, no one can currently explain howthe
galaxies and their black holes,
between a few million and
many billion solar masses,were formed.
One hundred years ago,
the American astronomerHarlow
Shapley was the first to identify
the centre of the Milky Way,
in the directionof the
constellation of Sagittarius.
With later observations astronomers
founda strong
source of radio waves there,
which was given
the name Sagittarius A,
Noble Prize
Towards the end of the 1960s,
it became clearthat Sagittarius
A occupies the centre of the Milky Way,
around which all stars in thegalaxy orbit.
It was not until the
1990s that bigger telescopesand
better equipment allowed more systematic
studies of Sagittarius A.
Reinhard Genzel and
Andrea Ghez each startedprojects
to attempt to see through
the dust clouds to the heart
of the Milky Way.
Along with their research groups,
they developed
and refined their techniques,
building unique instruments and
committing themselves
to long-termresearch.
Only the world’s biggest
telescopes willsuffice for gazing at distant stars –
the bigger the better
is absolutely true in astronomy.
Physics Scientist for Noble Prize
The German astronomer
Reinhard Genzel and
his group initially used NTT,
the New Technology Telescope on
La Silla mountain in Chile, Noble Prize.
They eventually moved their
observations tothe Very Large Telescope facility,
VLT, on Paranal mountain (also in Chile).
With four giant
telescopes twice the size of NTT,
Noble Prize
the VLT has the world’s
biggest monolithic mirrors,
each with a diameter
ofmore than 8 metres.
In the USA,
Andrea Ghez and
her research teamuse the
Keck Observatory,
located on the Hawaiian
mountain of Mauna Kea.
Noble Prize Economist
Its mirrors are almost 10 metres in
diameterand are currently
among the largest in the world.
Each mirror is like a honeycomb,
consistingof 36 hexagonal segments that
can be controlled separately to
better focus the starlight,
Noble Prize.
However big the telescopes,
there is alwaysa limit
to the detail they can resolve
because we live at the bottom of an almost
100-kilometre-deepatmospheric sea.
Large bubbles of air above the telescope,
which are hotter or
colder than their surroundings, Noble Prize
act like lenses and refract the light
on itsway to the telescope’s mirror,
distorting the light waves.
This is why the stars twinkle and
also whytheir images are blurred.
The advent of adaptive optics was crucialin
improving observations.
The telescopes are now equipped with a
thinextra mirror that compensates
for the air’s turbulence and
corrects the distorted image.
For almost thirty years,
Reinhard Genzel and
Andrea Ghez have followed their stars in
the distant stellar jumble at
the centre of ourgalaxy.
They continue to develop and
refine the technology,with more sensitive
digital light sensors and
better adaptive optics, Noble Prize
so that imageresolution has
improved more than a thousandfold.
History of Noble Prize
They are now able to more precisely
determinethe stars’ positions,
following them night by night.
The researchers track some thirty of the
brighteststars in the multitude.
The stars move most rapidly within a
radiusof one light-month from the centre,
inside which they perform a
busy dance like that
of a swarm of bees.
The stars that are outside this area,
on theother hand,
follow their elliptical orbits in a
more orderly manner One star,
called S2 or S-O2,
Nobel Prize
completes anorbit of the
centre of the galaxy
in less than 16 years.
This is an extremely short time,
so the astronomerswere able
to map its entire orbit.
We can compare this to the Sun, Noble Prize
which takesmore than 200 million
years to complete one lap around
the Milky Way’s centre;
dinosaurswere walking the Earth
when we started our current lap.
The agreement between the measurements
ofthe two teams was excellent,
leading to the conclusion that
the black hole at the centre
of our galaxy should be equivalent to
around 4 million solar masses,
packed into a regionthe size of our solar system.
Conclusion
We may soon get a direct look at SagittariusA.
This is next on the list because,
just overa year ago,
the Event Horizon Telescope astronomy
network succeeded in imaging the closest
surroundingsof a supermassive black hole.
Farthest in, in the galaxy known as
Messier87 (M87), Nobel Prize
55 million light years from us,
is a blacker than
black eye surrounded bya ring of fire.
The black core of M87 is gigantic,
more thanone thousand
times heavier than Sagittarius A*.
The colliding black holes
that caused therecently
discovered gravitational waves
were considerably lighter.
Like black holes, gravitational
waves existedonly
as calculations from Einstein’s
general theory of relativity,
before being capturedfor the
first time in the autumn of 2015,
by the LIGO detector in the USA.
Roger Penrose showed
that black holes area
direct consequence of the general
theory of relativity but, Noble Prize
in the infinitely strong
gravity of the singularity,
this theory ceases to apply.
The End
Intensive work is being conducted
in the fieldof theoretical
physics to create a new theory of quantum gravity.
This must unite the two pillars of physics,
the theory of relativity and quantum mechanics,
Nobel Prize
which meet in the extreme
interior of blackholes,
Noble Prize
At the same time, observations are
comingcloser to black holes.
The pioneering work of
Reinhard Genzel
andAndrea Ghez has led the way
for new generations of
precise tests of the
general theory ofrelativity and
its most bizarre predictions.
Most likely, Nobel Prize,
these measurements will
alsobe able to provide
clues for new theoretical insights.
The universe has many secrets
and surprises
left to be discovered.