The most important discoveries ever made by space telescopes
During the last decades, and after the revolution brought by the general relativity theory,
many space telescopes were launched.
All of them have a precise goal, and there is always a huge team of physics researchers,
engineers, astronomers, chemists, and opticians, behind a good space telescope.
Perhaps the most important reason why is so important to have space telescopes is overcoming
the atmosphere barrier.
The atmosphere acts like a barrier in some ranges of wavelength, meaning that the light
coming from objects in the universe is filtered by our atmosphere.
The same precious atmosphere that gives us oxygen to breathe, is the same that goes against
us when it comes to observations of the universe.
In this video, we present to you the most important discoveries ever made by space telescopes.
Three, two, one, go!
We'd like to start with one of the most beautiful pictures we have of the Cassiopea A supernova.
I mean, look at it: isn't it amazing?
This picture was taken by the Chandra X-ray space telescope.
It is a telescope specially designed to detect X-ray emissions from very hot regions of the
Universe such as exploded stars, clusters of galaxies, and matter around black holes.
Because X-rays are absorbed by Earth's atmosphere, Chandra must orbit above it, up to an altitude
of 139,000 km (86,500 mi) in space.
Speaking of Cassiopea A, one can notice the blue, the violet, the red colour.
The spherical shape.
Everything is fascinating and, even if it seems a calm environment, that is actually
an image of material going at supersonic speeds.
This is actually what astronomers call supernova remnant, which is the bloom of gas left over
after a massive star went supernova some 340 years ago.
It reveals a star turned inside out!
While massive stars fuse the heaviest elements in their cores and lighter elements in surrounding,
onion-like layers, the Cassiopeia A explosion had flung clumps of iron to the outermost
regions.
The find suggests the star’s contents mixed together right before or after its core collapsed
(or both).
The existence of such supernova remnant was already known to astronomers, but in 1999
the Chandra Space Telescope identified a hot point source near the centre of the nebula
that has been identified as a black hole or neutron star.
Speaking of black holes, With Chandra and XMM Newton space telescopes, astronomers could
estimate black hole spin for the first time.
In fact, by looking at the X rays emissions from black holes, astronomers can see how
close the gas comes to the event horizon.
And, roughly speaking, the closer it gets, the faster the black hole is spinning.
Another important discovery made by the Chandra X-ray observatory was the one regarding planet
habitability.
For example, if a planet receives a lot of X rays from its host star, it is plausible
that there's no life on it.
Chandra's observations revealed for example that high energy radiation irradiates the
three Earth-Size planes in Trappist-1 system, and has probably long ago stripped them of
their atmospheres.
Same happens for proxima centauri.This makes them hostile planets.
The discoveries made by Chandra concerned the X-ray part of the electromagnetic spectrum,
but of course, we launched so many other space telescopes which are sensitive to other parts
of it.
For example, the so-called Spitzer space telescope was thought and built in order to observe
infrared wavelengths.
One of the most important discoveries carried out by Spitzer regarded Saturn and its rings.
In 2009, it spotted a giant ring of dust and ice particles.
This ring was previously unknown to the scientific community.
And it isn't visible to human eyes, i.e. we can't observe it in the visible domain, because
it is composed of tiny particles that reflect very little visible light from the sun.
But it is warm enough to emit some heat in the form of infrared light, so Spitzer could
see it!
Spitzer also brought great news concerning black holes in distant galaxies.
Black holes are actually black, in the sense that we can't see them.
But when material falls into it, it can be heated up and shine.
And the radiation they emit is mostly infrared.
So what researchers did, is to use Spitzer to look at some of the farthest, earliest
supermassive black holes in galaxies.
What they found was almost unbelievable!
For a bunch of systems they studied, there was almost no dust in galaxy centres.
This lack of dust meant that they had spotted supermassive black holes in the very early
universe, where there weren't many heavy elements to aggregate and form dust.
It was like having found the rest of the ancestors of all black holes, the Adam and Eva of all
black holes!
This find helped them understand how black holes and galaxies grow and evolve.
Thank you, Spitzer!
And now, ladies and gentlemen, the moment you all have been waiting for has come!
We are going to talk about some of the most important discoveries of one of the most important
space telescopes ever built!
The Hubble space telescope!
Since its 1990 launch, Hubble Space Telescope has been dazzling the world with images of
space and a deeper understanding of how the universe works.
Compared to the vast 8-10m telescopes built on the ground, with even larger ones planned
in the future, the 2.4m Hubble mirror is relatively average for modern-day research telescopes,
and with optics that are approaching their third decade of use.
However, it consistently outperforms many of the most advanced ground-based telescopes
and is still considered the pinnacle of optical and ultraviolet astronomy, with demand for
its use in research greatly exceeding the available observing time each year.
Hubble told us that the age of the Universe is something like 13.8 billion years.
For comparison, the Earth is one-third younger.
Hubble also discovered that Pluto, the dwarf planet in our solar system, has two moons
orbiting around it: they were called Nix and Hydra, and with Charon, they form Pluto's
moon system.
Nix was imaged along with Pluto and its other moons by the New Horizons spacecraft as it
flew by the Pluto system in July 2015.
Images from the New Horizons spacecraft reveal a large reddish area on Nix that is likely
an impact crater.
Hubble also helped us to create a 3D map of the dark matter, and therefore to better understand
the universe we are living in.
Dark matter is an invisible form of matter that makes up most of the universe’s mass
and creates its underlying structure.
Dark matter’s gravity drives normal matter (gas and dust) to collect and build up into
stars and galaxies.
Although astronomers cannot see dark matter, they can detect its influence by observing
how the gravity of massive galaxy clusters, which contain dark matter, bends and distorts
the light of more-distant galaxies located behind the cluster.
This phenomenon is called gravitational lensing.
Hubble’s uniquely sharp vision allowed astronomers to map the distribution of dark matter in
space using gravitational lensing.
Large galaxy clusters contain both dark matter and normal matter.
By observing the areas around massive clusters of galaxies astronomers can identify warped
background galaxies and reverse-engineer their distortions to reveal where the densest concentrations
of matter lie.
The interesting thing here is that the universe appears to have five times more dark matter
than previously thought.
Gravitational lensing:
Do you have any idea how expensive it was?
Hubble space telescopes' original building costs of more than US $2 billion are exceeded
only by the new James Webb Space Telescope, and the total running costs of Hubble have
far exceeded US $10 billion.
Last but not least, we would like to spend some words about Cheops space telescope.
Cheops is ESA's CHaracterising ExOPlanet Satellite.
It is the first mission dedicated to studying bright, nearby stars that are already known
to host exoplanets, in order to make high-precision observations of the planet's size as it passes
in front of its host star.
It will focus on planets in the super-Earth to Neptune size range, with its data enabling
the bulk density of the planets to be derived – a first-step characterisation towards
understanding these alien worlds.
It was launched in December 2019, and since then it amazed us with brand discoveries that
go further than we ever expected.
It found incredible unique planetary systems.
For example, in January 2021 it detected six planets orbiting the star TOI-178.
Actually, at first, they spotted just five of them.
But scientists noticed that maybe there was something more.
The system appeared to be in harmony.
The team said the theory implied that there could be an additional planet in this harmony.
To check if their theory was, in fact, true, the team scheduled yet another observation
with CHEOPS, at the exact time that this missing planet would pass by – if it existed.
A few days later, the data clearly indicated the presence of the additional planet and
thus confirmed that there were indeed six planets in the TOI-178 system.
Cheops is a really recent mission, and this means that we will hear a lot about its new
discoveries in the upcoming years.
It is one of the first space telescopes completely dedicated to finding f exoplanets.
In January 2022, it revealed a rugby ball-shaped exoplanet!
But how is it possible for a planet to have such a shape?
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We can understand it by thinking about tides.
On coasts, tides determine the rhythm of events.
If there's high tide, the way out to sea is cleared for boats.
Instead, at low tide, boats remain on the land.
On Earth, the tides are mainly generated by the moon, but there are places in the universe
where tides are much more extreme.
This is exactly the case of the planet discovered by CHEOPS, WASP 103b.
The planet orbits its star in just one day and is deformed by the strong tidal forces
so drastically, that its appearance resembles a rugby ball.
This insane planet is located in the Hercules constellation, and it is huge: it's almost
twice the size of Jupiter, and it's 1.5 times more massive.
It orbits closer to its star than the Earth does with the sun.
This is why tides are extremely pronounced.
However, measurements of its shape and tide could be inaccurate.
That's why future observations with CHEOPS again and maybe the James Webb Space Telescope
will be needed to decipher the details of the tidal deformation and internal structure
of WASP-103b and comparable exoplanets.
As you can see, the advent of space telescopes extended our knowledge of the universe and
now our horizons are wider than ever!
As technology improves, we will find more and more amazing discoveries, it's just a
matter of time!
Piece after piece, we are trying to complete the puzzle of the entire universe.
The question is: will we ever be able to complete it?
"This video ends here!
Thanks for watching everyone!
What was your favourite discovery?
Let us know in the comments below, be sure to subscribe, and I'll see you next time on
the channel!"