Why JAMES WEBB Is ready to rewrite Cosmic History?
The James Webb Telescope is the most potent and expensive space astronomical observation
instrument created throughout human history. Their mission will be to discover which stars and
galaxies formed at the beginning of the universe, observe the most distant stars' evolution
and behavior, and study potentially habitable exoplanets to find out if there is life in them.
The James Webb has a launch date of December 22, 2021, and if all is well,
it will be the new space telescope that will replace the famous Hubble Space Telescope.
This powerful new telescope will study the universe in infrared radiation,
but What is infrared radiation?
In astronomy, there is something called "Electromagnetic Radiation Spectrum,"
which consists of a scheme where all types of electromagnetic waves that exist are classified;
for example, the light we can see is a type of radiation called "visible light."
There is also another type of radiation that we can not see but that we can feel in the form of
heat. This is "Infrared radiation," there are also radio waves such as
Wi-Fi signals emitted by your phone or TV signals, among many others.
Humans can only perceive a small portion of all the types of electromagnetic waves that exist
with our eyes. The visible light, the rest are invisible to our eyes.
The Hubble Space Telescope, the most powerful telescope to date,
can only observe in the ultraviolet, visible light,
and near-infrared ranges, meaning it has a field of vision much like the human eye.
However, the most distant and ancient events in the universe, such as the birth of the
first stars or the first galaxies, can only be observed in the mid-and far-infrared spectrum.
This is because galaxies move away, and the universe expands.
For this reason, the light from the farthest bodies stretches and
travels towards the red frequencies as they travel through the universe.
In astronomy, "near-infrared" is considered to be infrared waves
of infrared radiation that have a wavelength close to those of visible light,
i.e., 700 nanometers (nm). In contrast, infrared radiation farthest from visible
light is called "Far Infrared," They have a wavelength of up to1 millimeter (mm).
And finally, there is the "Mid-infrared" whose wavelength ranges from 5 to
28 micrometers(μm). 1 micrometer (μm) is equal to 1000 nanometers (nm).
The James Webb telescope is specialized in the latter, in the mid-infrared; it will see
everything that Hubble cannot see. However, the James Webb telescope is not the first telescope
in history to observe in the mid-infrared. SPITZER TELESCOPE
In 2003 NASA put the large Spitzer telescope into operation,
which, like the James Webb, could observe the frequencies of signals in the mid-infrared.
For 16 long years, this telescope made essential contributions to science, such as:
He studied comets and asteroids in our solar system
Thede-covering of a previously unidentified ring around Saturn
The formation of stars and planets The evolution of galaxies
The composition of interstellar dust And, of course, his best-known work,
the detection of seven Earth-sized planets in the TRAPPIST-1 system. (1)
In 2020 the spacecraft stopped working permanently,
but it left us excellent knowledge of the universe.
Although the Spitzer telescope and the James Webb telescope have similarities, in reality,
they both have differences informed. PRIMARY MIRROR
The most significant difference is the primary
mirror. The Spitzer telescope's mirror averages only 8.5 meters in diameter,
and it was even smaller than Hubble's primary lens, which measures 2.4 meters.
In contrast, the primary lens tea of the James Webb measures 6.5 meters!
It is made of Beryllium and covered with a thin layer of gold;
this will give it a perfect reflection with which it can capture the light of very faint objects
such as the disks of dust around stars or the cloud of gas the outskirts of the galaxy.
It also represents an unprecedented increase in range, and we will be able to see objects
billions of times farther away than Spitzer could see and much smaller than Hubble can see.
It will be possible to see the farthest galaxies in the observable universe and study tiny bodies
such as exoplanets from near-Earth star systems that are impossible to see with modern telescopes.
THE PROBLEM WITH INFRARED Observing infrared light waves
has always been a feat for astronomers. It represents one of the biggest engineering and
technology challenges they can face, as doing so requires a somewhat tricky condition to achieve.
That condition is cold. To observe the infrared radiation from space, the telescope must maintain
a shallow temperature below 50 K (-220 °C; -370 °F), which is achieved with refrigerants. However,
the planet's atmosphere emits infrared radiation that interferes with observations,
so it is impossible to obtain good infrared images of the universe from Earth;
the only way is to place a telescope in space.
The Hubble e telescope that is orbiting the Earth at 550 km high maintains a relatively
low-temperature thanks to its thermal insulation system that protects it from solar radiation.
Yet, the heat produced by the telescope itself interferes with infrared observations.
The Spitzer telescope maintained a shallow temperature with the help of
a panel that blocked sunlight and prevented the instruments from releasing infrared radiation.
The James Webb will use a system based on the Spitzer, but instead of a fixed panel,
will use five folding parasols made of a polyimide film, an extremely resistant polymer;
in addition, the parasols will be coated with aluminum membranes on the side
that will point to the Sun and with silicone on the opposite side.
To ensure that the parasols of the telescope are always facing the same direction,
they will be placed at the L2 point of Lagrange.
Lagrange points are regions in space around the Sun associated with a planet where objects
entering can stay because there is a gravitational balance between the Sun and a celestial body. (2)
Each planet has 5 Associated Lagrange points, and they are usually essential
for the fuel-saving of space missions since a ship can stay in those regions with hardly any work.
The L2 point associated with the Earth is located 1.5 million kilometers from
the Earth in the opposite direction to the Sun; this will grant permanent communication
with the telescope and will allow maintaining its parasols pointing at the Sun at all times
so that solar radiation does not interfere with the telescope systems.
All this will ensure that James Webb can observe without interruption 24 hours a day,
keeping its temperature below 50° K and giving us the most impressive images of the universe.
The only problem with placing the telescope in this region is that there is no possibility of
repairing it in case of a failure or breakdown, as happened with the Hubble telescope.
Hubble has located 550 km from Earth. Years after being put into orbit,
different human-crewed missions were carried out to make adjustments
and update the telescope vital for functioning correctly.
The James Webb will be 1.5 million kilometers from the Earth,
more than double the distance to which the moon is. If there is a failure or breakdown, everything
is over. There is no possibility of sending any human-crewed mission to fix it; that is why NASA
engineers are making their maximum effort so that this does not happen. Everything must be perfect.
JAMES WEBB INSTRUMENTS The telescope will be composed of 3 main parts,
the optical lens, and the thermal parasol, of which we have already talked, and finally,
the Integrated Scientific Instruments Module(ISIM).
James Webb's measuring and observation instruments will be contained within the (ISIM),
which is the most critical payload. (3)
This is where the following four instruments were placed:
Near-Infrared Camera (NIRCam) The Near-Infrared Camera
(NIRCam) is a near-infrared radiation detection camera
that will measure infrared wavelengths from 0.6 to 5 micrometers and be James Webb's main imager.
With the NIRCam, we will be able to detect: The first stars and galaxies that formed in the
universe, details in the stars of galaxies near the Milky Way, and the objects in the Kuiper Belt.
In addition, NIRCam will be equipped with coronographs, instruments that
allow astronomers to take pictures of very faint objects around a bright central entity,
such as star systems close to our own, and thus determine if there are planets on them. (4)
Near-Infrared Spectrograph (NIRSpec) The near-infrared spectrograph (NIR Spec)
will be the instrument in charge of analyzing the spectrum of the most distant objects and informing
us about their physical properties, including temperature, mass, and chemical composition.
The atoms and molecules in the celestes' bodies print lines in their light spectrum
uniquely. Each chemical element has a signature like a fingerprint, that is to say, that just by
analyzing the light coming from the celestial bodies, we can know what they are made of.
The NIR Spec will provide us with a wealth of information about exoplanets' physical
and chemical conditions that could have liquid water and possibly extraterrestrial life. (5)
MID-INFRARED INSTRUMENT (MIRI) The mid-infrared instrument (MIRI)
consists of a camera and a spectrograph that sees the light in the mid-infrared region.
MIRI will cover the wavelength range of 5 to 28 micrometers.
Its sensitive detectors will allow it to see red-running light from distant galaxies,
newly formed stars, and faintly visible comets, as well as objects in the Kuiper Belt.
In addition, it will provide wide-field broadband images, that is, the same images that the Hubble
telescope is already capable of taking, but much sharper and brighter, which is why the James Webb
is considered to be the successor to Hubble. (6) FINE GUIDANCE SENSOR / NEAR INFRARED IMAGER
AND SLITLESS SPECTROGRAPH (FGS/NIRISS) The Fine Orientation Sensor (FGS) will keep
James Webb aiming precisely at his targets 24/7 so that he gets high-quality images.
This artifact will be of vital importance since one of the primary missions of James Webb
is to photograph the light of the most dist objects before the universe.
To achieve this, he must remain hundreds of days focused on the same thing without interruptions.
In addition, the FGS/NIRISS near-infrared imager and slitless spectrograph will be used
to investigate the detection of the universe's first light, detect and characterize exoplanets,
and perform spectroscopy of exoplanet transit in stars near and far. (7)
WHY IS THE JAMES WEBB TELESCOPE SO IMPORTANT?
So far, the most powerful space telescope in existence is the Hubble Space Telescope.
Thanks to the Hubble telescope, we discovered the first exoplanets,
a fantastic variety of planetary nebulae and star clusters,
the frequency with which supernovae occur, as well as the immense number of galaxies in the universe.
One of the most impressive images provided by Hubble was Hubble's deep field, an image that was
obtained after Hubble pointed you to a seemingly empty and dark region of the sky for ten days.
The resulting image helped us understand the vastness of the universe,
for at that little point in the seemingly empty sky were hundreds of thousands of entire galaxies,
each with its stars, planets, and perhaps also life.
The new Telescopium James Webb could bring us the subsequent revelation of the universe. We do
not know well what it will be. Could it be that we finally find living beings on other planets?
or maybe we discover the origin of the first galaxy or the first star in the universe?
Some scientists are betting that maybe we will find new planets in our solar system.
The James Webb opens the beginning of a new era of space observatories,
in which we can see what was always hidden from our sight. We will get to see events that
occurred at the beginning of the universe, just 100 million years after the big bang.
And perhaps the true origin of our universe will be revealed to us.