- 4380 - JAMES WEBB DICOVERIES? The James Webb Space Telescope's targets over the next year include black holes, exomoons, dark energy. These are the programs that will use humanity's most powerful and sensitive space telescope for a collective 5,500 hours between July 2024 and June 2025. This range is known as Cycle 3 of JWST operations.
---------------------------------------- 4380 - JAMES WEBB DICOVERIES?
- James Webb Cycle 3 will build upon the
previous two years of scientific advancements made by this $10 billion dollar
telescope, which began beaming back data in 2022. Some of the JWST's third-year targets
include potential exomoons, or moons that surround exoplanets, exoplanets
themselves in conjunction with their atmospheres, supermassive black holes and
even distant galaxies that existed during the dawn of time.
-
- The JWST will also study large-scale
structures in the universe to reveal details about the accelerating expansion
of the universe and dark energy, the mysterious force that drives such
movement.
-
- One of the teams will be searching for
moons outside the solar system. These are known as extra-solar moons, or,
"exomoons." They hope to find
moons around the exoplanet “Kepler-167e” in particular. This gas giant is
around the size and mass of Jupiter and is located 1,115 light-years from
Earth.
-
- Exomoons have proved an elusive subject for
astronomers because they are hunted using the same light-blocking technique
employed to spot exoplanets around stars. However, this technique is difficult
enough when looking for large worlds beyond Earth. Searching for little exomoons with it is
immensely challenging. Not only would exomoons block far less light than the
exoplanets they orbit would, but they'd also need to be in the right position
at the right time.
-
- An exomoon that's detectable would have to
be orbiting its planet precisely as that planets crosses, or
"transits," the face of its parent star to obscure some light when
viewed from our vantage point in the cosmos. That obstruction would be detected
by scientists' equipment, which would allow them to reverse-calculate that an
exoplanet, or potentially exomoon, gave rise to it.
-
- By focusing on Kepler-167e with the JWST's
Near Infrared Imager and Slitless Spectrograph (NIRISS), they can make the
first undisputed detection of an exomoon.
The JWST's “Cycle 3 GO” projects also include a wealth of investigations
focusing on exoplanets themselves and not just their potential moons.
-
- Among those exoplanet habitability projects
is one called "Constraining the atmosphere of the terrestrial exoplanet
“TOI-4481b." This will use the JWST's Mid-Infrared Instrument (MIRI) for
16 hours to determine if a roughly Jupiter-mass exoplanet, which orbits a star
around half as massive as the sun that sits some 39 light-years away, has been
able to hang on to its atmosphere.
-
- The result could serve as a first step in
understanding the habitability of rocky planets and establishing whether M-type
stars, also known as red dwarfs, have terrestrial planets with significant
atmospheres. This is important in the search for life beyond Earth because red
dwarfs are the most common stars in the Milky Way.
-
- Seeking out supermassive black holes. Astronomers widely believe the majority of
our universe's large galaxies have supermassive black holes in their hearts
with masses as great as millions, or even billions, of suns. Some of these
supermassive black holes are actively swallowing gas and dust that surrounds
them in disks of matter called “accretion disks”.
-
- These monster black holes' gravitational
influences are thought to heat the material in those accretion disks, causing
them to emit bright radiation across the electromagnetic spectrum and create
regions called “Active Galactic Nuclei” (AGN). Any matter that isn't swallowed
by the black hole can be channeled to its poles,where it is blasted out as jets
of particles traveling at speeds approaching light. When that happens, the
phenomenon is a called a “quasar”.
-
The violent conditions of
these events make AGNs and quasars the brightest objects in the universe, often
luminous enough to outshine the combined light of every star in the galaxies
around them. Our theoretical understanding of supermassive black holes has
burgeoned since the Event Horizon Telescope (EHT) revealed the first image of a
black hole, the supermassive black hole at the heart of the galaxy Messier 87
(M87), in 2019.
-
- The JWST Cycle 3 supermassive black hole
observation programs include the investigation of quasars in the early universe
and the nature of the first black holes. Scientists hope to understand how
those black holes may have influenced the growth of galaxies over billions of
years.
-
- The JWST's observations of supermassive
black holes in the early universe could also reveal how these cosmic titans
grew to the tremendous masses scientists observe, before the universe was even
1 billion years old. Such a question can be answered by using MIRI to
investigate if a giant molecular cloud that existed around 13.2 billion years
ago could have directly collapsed, birthing a "heavy black hole seed"
that would account for a rapid growth mechanism.
-
- One of the primary roles of the JWST is
investigating objects in the early universe. The powerful space telescope has
this capacity because the expansion of the universe stretches wavelengths of
light from distant objects as this light travels toward us, moving the
wavelengths toward the "red end" of the electromagnetic spectrum.
-
- The longer that light has traveled to reach
us, the more redshifted the light has become. This means light that has been
traveling for around 12 billion years is extremely redshifted, all the way into
the infrared region of the electromagnetic spectrum and outside the visible
range we can see with the unaided eye.
-
- Effectively, infrared light is invisible to
us. The JWST, however, is capable of observing this infrared light and thus
helps to investigate the first stars and earliest galaxies, something it will
continue to do in 2025 with several Cycle 3 GO projects.
-
- How is dark energy expanding the cosmos at
an accelerating rate, which in turn helps with investigations regarding the
universe's evolution. The epoch of
reionization occurred around 500 million years after the Big Bang.
-
- During this period, neutral atoms of
hydrogen populating the cosmos were ionized by radiation that stripped away
their electrons and left them as ionized hydrogen, or hydrogen ions. Studying
high-redshift galaxies can reveal more about this crucial stage in cosmic
evolution, including how the first galaxies acted as the source of this
ionizing radiation.
-
- Between 2024 and 2025, astronomers will
also train telescopes on distant stars to better understand stellar physics and
populations, as well as examine the gas that exists between stars that can
become the building blocks of the next generation of stars and planets.
-
- Though the JWST was designed with the study
of distant objects in mind, Cycle 3 will also see the observatory used to study
bodies within our own solar system. These will include hunting for the source
of gas plumes coming from Saturn's moon Enceladus, investigating the dynamics
of the Uranus' rings and characterizing icy objects that exist in the Kuiper
Belt at the very edge of the solar system.
-
-
March 7, 2024 JAMES
WEBB DICOVERIES? 4376
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--------------------- --- Thursday, March 7, 2024
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