- 4184 - UNIVERSE NEW VIEW - Europe's Euclid space telescope? Europe's Euclid space telescope will see into the dark universe. Euclid's measurements may put Einstein's famous theory of general relativity into question. The new European space telescope will look for evidence of dark matter and dark energy in the cosmos.
------ 4184 - UNIVERSE NEW VIEW - Europe's Euclid space telescope?
- There is a problem
with our understanding of the universe: It doesn't make sense if we account
only for the matter and energy that we can see, measure or detect.
-
- Albert Einstein's
famous general theory of relativity, which describes the physical 'rules' of
the universe in a series of equations only adds up on cosmic scales if there is
five times as much matter dispersed throughout the cosmos than what we can see
and detect.
-
- This invisible
matter, or “dark matter”, together with another invisible entity, “dark
energy”, form the biggest mystery in cosmology, the study of the origins of the
universe.
-
- While dark matter
pulls stuff together with the force of gravity, the elusive dark energy seems
to be doing the exact opposite, pushing things apart and causing the
acceleration of the expansion of the universe that was first discovered in 1998.
Together, dark energy and dark matter account for a mind-boggling 95% of the
"stuff" in the universe, and we know close to nothing about this
"stuff."
-
- Dark matter is
something that gravity works on in the same way as normal matter, but it
doesn't interact with any light or any anything so we only know it's there by
the effect it has on the movements of galaxies and stars.
- Dark energy is
something we found out about more recently when we discovered that the
expansion of the universe seems to be getting faster with time. That doesn't
make any sense if you think there's just gravity there. It should be slowing
down.
-
- The new European
Euclid telescope, launching on July 1, 2023,
might bring that answer a little closer into view. The spacecraft,
fitted with a 3-foot-11 inch telescope, will also help map the distribution of
dark matter across spacetime in three dimensions for the first time ever.
-
- The telescope,
fitted with sensors capable of detecting visible and infrared light, will join
the famed James Webb Space Telescope at Lagrange Point 2. In this region some
900,000 miles away from Earth, the gravitational forces of the planet and the
sun are equal, keeping the spacecraft in a stable location relative to Earth.
-
- Here, shielded from
the glare of the star at the center of our solar system, Euclid will look into
the depths of the cosmos, 10 billion years back in time, to map the
distribution of galaxies across one third of the sky outside our Milky Way
galaxy. It will take over six years for the $660 million telescope to complete
its survey.
-
- Euclid's images,
which will look quite like the famous Hubble Space Telescope's Deep Field
images, will also allow astronomers to study how the gravity of invisible dark
matter alters the shapes of the galaxies as they appear in those images.
-
- If you've got a
very large clump of matter, any sort of matter, not necessarily dark matter, it
will bend the light rays. Which means
that anything behind that type of matter will look distorted. These distortions, also known as the
gravitational lensing effect, are minuscule, so minuscule in fact, that they
can't be accurately measured by ground-based telescopes due to the blurring
caused by Earth's atmosphere.
-
- The effect is very
tiny, less than 1%. To detect this tiny
effect is very difficult. We need to be very, very precise with our image
quality and measure many, many galaxies to be able to deduce anything.
-
- By using some
rather complicated math, astronomers will be able to use these gravitational
lensing measurements to calculate the amount of dark matter between Euclid and
each distorted galaxy, allowing them to create the first ever 3D map of the
dark matter's distribution in the universe.
-
- Although dark matter
has never been directly observed, scientists are quite certain of its
existence. There is evidence of dark
matter in so many ways that it is quite unlikely that Euclid could find
evidence through measuring the gravitational lensing that it does not exist. Dark matter must exist because there is
simply not enough normal matter to grow galaxy structures, to have them
assemble the way they are.
-
- The existence of
dark energy, on the other hand, is less certain and it's in this area where
Euclid scientists expect the biggest surprises. At stake is the ultimate
validation of Albert Einstein's famous and widely accepted theory of
relativity, which claims to capture what is supposed to be the universal rules
of the behavior of all matter and energy in the universe.
-
- It could be simply
that general relativity doesn't really work at cosmic scale, and therefore dark
energy is not needed. We need dark
energy now if we assume that general relativity works. Dark energy is not
needed to grow the cosmic structures, to grow stars and galaxies.
-
- Many experiments
and observations made at smaller distances have confirmed the theory of general
relativity over the years. If Euclid's measurements were to take this theory
into question, it would be "an absolute discovery" .
-
- Astronomers want to
find evidence for the existence of dark energy in the distribution of galaxies
and galaxy clusters across spacetime. They believe this distribution is not
random, but a reflection of soundwaves that bounced around the ancient
universe.
-
- In the wake of
these soundwaves, regions of denser gas emerged that later gave rise to
galaxies. Astronomers can observe these
patterns in the cosmic microwave background, the remnants of the first light
that spread through the emerging universe in the first hundreds of thousands of
years after the Big Bang and that can still be detected today.
-
- In the cosmic
microwave background, we can see this pattern as it looked in very early
times. With Euclid, we will be able to
measure it much closer to us now in time in the pattern of galaxies in the sky.
We will see this imprint in the scale that galaxies like to cluster, in their
preferred distance separation.
-
- By comparing the
ancient imprints with the newer ones, scientists will be able to see how much
the universe has expanded since its earliest days and what role dark energy may
have played in this process.
-
- Because the dark
energy pushes the universe apart, if there's a lot of dark energy, we'll see that
that scale is much larger than we would have otherwise. For now all models point to the existence of
dark energy that is constant and spread uniformly throughout the cosmos.
-
- Some evidence
suggests that things may not be all that simple. The Hubble constant that
describes the rate of the universe's expansion doesn't appear to be the same in
the nearby observable cosmos as it is in the early universe, a possible sign
that something might not be right with the cosmology models.
-
-
October 11, 2023 UNIVERSE NEW VIEW - Euclid space telescope? 4184
------------------------------------------------------------------------------------------
-------- Comments
appreciated and Pass it on to whomever is interested. ---
--- Some reviews are
at: -------------- http://jdetrick.blogspot.com -----
-- email feedback,
corrections, request for copies or Index of all reviews
--- to: ------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
--------------------- ---
Wednesday, October 11, 2023 ---------------------------------
No comments:
Post a Comment