- 4479 - EUCLID TELESCOPE - will it discover Dark Energy? - Europe's Euclid space telescope may see into the dark universe and may put Einstein's famous theory of general relativity into question. 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.
------------------------ 4479 - EUCLID TELESCOPE - will it discover Dark Energy?
- 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, and 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.
-
- Solving cosmology's greatest mystery, I'm
working on it!. “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.
-
- Whereas 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 Saturday, July 1,2024, 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.
-
- But how exactly is Euclid going to
"reveal" the existence of the invisible universe when it cannot see
and measure it? 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 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.
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 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. 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.
-
- It will take years for the telescope to
gather enough data to answer the big questions. Today 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.
Maybe we will have a surprise when we find out.
-
-
May 23, 2024 EUCLID
TELESCOPE - will it discover Dark
Energy? 4479
------------------------------------------------------------------------------------------
-------- 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” -----------
--------------------- --- Saturday, May 25, 2024
---------------------------------
No comments:
Post a Comment