- 4109 - DARK MATTER and DARK ENERGY ? Dark energy and dark matter, constitute some of the biggest and most fascinating questions to exist in astronomy today. Neither phenomena can be seen by human eyes, yet still appear to be holding our universe together.
-------------- 4109 - DARK MATTER and DARK ENERGY?
- The European Space Agency's ambitious
Euclid space telescope is on its way to decoding the secrets of dark matter and
dark energy. On July 3, 2023, the
Euclid telescope sent its first images back to Earth. And while these seminal
portraits are certainly mesmerizing, they also confirm that the space
observatory's instruments are working in tip-top shape.
-
- Euclid's purpose is to map out the dark side
of our universe by analyzing billions of galaxies that reside up to about 10
billion light-years away. This ambitious
map will be in "3D," because it'll include the element of time to
show how those realms evolved in tandem with a maturing universe.
-
- The outstanding first images obtained using
Euclid's visible and near-infrared instruments open a new era to observational
cosmology and statistical astronomy.
They mark the beginning of the quest for the very nature of dark energy.
-
- Euclid launched on July 1 from Cape
Canaveral in Florida. Now floating about a million miles from Earth, it joined
the James Webb Space Telescope on July 28 at what's known as the second
Lagrange point.
-
- Euclid's VIS captures the universe through
the part of the electromagnetic spectrum that's visible to human eyes,
wavelengths between 550 and 900 nanometers.
The range of the close-up to about one quarter the width and height of
the full moon as seen from Earth.
-
- Some highlights of VIS' portraits include
cosmic rays shooting straight across the field, a wealth of unmissable
glittering stars, and most importantly, a few fuzzy blobs. Those blobs are
galaxies Euclid will investigate further while developing a highly detailed map
of our universe, dark energy and all.
-
- NISP, Euclid's Near-Infrared Spectrometer
and Photometer has two roles. First, it can image galaxies in infrared light,
or light invisible to human eyes that falls between about 950 and 2020
nanometers on the electromagnetic spectrum. The James Webb Space Telescope also
taps into such infrared wavelengths, which is why scientists often say it's
unveiling an invisible universe. It quite literally is.
-
- Second, NISP can measure precisely how much
light each galaxy emits to tell us how far away those galaxies are. Before reaching the NISP detector, deep
space light captured by Euclid also passes through some filters. These filters
can do things like measure brightness at a specific infrared wavelength, which
helps with NISP's galactic distance measurements.
-
- Euclid has a device known as a
"grism" that can basically split cosmic light into a full spectrum of
wavelengths before sending the data to NISP.
With this process, scientists can determine how far away a certain
galaxy is, as well as what the galaxy is chemically made of.
-
- Space is constantly expanding outward in
every direction like an unpoppable balloon. But the weird thing is, this
ballooning seems to be happening at speeds scientists can't quite account for
with all the visible stuff in our universe. Thus, something else must be acting
to accelerate the cosmic expansion, "something" dark energy.
-
- Also within the expanding universe, there
seems to be some sort of glue making sure galaxies are held in place and
dictating the way they're arranged. For example, scientists calculate that
intergalactic gas and stars often move around as though there's extra gravity
pulling on them.
-
- Presumably, this is because some sort of
invisible material surrounds the galaxies these objects live in (perhaps like a
halo) and therefore exerts gravitational forces on them. That unseeable
"glue" is known as dark matter.
-
- Dark matter and dark energy aren't
necessarily made up of one, or even two, things. They could be made up of a
bunch of different components. Scientists just use these as bulk terms to
describe gaps in our understanding.
-
- As dark matter and energy interact with
things in space, laying out the distribution and evolution of those things can
tell us where the dark universe fits into the story. Using Euclid to reveal so much about the 95%
of the universe that we currently know so little about.
-
- The fully calibrated Euclid will ultimately
observe billions of galaxies to create the biggest-ever 3D map of the sky. Maybe we can learn more about our dark
universe?
-
-
August 1, 2023 DARK
MATTER and DARK
ENERGY? 4109
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