I discovered that a mysterious print called "dark energy" is created
up to 68% of the total energy content of the cosmos, but not yet
know a lot more about it. The study of the nature of dark energy is one of
Main reasons why NASA builds the Wide Field Infrared Survey Telescope
(WFIRST), a space telescope whose measurements help to illuminate the darkness
Energy puzzle. With a better understanding of dark energy, we become one
Better sense of the past and future development of the universe.
Expand the cosmos
By the 20th century, most were humans
believed that the universe was static and remained essentially unchanged
in all eternity. As Einstein developed his general theory of relativity
In 1915 he described how gravity affects the structure of space-time
confused to find that the theory indicated that the cosmos must either expand or expand
Contract. He made changes to preserve a static universe and added something to it
called the "cosmological constant," though there was no evidence
it actually existed. This mysterious force was supposed to counteract gravity
to keep everything in its place.
However, when the 1920s became one
Nearby, the astronomer Georges Lemaitre and then Edwin Hubble startled
Discovery that, with very few exceptions, galaxies are running away from everyone
other. The universe was anything but static – it shot out.
So, if we imagine rewinding this extension, there must have been one
Time when everything in the universe was almost unbelievably hot and close
Scientists have discovered that a mysterious pressure called "dark energy" accounts for about 68 percent of the cosmic's total energy content, but so far we do not know much about it. Exploring the nature of dark energy is one of the main reasons why NASA is building the Wide Field Infrared Survey Telescope (WFIRST), a space telescope whose measurements will help illuminate the dark energy puzzle. With a better understanding of dark energy, we can better understand the past and future evolution of the universe.
End of the universe: fire or ice?
The big bang theory describes the
Expansion and evolution of the universe starting from this initial superhardness
State. Scientists suspected that gravity might slow down
This expansion can even be reversed completely. If the universe had enough matter
In this case, gravity would overcome the expansion and collapse the universe
fiery "Big Crunch".
If not, the expansion would never end –
Galaxies would continue to grow until they pass the edge of the river
observable universe. Our distant descendants may not be aware of
Existence of other galaxies because they are too far away to be visible.
Much of modern astronomy could one day become a legend like that
The universe is gradually turning into an icy black.
The universe does not just expand – it accelerates
Astronomers have measured the rate of
Extension by use of ground telescopes for investigation of supernova nearby
Explosions. The mystery escalated in 1998 with the Hubble Space Telescope
Observations from more distant supernovae helped to show that the universe is actually
expanded more slowly in the past than today. The expansion of
The universe does not slow down by gravity, as everyone thought. It accelerates
Fast forward to today. While we still do not
know what exactly causes the acceleration, it was given a name – dark
Energy. This mysterious pressure remained undetected for so long because it was
is so weak that gravity makes it on the scale of people, planets and even overwhelmed
the galaxy. It is present in the room you are reading
Body, but gravity counteracts that, so you do not fly out of the seat. It is
it is only on an intergalactic scale that this dark energy becomes perceptible and acts like
a kind of weak resistance to gravity.
Is dark energy?
What exactly is dark energy? More is unknown than known, but theoreticians are
chase down a few possible explanations. Cosmic acceleration could be
caused by a new energy component that would require some adjustments
Einstein's theory of gravitation – perhaps the cosmological constant, the
Einstein called his biggest mistake, it's real.
Alternatively, Einstein's theory of
Gravity can collapse on cosmological scales. If that's the case, that's the theory
must be replaced by a new one that involves the cosmic
We have observed acceleration. The theorists still do not know what's right
Explanation is, but WFIRST will help us find out.
Enlightening Dark Energy
Earlier missions have collected some
Hints, but so far they have not delivered results that favor a strong one
Explanation about another. With the same resolution as Hubble's cameras, but a
WFIRST creates a 100 times wider field of view that has never been seen before
great pictures of the universe. The new mission will spur exploration
The secret of dark energy in a way that other telescopes can not image
Matter is structured and distributed throughout the cosmos, and also through
Measurement of a large number of distant supernovae. The results will show how
Dark energy works throughout the universe and if and how it has changed
The mission will use three survey methods
look for an explanation of the dark energy. The spectroscopic height ratio
The survey will measure exact distances and positions of millions of galaxies
using a standard ruler technique. Measuring how the distribution of
Galaxies vary with distance and give us an insight into the evolution of darkness
Energy over time. This study will connect the distances of the galaxies with the
Echoes of sound waves shortly after the Big Bang and will test Einstein's theory
of gravity over the age of the universe.
The High Latitude Imaging Survey will
Measure the shapes and distances of a variety of galaxies and galaxy clusters.
The immense gravity of massive objects distorts space-time and leads to greater distance
Galaxies appear distorted. Observation of the degree of distortion allowed
Scientists conclude the distribution of mass throughout the cosmos. These
Includes all the matter we can see directly, like planets and stars
as dark matter
– another dark cosmic mystery, visible only through its gravity
Effects on normal matter. This survey provides an independent measurement
the growth of the large-scale structure in the universe and how dark energy has
influences the cosmos.
WFIRST will also conduct a survey
Type of exploding star that builds on the observations that led to the discovery
the accelerated expansion. Type Ia supernovae occur when a white dwarf star
exploded. Type Ia supernovae generally have the same absolute brightness at their peak, producing them
so-called "standard candles". That is, astronomers can determine
how far away they are, seeing how bright they look from the earth – and the
The farther they are, the darker they appear. Astronomers will also deal with the particular
Wavelengths of light coming from the supernovae to find out how fast dying takes place
Stars move away from us. By combining distances with brightness
Measurements will see scientists how dark energy has evolved over time
Comparison with the two high-level surveys.
"The WFIRST mission is unique in
Combination of these three methods. It will lead to a very robust and rich
Interpretation of the effects of dark energy and allows us to make one
definitive statement about the nature of dark energy, "said Olivier Doré, a researcher
Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, and
Team leader planning the first two survey methods with WFIRST.
Discover how dark energy has affected itself
The expansion of the universe in the past will shed light on what it will look like
influence the expansion in the future. If it accelerates further
The expansion of the universe could cause us to experience a "big rift".
In this scenario, dark energy would eventually become dominant
fundamental forces that cause everything that is currently held together –
Galaxies, planets, humans – to break apart. The exploration of dark energy will enable us
to investigate and possibly even foresee the fate of the universe.
More information about WFIRST can be found at:
News media contact
Jet Propulsion Laboratory, Pasadena, CA.
Written by Ashley Balzer
Goddard Space Flight Center of NASA, Greenbelt, Md.