by The gravity pulls us to earth, a lesson that you learn visceral in the first case. Isaac Newton described gravity as a universal attractive force that holds the moon around the earth in orbit, the planets in the orbit around the sun and the sun in the orbit around the middle of our galaxy.
In the nineties, astronomers made the amazing discovery that the expansion of the universe has accelerated in the past 5 billion years, which implies that gravity can both press and pull.
Einstein’s theory of general relativity explains gravity as a result of a curved space -time, where it enables both attraction and rejection. However, producing gravitational resignation requires a new form of energy with exotic physical properties, which is often referred to as “dark energy”.
New results of a large survey by the universe, which was announced in March 2025, question the conventional image of dark energy.
Dark energy and cosmic expansion
The simplest explanation for the cosmic acceleration takes out an energy form that apparently fills the empty space and remains constant over time, instead of when the universe extends.
In fact, quantum mechanics predicts that the “empty” space is filled with particles that flicker briefly in and out of existence. At first glance, this effect seems to explain a constant dark energy, but no simple estimates of the size of the effect will match actual observations. Nevertheless, constant dark energy is a simple assumption that has proven to be successful in order to explain many cosmological measurements.
Today’s cosmological model of today contains this type of constant dark energy. It also contains atoms and dark matter that exert the attractive gravity that dismisses the rejection of the Dark Energy.
New dark energy measurements
The new measurements from the spectroscopic instrument of dark energy or cooperation with which we are connected represent the sharpest challenge for this standard model so far.
Compared to the constant predictions of the dark energy, the new DESI measurements indicate that the universe expanded a little faster a few billion years ago – 1% to 3% – before it relaxed to the expansion rate predicted today. An explanation for this temporary speed is that the “impairment” of the dark energy – a combination of energy and pressure, which determines its repulsive effect – was higher in the past. The suspension then decreased when the universe continued to expand.
Astronomers can measure the history of the universe from our viewpoint in the present because light moves at finite speed. So we see distant objects like in the past. The cosmic expansion extends over the wavelength of light – a phenomenon known as red shift. Precise measurement of the light of an object can recognize the size of the universe at the time of the outline.
The new DESI results are based on measuring the red shifts of more than 14 million galaxies and create a three-dimensional map that includes 12 billion years of cosmic history. In order to determine the distances that moved the light on this map, Desi measured a subtle feature that was impressed by acoustic waves when the cluster formation of these galaxies that traveled through the early universe.
An exciting result
The evidence of DESI for the development of dark energy is based on the combination of its own removal and the red shift measurements with other measurements of the average matter density in the universe. The higher the density of matter, the stronger it can draw against the expansive pressure from Dark Energy. The measurement measurements come from the Planck Space Mission guided by Europe, which mapped the structure in the cosmic microwave background.
The combination of DESI and Planck data is favors dark energy instead of constant dark energy with a statistical significance of 3.1 standard deviations. This result only has a 1 of 500 chance to be able to occur randomly.
Despite the long probability, physicists consider such a finding as a solid but not overwhelming evidence, partly because even the most careful experimenters may underestimate uncertainties in their measurements.
In order to strengthen the statistical case, Desi scientists added measurements to cosmic distances through the cooperation of the Dark Energy Survey, which used a different measurement technology based on the brightness of light from Supernova explosions.
The combination of Supernovae from Desi, Planck and Dark Energy Supernovae favors the developing dark energy model by 40,000 to 1. However, other supernova surveys provide results that match more with constant dark energy, so that most cosmologists are not yet willing to give up the cosmological standard model.
Even if Desis stop results, you cannot say what dark energy is. But you can provide much more gain information than cosmologists beforehand.
The DESI-based model implies that dark energy has surprisingly quickly changed its properties. The dark energy lost its repulsive strength at about the same time, in which it became the dominant form of energy in the cosmos.
This model is extrapolated in the past and also implies that the dark energy once had an extraordinary pushing, on a level that cannot explain a simple theory of a dark energy field. If future data sharpen these measurements, the results could refer us in a strange new direction – perhaps even the gravity of gravity.
In the model that fits the DESI data, the density of the dark energy increases and then decreases, which are displayed as a blue curve, instead of remaining constant, as in the standard cosmological model, which is displayed by the horizontal dotted line. In both cases, the density of atoms and dark matter densifies while the universe extends, and today is only about half of the dark energy. The repulsive effect of the dark energy began to cross the attractive effect of matter when the universe was about 8 billion years old, and “starts acceleration”. David Weinberg
An ambitious experiment
Desi is an extremely ambitious undertaking and an example of “great science” at its best. The instrument itself is mounted on the 4-meter Mayall telescope on Kitt Peak National Observatory. 5,000 optical fibers are used, which are mounted on tiny robot positioners who manage the light of individual galaxies to scientific instruments that analyze this light and record the data for measuring red shifts.
Every 15 minutes the telescope changes to a new area of the sky, and the robots move the fibers to 5,000 new galaxy locations. After five years of construction and construction, Desi has been continuously operated since 2021.
A close-up of the DESI focus level, which shows some of the 5,000 fiber positioners. The white spots in the bluish circles are the optical fibers that lead the light collected by removed galaxies to the spectrographs about 40 meters away. Dr. Claire Poppett, Desi Cooperation
Desi under the direction of the Lawrence Berkeley National Laboratory of the Department of Energy is a collaboration of over 900 scientists at 70 institutions around the world. At our university alone, more than 20 faculties, students, postdocs and research employees have worked on DESI in the past ten years.
This work includes contributions to the structure and installation of spectrographs that measure the properties of light as well as software for recording data, leading instrument operations, observation and troubleshooting in the telescope on the telescope, to observe galaxy and quasar surveys, test catalogs for statistical analyzes that test measurement techniques that test with computer activities.
If the evidence of the development of the dark energy and despite our instinctive caution, we believe that it has a good chance of doing this to a list of remarkable discoveries of the 21st century that are achieved with large US national investments.
These discoveries include the first detection of gravitational waves through the laser interferometer gravitational wave wave observatory, ligo and the spectacular measurements of galaxies and exoplanet atmospheres of the James WebB world dream telescope of NASA.
These successes show how the support of science can achieve by US taxpayers and committed, creative researchers all over the world.
This article will be released from the conversation, a non -profit, independent news organization that brings you facts and trustworthy analyzes to help you understand our complex world. It was written by: David Weinberg, The Ohio State University; Ashley Ross, The Ohio State University; Klaus Honscheid, The Ohio State Universityand Paul Martini, The Ohio
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David Weinberg receives funds from the National Science Foundation and NASA, which supports its dark energy research.
Ashley Ross receives funds from Lawrence Berkeley National Lab to support his work on Desi and NASA to support work on related experiments.
Klaus Honscheid receives funds from the Energy Ministry.
Paul Martini receives funds from the Ministry of Energy.
