Why is dark energy so mysterious?īecause we can't measure it directly, we don't even know what it is made of, then formulating experiments to detect it and study its very nature is really challenging. Yet, the current state of the expansion is not constant in time, instead is increasing thus this growing rate in the expansion has to be driven by a different factor, something that wasn't predominantly acting during the early stages of the Universe or at times where galaxies formed. Well, our cosmological model predicts an expanding universe, and as a consequence, the existence of an event that we call Hot Big Bang. How do we know the expansion driven by dark energy isn't just connected to the Big Bang? Without it, the expansion would slow down, and eventually, the Universe would have imploded, shrinking the distance between observed galaxies in the large-scale structure. The latter is necessary to provide a plausible explanation for the current trend in the Universe's expansion. In 1999, the physicist Michael Turner named that hypothetical ingredient of the cosmological budget: dark energy. However, we do know the properties of the ingredient that causes this effect: it has to be a substance or fluid that overcomes the attractive nature of gravity, and it has to be diluted and spread in all space-time. Although all our cosmological observations back up this phenomenon, we still don't have an explanation for this trend in the expansion. This process has been occurring for the last 5,000 million years, and it causes galaxies to recede from others. Why is dark energy a necessary part of the universe?Ībout 25 years ago, it was established that the Universe is expanding, and such expansion is speeding up with time. “Thin jets underlie the solar wind: Solar Orbiter images reveal widespread magnetic plasma jets at the roots of the solar wind” by Ignacio Ugarte-Urra and Yi-Ming Wang, 24 August 2023, Science.Luz Ángela García is a cosmology postdoctoral researcher at Universidad ECCI in Bogotá, Colombia. “Picoflare jets power the solar wind emerging from a coronal hole on the Sun” by L. In a related Perspective, Ignacio Ugarte-Urra and Yi-Ming Wang discuss the study and its findings in greater detail.įor more on this discovery, see Solar Orbiter Discovers Tiny Jets That Could Power the Solar Wind. Based on their calculations, they suggest that plasma outflows from these numerous, frequent picoflare jets, channeled along the open magnetic field lines of coronal holes, might supply a considerable amount of mass and energy to the solar wind throughout the solar cycle. Due to their relatively low kinetic energies, Chitta and his colleagues named these structures picoflare jets. Their energy appears to be derived from magnetic reconnection. These widespread yet faint jets, only a few hundred kilometers across, were seen to last between 20 to 100 seconds, achieving speeds of approximately 100 kilometers per second. Credit: ESA & NASA/Solar Orbiter/EUI Team acknowledgment: Lakshmi Pradeep Chitta, Max Planck Institute for Solar System Research Characteristics of Picoflare Jets The circle indicates the size of the Earth for scale. Each one expels charged particles, known as plasma, into space. They show up as little flashes of bright light across the image. Subsequent analysis revealed many tiny jets being released during the observation. It shows a ‘coronal hole’ near the Sun’s south pole. This movie was created from observations taken by the ESA/ NASA Solar Orbiter spacecraft on March 30, 2022, between 04:30 and 04:55 UTC, and was previously released last year. This wind, a continuous stream of charged particles emanating from the Sun’s corona, is a significant element of space weather inside the heliosphere. They propose that these picoflare jets might supply energy and plasma to the solar wind. The researchers behind the study have termed these jets as “picoflare” jets. Images from the Solar Orbiter revealed small “picoflare” jets within a coronal hole on the Sun, which might supply energy to the solar wind, enhancing our understanding of space weather origins.Įxtreme ultraviolet images of the Sun captured by the Solar Orbiter spacecraft have unveiled many small-scale jets present within a coronal hole. Credit: ESA & NASA/Solar Orbiter/EUI Team acknowledgment: Lakshmi Pradeep Chitta, Max Planck Institute for Solar System Research, CC BY-SA 3.0 IGO The images are ‘negatives’ meaning that although the jets are displayed as dark, they are bright flashes against the solar surface. They show up as dark streaks across the solar surface in this mosaic. The images come from the ESA/NASA Solar Orbiter spacecraft. This mosaic of images shows a multitude of tiny jets of material escaping from the Sun’s outer atmosphere.
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