We present a simple, unified model that can explain two of the brightest, large-scale, diffuse, polarizedradio features in the sky, the North Polar Spur (NPS) and the Fan Region, along with several otherprominent loops. We suggest that they are long, magnetized, and parallel filamentary structures thatsurround the Local arm and/or Local Bubble, in which the Sun is embedded. We show this modelis consistent with the large number of observational studies on these regions, and is able to resolvean apparent contradiction in the literature that suggests the high latitude portion of the NPS isnearby, while lower latitude portions are more distant. Understanding the contributions of this localemission is critical to developing a complete model of the Galactic magnetic field.
Dr. Jennifer West, Research Associate at the Dunlap Institute for Astronomy and Astrophysics, is making a scientific case that two bright structures that are seen on opposite sides of the sky – previously considered to be separate – are actually connected and are made of rope-like filaments. This connection forms what looks like a tunnel around our solar system.
“If we were to look up in the sky,” explains West, “we would see this tunnel-like structure in just about every direction we looked – that is, if we had eyes that could see radio light.”
An expert in magnetism in galaxies and the interstellar medium, West looks forward to the more possible discoveries connected to this research.
“Magnetic fields don’t exist in isolation,” she says. “They all must to connect to each other. So, a next step is to better understand how this local magnetic field connects both to the larger-scale galactic magnetic field, and also to the smaller scale magnetic fields of our sun and Earth.”
(Oct 19, 2021)
The space radiation that comes at us from other stars is called galactic cosmic radiation (GCR). Active areas in the galaxy – like supernovae, black holes, and neutron stars – can strip the electrons from atoms and accelerate the nuclei to almost the speed of light, producing GCR.
On Earth, we have three layers of protection from space radiation. The first is the heliosphere, which helps block GCR from reaching the major planets in the solar system. Additionally, Earth’s magnetic field produces a shield called the magnetosphere, which keeps GCR out away from Earth and low-orbiting satellites like the International Space Station. Finally, the gases of Earth’s atmosphere absorb radiation.
„Voyager 2“ hat die Grenze der Heliosphäre in nur einem Tag passiert, was einen scharfen Übergang zum lokalen interstellaren Medium bedeutet. „Die alte, historische Vorstellung, dass der Sonnenwind sich einfach allmählich reduziert, je weiter man in den interstellaren Raum vordringt, trifft nicht zu“, erläuterte „Voyager“-Forscher Don Gurnett von der Universität von Iowa, Ko-Autor einer der Analysen. „Wir haben mit ‚Voyager 2‘ und vorher mit ‚Voyager 1 gezeigt, dass es dort draußen eine ausgeprägte Grenze gibt.“
Despite encountering the heliopause at different times and locations — the two spacecraft are farther from each other than each are from the sun — some things looked similar. The magnetic field looked pretty much the same on the inside and the outside of the boundary: Somehow, the sun’s magnetic field lines up nearly perfectly with the local galactic field, contrary to expectations. “We could dismiss that as coincidence in one case, but we can’t do that twice,” study coauthor Leonard Burlaga, of NASA’s Goddard Space Flight Center in Greenbelt, Md., said in the news conference.
Here, we report measurements of energetic (>28 keV) charged particles on V2 from the interface region between the heliosheath, dominated by heated solar wind plasma, and the VLISM, expected to contain cold non-solar plasma and the Galactic magnetic field. The number of particles of solar origin began a gradual decrease on 7 August 2018 (118.2 au), while those of Galactic origin (Galactic cosmic rays) increased ~20% in number over a period of a few weeks. An abrupt change occurred on 5 November when V2 was located at 119 au, with a decrease in the number of particles at energies of >28 keV and a corresponding increase in the number of Galactic cosmic rays of energy E > 213 MeV. T
The shape depends, in a complex way, on the relative strengths of the magnetic fields inside and outside of the heliosphere, and the latest measurements are suggestive of a more spherical form.
Nach Jahrzehnten haben sie nun die Grenze der Heliosphäre passiert und sind damit auf dem Weg zu den Sternen.
The word ‘astronomy’ means the direct observations of extra-terrestrial objects. This definition is relevant to photons, neutrinos, and gravitational waves, i.e. massless, neutral and stable particles. But for cosmic ray electrons, protons, and nuclei, the term ‘astronomy’ is used with a certain reservation. Because of the deflections of electrically charged particles in the chaotic interstellar and intergalactic magnetic fields, the information about their original directions pointing to the sites of their production is lost. Instead, on the Earth, we detect an (almost) isotropic flux of cosmic rays contributed by a huge number of galactic and extragalactic sources.