Archiv: Radiowellen / radio waves (elektromagnetische Strahlung / electromagnetic radiation)


21.10.2023 - 20:51 [ National Aeronautics and Space Administration ]

NASA’s Laser Communications Relay: A Year of Experimentation

(Jun 28, 2023)

The Laser Communications Relay Demonstration (LCRD) uses infrared light, or invisible lasers, to transmit and receive signals rather than radio wave systems conventionally used on spacecraft. Infrared light’s tight wavelengths allow space missions to pack significantly more data – 10 to 100 times more – into a single transmission. More data means more discoveries.

Now, at the halfway point in its experimentation phase, LCRD has shown laser communications’ significant advantages over traditional radio wave systems.

01.07.2023 - 17:20 [ Nature.com ]

Giant gravitational waves: why scientists are so excited

On 29 June, four separate teams of scientists made an announcement1–4 that promises to shake up astrophysics: they had seen strong hints of very long gravitational waves warping the Galaxy.

Gravitational waves are ripples in the fabric of space-time that are generated when large masses accelerate. They were first detected in 2015, but the latest evidence hints at ‘monster’ ripples with wavelengths of 0.3 parsecs (1 light year) or more; the waves detected until now have wavelengths of tens to hundreds of kilometres.

Here Nature reports what these monster gravitational waves could mean for our understanding of the cosmos, and how the field could evolve.

01.07.2023 - 17:05 [ New York Times ]

The Cosmos Is Thrumming With Gravitational Waves, Astronomers Find

(June 28, 2023)

The scientists strongly suspect that these gravitational waves are the collective echo of pairs of supermassive black holes — thousands of them, some as massive as a billion suns, sitting at the hearts of ancient galaxies up to 10 billion light-years away — as they slowly merge and generate ripples in space-time.

“I like to think of it as a choir, or an orchestra,” said Xavier Siemens, a physicist at Oregon State University who is part of the North American Nanohertz Observatory for Gravitational Waves, or NANOGrav, collaboration, which led the effort. Each pair of supermassive black holes is generating a different note, Dr. Siemens said, “and what we’re receiving is the sum of all those signals at once.”

01.07.2023 - 16:50 [ Institute of Physics - IOP.org ]

Searching for the Nano-Hertz Stochastic Gravitational Wave Background with the Chinese Pulsar Timing Array Data Release I

(Published 29 June 2023)

Observing and timing a group of millisecond pulsars with high rotational stability enables the direct detection of gravitational waves (GWs). The GW signals can be identified from the spatial correlations encoded in the times-of-arrival of widely spaced pulsar-pairs. The Chinese Pulsar Timing Array (CPTA) is a collaboration aiming at the direct GW detection with observations carried out using Chinese radio telescopes. This short article serves as a „table of contents“ for a forthcoming series of papers related to the CPTA Data Release 1 (CPTA DR1) which uses observations from the Five-hundred-meter Aperture Spherical radio Telescope. (…)

A Pulsar Timing Array (PTA; Foster & Backer 1990) is an array of pulsars, which are regularly observed. The times-of-arrival (TOAs) are measured for pulses that we see beams of electromagnetic waves emitted by the pulsars sweeping over the Earth. As the directions of the radiation beam and the pulsar rotational axis do not coincide, we observe this radiation as regular pulses synchronized to the pulsar rotation (Gold 1969).

25.10.2021 - 19:22 [ arxiv.org ]

A Unified Model for the Fan Region and the North Polar Spur: A bundle of filaments in the Local Galaxy

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.

25.10.2021 - 19:18 [ Dunlap Institute for Astronomy & Astrophysics, University of Toronto ]

Dunlap Astronomer discovers we may be surrounded by tunnel-like structure

(Oct.14, 2021)

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.”

25.10.2021 - 19:10 [ SciTechdaily.com ]

A Vast “Magnetic Tunnel” May Surround Earth and Our Entire Solar System

(today)

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.”

17.04.2021 - 04:46 [ CNN ]

Giant radio pulses and X-ray surges are coming from the Crab Nebula

The light from this supernova first reached Earth in July 1054 and was witnessed by astronomers in Japan and China.

When the star exploded, it formed a neutron star, which is the dense core of a star that is about the size of a city like Chicago. This became a pulsar, or rapidly spinning neutron star, that is now located in the nebula.

10.03.2021 - 18:40 [ Independent.co.uk ]

Scientists detect radio blast coming from further away in space than ever before

More distant quasars have been found in the past. But the new one is notable because it is “radio-loud” – it is the first time that radio jets have been able to be detected from such a distant object.

Quasars are among the brightest objects in the universe. They are found at the centre of some galaxies nd are powered by supermassive black holes – when the surrounding gas is eaten by the black hole, it throws out energy that travels across the universe and can be studied by scientists.

04.11.2020 - 18:31 [ MIT Technology Review ]

We just found a source for one of the most mysterious phenomena in astronomy

Spoiler alert: it’s not aliens. Two new studies published in Nature today strongly suggest that magnetars—highly magnetized neutron stars—are one source of FRBs. The studies also indicate that these bursts are probably much more common than we imagined.

08.10.2018 - 22:38 [ Space.com ]

Discovery of a Cosmic-Ray Source Is a Triumph of ‚Multimessenger Astronomy‘

(12.7.2018) As early as the 1780s, French physicist Charles-Augustin de Coulomb noticed that charged particles were neutralizing the electric charge of some of his experiments. In 1912, Austrian scientist Victor Hess first demonstrated that these particles were arriving from space.

08.10.2018 - 21:58 [ Arxiv.org ]

10 Dec 2008: The Antarctic Impulsive Transient Antenna Ultra-high Energy Neutrino Detector Design, Performance, and Sensitivity for 2006-2007 Balloon Flight

This leads to strong motivations to detect the BZ neutrino flux: first, it is required by standard model physics, and thus its absence could signal new physics beyond the standard model.

08.10.2018 - 21:38 [ ScienceMag.org ]

Oddball particles tunneling through Earth could point to new physics

(27.9.2018) However, twice, during its first flight 2006 and its third flight in 2014, ANITA detected odd radio waves with unflipped polarizations coming up from the surface below instead of the horizon. That suggests the signals were produced by upward-zooming air showers triggered by particles that tunneled through Earth. At first blush, that’s not a problem for the standard model. Neutrinos barely interact with matter, so a couple of cosmic neutrinos might have barreled through the planet before smacking an atomic nucleus in the ice and setting off an upward air shower.