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Strange sounds recorded high in Earth's atmosphere have scientists baffled
May 11, 2023
Scientists have detected sounds high in Earth's atmosphere that can't be identified.
A solar-powered balloon mission launched by researchers from Sandia National Laboratories carried a microphone to a region of Earth's atmosphere found around 31 miles (50 km) above the planet called the stratosphere. This region is relatively calm and free of storms, turbulence and commercial air traffic, meaning microphones in this layer of the atmosphere can eavesdrop on the sounds of our planet, both natural and human-made.
However, the microphone in this particular study also heard strange sounds that repeat a few times per hour. Their source has yet to be identified. The sounds were recorded in the infrasound range, meaning they were at frequencies of 20 hertz (Hz) and lower, well below the range of the human ear. "There are mysterious infrasound signals that occur a few times per hour on some flights, but the source of these is completely unknown," Daniel Bowman of Sandia National Laboratories said in a statement.
To gather acoustic data from the stratosphere, Bowman and the team used devices initially designed to monitor volcanoes called microbarometers that are capable of detecting detect low-frequency sounds.
Along with the expected natural and man-made sounds, the microbarometers detected the mysterious repeating infrasound signals.
The sensors were carried aloft by balloons that Bowman and fellow researchers built. Featuring diameters between 20 and 23 feet (6 and 7 meters), the balloons were built from common and inexpensive materials. Powered by sunlight, these deceptively simple devices were able to climb to altitudes of around 70,000 feet (13.3 miles) over Earth.
"Our balloons are basically giant plastic bags with some charcoal dust on the inside to make them dark," Bowman said. "We build them using painter's plastic from the hardware store, shipping tape, and charcoal powder from pyrotechnic supply stores. When the sun shines on the dark balloons, the air inside heats up and becomes buoyant."
Bowman explained that this passive solar power is enough to propel the balloons from the surface of the planet to the stratosphere. After launch, the balloons were tracked using GPS, something that the team had to do because balloons can often fly for hundreds of miles and may land in difficult-to-navigate regions of the planet.
And, as recent events have shown, scientific balloons can be mistaken for other objects, sometimes causing unintentional alarm.
In addition to helping further investigate these mysterious stratospheric sounds, solar-powered balloons like these could be used to investigate mysteries much further from Earth.
Such vehicles are currently being tested to discover if they could be partnered with a Venus orbiter to observe seismic and volcanic activity through its thick atmosphere. Robotic balloons could drift through the upper atmosphere of "Earth's evil twin," high above its hellishly hot and high-pressure surface investigating its thick atmosphere and clouds of sulfuric acid.
https://www.space.com/strange-sounds-stratosphere-balloon-infrasound
https://www.eurekalert.org/news-releases/988280?
A powerful eruption on the sun could create widespread auroras tonight
May 11, 2023
Late Tuesday, the satellite known as the Solar and Heliospheric Observatory, or SOHO, detected a significant coronal mass ejection (CME) which likely was spawned by the double flare outburst that afternoon. The associated subatomic material appears to be headed directly toward Earth and, as a result, the Space Weather Prediction Center at the National Oceanographic and Atmospheric Administration (NOAA) has issued a geomagnetic storm watch(opens in new tab) for a possible G3 event today (May 11).
Such a geomagnetic storm might allow auroras to be visible as far south as the border of Oregon and northern California, Denver, Colorado and the Outer Banks of North Carolina.
For much of this past week, the sun has been behaving in a highly disturbing manner. Since May 5, a sunspot cataloged as AR3296 has been slowly working its way across the disk of the sun and in the process has hurled no fewer than nine magnetically charged "M" class solar flares toward Earth. These flares have caused frequent disruptions or even blackouts in shortwave radio communications throughout the world. Compass needles have danced back and forth, while utility companies have braced for stray surges of current that could even knock out their power lines.
But on Tuesday (May 9), within a time span of less than two hours, two significant solar flares erupted from sunspot AR3296. Great streams of subatomic particles shot out from these solar disturbances at terrific speeds of 2.2 million mph (1.3 million km/h). When these particles encounter Earth's magnetic field, some of them may be accelerated and channeled down to areas around the North and South Poles.
https://www.space.com/sun-auroras-strong-geomagnetic-storm-watch-may-2023
https://www.swpc.noaa.gov/news/g3-strong-geomagnetic-storm-watch-now-effect-11-may
ESO telescope reveals hidden views of vast stellar nurseries
May 11, 2023
“In these images we can detect even the faintest sources of light, like stars far less massive than the Sun, revealing objects that no one has ever seen before,” says Stefan Meingast, an astronomer at the University of Vienna in Austria and lead author of the new study published today in Astronomy & Astrophysics. “This will allow us to understand the processes that transform gas and dust into stars.”
Stars form when clouds of gas and dust collapse under their own gravity, but the details of how this happens are not fully understood. How many stars are born out of a cloud? How massive are they? How many stars will also have planets?
To answer these questions, Meingast’s team surveyed five nearby star-forming regions with the VISTA telescope at ESO’s Paranal Observatory in Chile. Using VISTA’s infrared camera VIRCAM, the team captured light coming from deep inside the clouds of dust. “The dust obscures these young stars from our view, making them virtually invisible to our eyes. Only at infrared wavelengths can we look deep into these clouds, studying the stars in the making,” explains Alena Rottensteiner, a PhD student also at the University of Vienna and co-author of the study.
The survey, called VISIONS, observed star-forming regions in the constellations of Orion, Ophiuchus, Chamaeleon, Corona Australis and Lupus. These regions are less than 1500 light-years away and so large that they span a huge area in the sky. The diameter of VIRCAM’s field of view is as wide as three full Moons, which makes it uniquely suited to map these immensely big regions.
The team obtained more than one million images over a period of five years. The individual images were then pieced together into the large mosaics released here, revealing vast cosmic landscapes. These detailed panoramas feature dark patches of dust, glowing clouds, newly-born stars and the distant background stars of the Milky Way.
Since the same areas were observed repeatedly, the VISIONS data will also allow astronomers to study how young stars move. “With VISIONS we monitor these baby stars over several years, allowing us to measure their motion and learn how they leave their parent clouds,” explains João Alves, an astronomer at the University of Vienna and Principal Investigator of VISIONS. This is not an easy feat, as the apparent shift of these stars as seen from Earth is as small as the width of a human hair seen from 10 kilometres away. These measurements of stellar motions complement those obtained by the European Space Agency’s Gaia mission at visible wavelengths, where young stars are hidden by thick veils of dust.
https://www.eso.org/public/news/eso2307/?lang
https://visions.univie.ac.at/