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The classic film “Alien” was once promoted with the tagline “In space, no one can hear you scream.” Physicists Zhuoran Geng and Ilari Maasilta from the Nanoscience Center at the University of Jyväskylä, Finland, have demonstrated that, on the contrary, in certain situations, sound can be transmitted strongly across a vacuum region.

In a recent article published in Communications Physics they show that in some cases, a sound wave can jump or “tunnel” fully across a vacuum gap between two solids if the materials in question are piezoelectric. In such materials, vibrations (sound waves) produce an electrical response as well, and since an electric field can exist in vacuum, it can transmit the sound waves.

The requirement is that the size of the gap is smaller than the wavelength of the sound wave. This effect works not only in audio range of frequencies (Hz–kHz), but also in ultrasound (MHz) and hypersound (GHz) frequencies, as long as the vacuum gap is made smaller as the frequencies increase.

The iconic movie Alien once claimed: “In space, no one can hear you scream.” However, physicists Zhuoran Geng and Ilari Maasilta from the Nanoscience Center at the University of Jyväskylä, Finland, beg to differ. Their recent research suggests that under specific conditions, sound can indeed be transmitted powerfully across a vacuum.

Their findings, published recently in the journal Communications Physics, reveal that in certain scenarios, sound waves can “tunnel” through a vacuum gap between two solid objects, provided those objects are piezoelectric. These particular materials generate an electrical response when subjected to sound waves or vibrations. Given that an electric field can be present in a vacuum, it can effectively carry these sound waves across.

The requirement is that the size of the gap is smaller than the wavelength of the sound wave. This effect works not only in the audio range of frequencies (Hz-kHz), but also in ultrasound (MHz) and hypersound (GHz) frequencies, as long as the vacuum gap is made smaller as the frequencies increase.

NASA’s Parker Solar Probe marks five successful years in space, achieving milestones like touching the Sun and collecting more than double the expected data. The mission’s continuing journey promises to deepen our understanding of space weather and the Sun’s effects on Earth. Credit: NASA GSFC/CIL/Brian Monroe.

NASA

Established in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is “To discover and expand knowledge for the benefit of humanity.” Its core values are “safety, integrity, teamwork, excellence, and inclusion.” NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals.

The above image may look like a piece of colourful, abstract art, but it is, in fact, a glimpse at the very heart of our galaxy.

Most of us can’t even begin to imagine what lurks beyond our solar system, but astrophysicists in the US have discovered a whole colony of incredible structures at the centre of the Milky Way.

Scientists already knew that mysterious, magnetised strands hang in space, but a new investigation has uncovered a whole new population of them, and found that they are handily pointing in the direction of the galactic centre.

Nobel Prize-winning physicist Eric A. Cornell explains how a record-breaking physics study could help explain the mystery of asymmetry.

These waves can reach heights comparable to stacking three suns on top of each other.

Astronomers have discovered a strange star system with “monster” tidal waves breaking on one of its stars. Astrophysicists from the Center for Astrophysics | Harvard & Smithsonian (CfA) developed new computer models to better understand the impact of huge surface waves.

The new models reveal “titanic waves” created by the tides of a smaller companion star to be repeatedly crashing on the colossal star in the system. This phenomenon has never been detected on a star, making it a significant discovery.

Continue reading “ESA’s Gaia satellite spots ‘retired stars’ passing through young star-forming area” »

Rene Descartes, the father of cartesian philosophy, puts forward the relationship between sciences and especially the relation of metaphysics with other sciences through a metaphor known as the “Tree of Knowledge.” He describes knowledge as a tree and sciences are connected with each other as if they are parts of a tree. Its trunk is physics, its branches are other sciences and the fruit, which is considered to be the goal of a tree, is the science of morals. We are familiar with this metaphor and its varieties in philosophy and Sufism. In particular, it is a common metaphor to accept morals as “the fruit.” Morals, which are the intent of scientific activity, are deemed worthy of being the fruit, or the goal, by many thinkers. As a matter of fact, Ibn Arabi and Qunawi also used the same metaphor. They categorized the science of morals that is often identified with Sufism as the fruit of a tree and the goal of all human endeavors. Descartes completes his metaphor by saying that the tree’s roots are metaphysics. It is the roots that sustain a tree; the trunk, branches and fruits all depend on roots and are nourished by them, which makes the roots the most indispensable part. In this respect, this metaphor can be interpreted as a tribute to metaphysics.

While the tree of knowledge designates the place metaphysics holds among sciences, it seems to correspond with classical metaphysics, at least formally. Because the principal and subsidiary divisions of science (root and branch) are used by classical metaphysics to explain the relation of metaphysics with other sciences, the concepts of “principle and subsidiary” can be replaced by “universal and divisive,” and the meaning will not change: Metaphysics is a universal science and all other sciences serve to it as its particulars. It separates from other sciences, which examine the being from a specific angle, as metaphysics examines being qua being. Its superiority comes from this unique field of research. Because of its superior status, metaphysics is entrusted with another duty: Universal science is the most fundamental field as it certifies the principles of other sciences. The most controversial part of this assertion is whether such a superior science is possible and, if so, what method it has to attain knowledge. We will get to that, but now it is enough to state that: Despite the formal similarities, it is unlikely that Descartes could form a metaphysical understanding through this metaphor in the classical sense.

The classic film “Alien” was once promoted with the tagline “In space, no one can hear you scream.” Physicists Zhuoran Geng and Ilari Maasilta from the Nanoscience Center at the University of Jyväskylä, Finland, have demonstrated that, on the contrary, in certain situations, sound can be transmitted strongly across a vacuum region.

In a recent article published in Communications Physics they show that in some cases, a sound wave can jump or “tunnel” fully across a vacuum gap between two solids if the materials in question are piezoelectric. In such materials, vibrations (sound waves) produce an electrical response as well, and since an electric field can exist in vacuum, it can transmit the sound waves.

The requirement is that the size of the gap is smaller than the wavelength of the sound wave. This effect works not only in audio range of frequencies (Hz–kHz), but also in ultrasound (MHz) and hypersound (GHz) frequencies, as long as the vacuum gap is made smaller as the frequencies increase.

The universe is humming with gravitational radiation—a very low-frequency rumble that rhythmically stretches and compresses spacetime and the matter embedded in it.

That is the conclusion of several groups of researchers from around the world who simultaneously published a slew of journal articles in June describing more than 15 years of observations of millisecond pulsars within our corner of the Milky Way galaxy. At least one group—the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration—has found compelling evidence that the precise rhythms of these pulsars are affected by the stretching and squeezing of spacetime by these long-wavelength gravitational waves.

“This is key evidence for gravitational waves at very low frequencies,” says Vanderbilt University’s Stephen Taylor, who co-led the search and is the current chair of the collaboration. “After years of work, NANOGrav is opening an entirely new window on the gravitational-wave universe.”