Astronomy

Here’s what a chef, a vet and two anthropologists have to say about eating periodical cicadas

Someday an unlucky outburst from our sun could strike Earth and fry most of our electronics—and we’ve already had some too-close-for-comfort near misses

It’s difficult to actually visualise a universe that is changing. Things tend to happen at snails pace albeit with the odd exception. Take the formation of galaxies growing in the early universe. Their immense gravitational field would suck in dust and gas from the local vicinity creating vast collections of stars. In the very centre of these young galaxies, supermassive blackholes would reside turning the galaxy into powerful quasars. A recent survey by the James Webb Space Telescope (JWST) reveals that black holes can create a powerful solar wind that can remove gas from galaxies faster than they can form into stars, shutting off the creation of new stars.

To remove the confusion and mystique around black holes, they are the corpse of massive stars. When supermassive stars collapse at the end of their lives their core turns into a point source that is so incredibly dense that even light, travelling at 300,000 kilometres per second, is unable to escape. It’s believed that many galaxies have supermassive black holes at their core. 

Swift scene change to the earlier part of the life of a star. Fusion in the core generates incredible amounts of energy as new elements are synthesised. Along with new elements, heat and light, a powerful outflow of electrically charged particles rushes away and permeates the surrounding space. Here in our Solar System, charged particles rush Earthward and on arrival we experience the glorious display of the northern lights. 

Visualization of the solar wind encountering Earth’s magnetic “defenses” known as the magnetosphere. Clouds of southward-pointing plasma are able to peel back layers of the Sun-facing bubble and stack them into layers on the planet’s nightside (center, right). The layers can be squeezed tightly enough to reconnect and deliver solar electrons (yellow sparkles) directly into the upper atmosphere to create the aurora. Credit: JPL

A team of astronomers using the JWST have found that, over 90 percent of the wind that flows through a distant galaxy is made of neutral gas and to date, has been invisible. Until recently it was only possible to detect ionised gas – gas which carries an electric charge – which is warm. The neutral gas in the study revealed that neutral gas was cold but JWST was able to detect it. 

The powerful outflow of neutral gas is thought to come from the supermassive blackholes at the core of some galaxies at the edge of the Universe. The team, led by Dr Rebecca Davies from Swinburne University first identified that black hole driven outflow in a distant galaxy over 10 billion light years away. The paper published in Nature explains how ‘The outflow is removing gas faster than gas is being converted into stars, indicating that the outflow is likely to have a very significant impact on the evolution of the galaxy.’

With a lack of gas and dust, star formation will slow and eventually stop. Just like a forest that always has new trees growing to replace old, dying trees, so galaxies usually have star formation to replace dying stars. Ultimately the forest, and a galaxy will be unable to grow and develop and eventually become static and slowly die with the final stars blinking out. 

This is a JWST view of the Crab Nebula. Like other supernovae, a star exploded to create this scene.The result is a rapidly spinning neutron star (a pulsar) at its heart, surrounded by material rushing out from the site of the explosion. SN 2022jli could have either a neutron star or a black hole orbiting with a companion star.

The team found that the active galactic nuclei with supermassive black holes are the driving force behind this outflow of gas. Those with the most massive black holes can even strip the host galaxy of all the star forming gasses playing a major role in the evolution of the galaxy. 

Source : New JWST observations reveal black holes rapidly shut off star formation in massive galaxies

The post Black Holes Can Halt Star Formation in Massive Galaxies appeared first on Universe Today.

Satellite images capture striking differences between the 2017 and 2024 total solar eclipses that swept across North America, including variations in the moon's shadow along the path of totality.

Ahead of a project to spray carbon dioxide into jungle plots, researchers contemplate what its results might signal about the forest’s future.

All the planets now huddle around our line of sight toward the Sun. However, these moonless evenings present us the Spring Triangle, the Great Diamond with a sugar sprinkle on its edge, and the Pointers aligned vertically.

The post This Week's Sky at a Glance, April 26 – May 5 appeared first on Sky & Telescope.

Political campaigns are deploying AI-generated deepfake versions of politicians to reach hundreds of millions of eligible voters in India’s 2024 election – the world’s largest ever

Political campaigns are deploying AI-generated deepfake versions of politicians to reach hundreds of millions of eligible voters in India’s 2024 election – the world’s largest ever

Image: The Copernicus Sentinel-2 mission takes us over part of the Seychelles, an island republic in the western Indian Ocean.

The medicines nalmefene and naltrexone helped compulsive gamblers reduce their betting activities, trials have shown

The medicines nalmefene and naltrexone helped compulsive gamblers reduce their betting activities, trials have shown

We are all very familiar with the concept of the Earth’s magnetic field. It turns out that most objects in space have magnetic fields but it’s quite tricky to measure them. Astronomers have developed an ingenious way to measure the magnetic field of the Milky Way using polarised light from interstellar dust grains that align themselves to the magnetic field lines. A new survey has begun this mapping process and has mapped an area that covers the equivalent of 15 times the full Moon. 

Many people will remember experiments in school with iron filings and bar magnets to unveil their magnetic field. It’s not quite so easy to capture the magnetic field of the Milky Way though. The new method to measure the field relies upon the small dust grains which permeate space between the stars. The grains of dust are similar in size to smoke particles but they are not spherical. Just like a boat turning itself into the current, the dust particles’ long axis tends to align with the local magnetic field. As they do, they emit a glow in the same frequency as the cosmic background radiation and it is this that astronomers have been tuning in to. 

Infrared image of the shockwave created by the massive giant star Zeta Ophiuchi in an interstellar dust cloud. Credit: NASA/JPL-Caltech; NASA and The Hubble Heritage Team (STScI/AURA); C. R. O’Dell, Vanderbilt University

Not only do the particles glow but they also absorb starlight that passes through them just like polarising filters. The polarisation of light is familiar to photographers that might use polarising filters to darken skies and manage reflections. The phenomenon of polarisation refers to the propagation of light. As it moves through a medium it carries energy from one place to another but on the way it displays wave like characteristics. The wave nature is made up of alternating displacements of the medium through which they are travelling (imagine a wave in water). The displacement is not always the same as the direction of travel; sometimes it is parallel and at other times it is perpendicular. In polarisation, the displacement is limited to one direction only. 

In the particles in interstellar space, the polarising properties capture the magnetic field and polarise the light that travels through them revealing the details of the magnetic field. Just as they are on Earth, magnetic field lines are of crucial importance to galactic evolution. They regulate star formation, shape the structure of a galaxy and like gigantic galactic rivers, shape and direct the flow fo gas around the galaxy. 

Researchers from the Inter-University Institute for High Energies in Belgium used the PASIPHAE survey – an international collaboration to explore the magnetic field from the polarisation in interstellar dust – to start the process. They measured the polarisation of more than 1500 stars which covered an area of the sky no more than 15 times the size of the full Moon. The team then used data from the Gaia astrometry satellite and a new algorithm to map the magnetic fields in the galaxy in that part of the sky. 

This is the first time that any large scale project has attempted to map the gravitational field of the Milky Way. It will take some time to complete the full mapping but it when complete it will provide great insight not just into the magnetic field of galaxies but to the evolution of galaxies across the universe. 

Source : A first glimpse at our Galaxy’s magnetic field in 3D

The post Mapping the Milky Way’s Magnetic Field in 3D appeared first on Universe Today.

In just 2 hours, small metal robots can capture most nanoscopic plastic particles from a sample of water

In just 2 hours, small metal robots can capture most nanoscopic plastic particles from a sample of water

Boeing's Starliner capsule has been cleared for its first-ever crewed launch, a test flight scheduled to send two astronauts toward the International Space Station on May 6.

In the 1970s a young psychologist challenged a popular theory of how we acquire language, launching a fierce debate that continues to this day

Solar Sails are an enigmatic and majestic way to travel across the gulf of space. Drawing an analogy to the sail ships of the past, they are one of the most efficient ways of propelling craft in space. On Tuesday a RocketLab Electron rocket launched NASA’s new Advanced Composite Solar Sail System. It aims to test the deployment of large solar sails in low-earth orbit and on Wednesday, NASA confirmed they had successfully deployed a 9 metre sail. 

In 1886 the motor car was invented. In 1903 humans made their first powered flight. Just 58 years later, humans made their first trip into space on board a rocket. Rocket technology has changed significantly over the centuries, yes centuries. The development of the rocket started way back in the 13th Century with the Chinese and Mongolians firing rocket propelled arrows at each other. Things moved on somewhat since then and we now have solid and liquid rocket propellant, ion engines and solar sails with more technology in the wings. 

A SpaceX Falcon 9 rocket rises from its Florida launch pad to send Intuitive Machines’ Odysseus moon lander spaceward. (NASA via YouTube)

Solar sails are of particular interest because they harness the power of sun, or star light to propel probes across space. The idea isn’t knew though, Johannes Kepler (of planetary motion fame) first suggested that sunlight could be used to push spacecraft in the 17th Century in his works entitled ‘Somnium’. We had to wait until the 20h Century though before Russian scientist Konstantin Tsiolkovsky outlined the principle of how solar sails might actually work. Carl Sagan and other members of the Planetary Society start to propose missions using solar sails in the 70’s and 80’s but it wasn’t until 2010 that we saw the first practical solar sail vehicle, IKAROS.

Image of the fully deployed IKAROS solar sail, taken by a separation camera. Credit: JAXA

The concept of solar sails is quite simple to understand, relying upon the pressure of sunlight. The sails are angled such that photons strike the reflective sail and bounce off it to push the spacecraft forward. It does of course take a lot of photons to accelerate a spacecraft using light but slowly, over time it is a very efficient propulsion system requiring no heavy engines or fuel tanks. This reduction of mass makes it easier for solar sails to be accelerated by sunlight but the sail sizes have been limited by the material and structure of the booms that support them. 

NASA have been working on the problem with their Next Generation Solar Sail Boom Technology. Their Advanced Composite Solar Sail System uses a CubeSat built by NanoAvionics to test a new composite boom support structure. It is made from flexible polymer and carbon fibre materials to create a stiffer, lighter alternative to existing support structure designs. 

On Wednesday 24 April, NASA confirmed that the CubeSat has reached low-Earth orbit and deployed a 9 metre sail. They are now powering up the probe and establishing ground contract. It took about 25 minutes to deploy the sail which spans 80 square metres. If the conditions are right, it may even be visible from Earth, possibly even rivalling Sirius in brightness. 

Source : Solar Sail CubeSat Has Deployed from Rocket

The post NASA’s New Solar Sail Has Launched and Deployed appeared first on Universe Today.

The neurons in wasp brains that help them recognise hive mates are similar to those in the brains of primates, including humans

The neurons in wasp brains that help them recognise hive mates are similar to those in the brains of primates, including humans

Two Russian cosmonauts completed a spacewalk at the International Space Station on April 25, wrapping up all of their tasks with time to spare, including the deployment of a radar that they began last year.