Supernovas are bad news. They can wreck biospheres and flood planets with deadly radiation. And now, a recent study has added a new potential threat: a special type of supernova that can destroy a planet's ozone layer years after the initial explosion.

When giant stars die in massive explosions called supernovas, they temporarily become some of the most luminous objects in the universe. A single supernova can outshine the combined light of hundreds of billions of stars.

To give you some perspective, the nearby star Betelgeuse is going to explode any day now. (That's an astronomical "any day," meaning sometime within the next few million years.) Even though the star is over 600 light-years from us, when it goes supernova, it will be the brightest object in our sky, second only to the sun. Betelgeuse will be visible during the day, shining brighter than a full moon. For a few weeks, during the peak of the blast, it will be so bright that it will cast shadows in the middle of the night.

Despite the fearsome brightness, the visible light portion of a supernova represents only a tiny fraction of all the energy output. And besides, while intense amounts of visible light may cause blindness, it doesn't have a lot of other serious effects. What's more worrisome is the high-energy radiation associated with the supernova, usually in the form of X-rays and gamma-rays.

A mysterious rise in methane levels in the atmosphere in 2020 may be partly explained by a drop in emissions of nitrogen oxide in the early stages of the covid-19 pandemic.

Methane, a potent greenhouse gas, is responsible for one-fifth of the atmospheric warming linked with human activity. It can be emitted by the production and transport of coal, natural gas and oil, or from biological sources, such as livestock.

Levels of methane in the atmosphere have been rising since 2007, but in 2020 they made their biggest annual jump since records began in 1983.

Vanderbijlpark, South Africa - Breakthrough Listen - the initiative to find signs of intelligent life in the universe - announced today, at a conference organized by the South African Radio Astronomy Observatory (SARAO), the start of observations using a powerful new instrument deployed to the MeerKAT radio telescope in the remote Karoo region of South Africa. The new search for technosignatures - indicators of technology developed by extraterrestrial intelligence - expands the number of targets searched by a factor of 1,000.

The astronomers and engineers on the Breakthrough Listen team have spent the last three years developing and installing the most powerful digital instrumentation ever deployed in the search for technosignatures, and integrating the equipment with the MeerKAT control and monitoring systems in cooperation with SARAO engineers. The new hardware complements Listen's ongoing searches using the Green Bank Telescope in the USA, the Parkes Telescope in Australia, and other telescopes around the world. But while Listen's programs at the GBT and Parkes involve moving these thousand-ton-plus dishes to point at targets all over the sky, the program on MeerKAT usually won't mechanically move the antennas.

"MeerKAT consists of 64 dishes, which can see an area of the sky 50 times bigger than the GBT can view at once," explained Breakthrough Listen Principal Investigator Dr. Andrew Siemion. "Such a large field of view typically contains many stars that are interesting technosignature targets. Our new supercomputer enables us to combine signals from the 64 dishes to get high resolution scans of these targets with excellent sensitivity, all without impacting the research of other astronomers who are using the array."

An international team of astronomers has conducted optical and near-infrared observations of a rare Type Icn supernova known as SN 2022ann. The results of the study, published November 9 on the preprint server arXiv, shed more light on the nature of this supernova and its unique properties.

Supernovae (SNe) are powerful and luminous stellar explosions. They are important for the scientific community as they offer essential clues into the evolution of stars and galaxies. In general, SNe are divided into two groups based on their atomic spectra: Type I and Type II. Type I SNe lack hydrogen in their spectra, while those of Type II showcase spectral lines of hydrogen.

Type Icn SNe are an extreme subtype of interacting stripped-envelope supernovae (SESN). They have strong, narrow oxygen and carbon lines but weak or absent hydrogen and helium lines, presenting additional complications to the stripping mechanism. They have narrow emission features indicative of circumstellar interaction.

To date, only five Type Icn SNe have been discovered, and SN 2022ann is the latest addition to the short list of this SN subtype. SN 2022ann was detected on January 27, 2022 in the faint host galaxy SDSS J101729.72-022535, at a distance of about 710 million light years.

Today's astronomical facilities scan the night sky deeper and faster than ever before. Identifying and classifying known and potentially interesting cosmic events is becoming impossible for one or a group of astronomers. Therefore, increasingly they train computers to do the work for them. Astronomers from the Zwicky Transient Facility collaboration at Caltech have announced that their machine-learning algorithm has now classified and reported 1000 supernovae completely autonomously.

"We needed a helping hand and we knew that once we train our computers to do the job, they would take a big load off our backs", says Christoffer Fremling, a staff astronomer at Caltech and the mastermind behind the new algorithm, dubbed SNIascore. "SNIascore classified its first supernova in April 2021 and a year and a half later we are hitting a nice milestone of 1000 supernovae without any human involvement".

Many of the current and most exciting scientific questions that astronomers are trying to answer require them to collect large samples of different cosmic events. As a result, modern astronomical observatories have become relentless data-generating machines that throw tens of thousands of alerts and images at astronomers every night. This is particularly true in the field of time-domain astronomy, in which researchers look for fast-changing objects, or transients, such as exploding and dying stars known as supernovae, black holes eating orbiting stars, asteroids, and more.

"The traditional notion of an astronomer sitting at the observatory and sieving through telescope images carries a lot of romanticism but is drifting away from reality," says Matthew Graham, the ZTF project scientist at Caltech.

Apart from freeing time for astronomers to pursue other science questions, the machine learning algorithm is much faster at classifying potential supernova candidates and sharing the results with the astronomical community. With SNIascore the process is shortened from 2-3 days to about 10 min, or near real-time. Such early identification of cosmic explosions is often critical to better study their physics.

Team at University of St Andrews says Earth needs to work on communicating with extraterrestrials as first contact could happen any day.
Aliens could get in touch tomorrow and we must know what to say to them, scientists have warned, as they launched a new research hub to prepare humanity for first contact.

The University of St Andrews has joined forces with the UK SETI (Search for Extraterrestrial Intelligence) Research Network to establish protocols and procedures if aliens are found.

The team warn that although there are measures in place for dealing with threats posed by asteroid impacts, there is no agreed response if a radio signal were picked up from another intelligent lifeform.

The Seti Post-Detection Hub will bring together experts from around the world to decide how to decipher methods, enact space law and anticipate societal impacts.

Dr John Elliott, honorary research fellow in the School of Computer Science at St Andrews and coordinator of the Hub, said: "Will we ever get a message from ET? We don't know. We also don't know when this is going to happen.

"But we do know that we cannot afford to be ill prepared - scientifically, socially, and politically rudderless - for an event that could turn into reality as early as tomorrow and which we cannot afford to mismanage.

"We need to coordinate our expert knowledge not only for assessing the evidence but also for considering the human social response, as our understanding progresses and what we know and what we don't know is communicated. And the time to do this is now."

A signature in the X-ray light emitted by a highly magnetised dead star known as a magnetar suggests the star has a solid surface with no atmosphere, according to a new study by an international collaboration co-led by UCL researchers.
The study, published in the journal Science, uses data from a NASA satellite, the Imaging X-ray Polarimetry Explorer (IXPE), which was launched last December. The satellite, a collaboration between NASA and the Italian Space Agency, provides a new way of looking at X-ray light in space by measuring its polarisation - the direction of the light waves' wiggle.

The team looked at IXPE's observation of magnetar 4U 0142+61, located in the Cassiopeia constellation, about 13,000 light years away from Earth. This was the first time polarised X-ray light from a magnetar had been observed.

Magnetars are neutron stars - very dense remnant cores of massive stars that have exploded as supernovae at the ends of their lives. Unlike other neutron stars, they have an immense magnetic field - the most powerful in the universe. They emit bright X-rays and show erratic periods of activity, with the emission of bursts and flares which can release in just one second an amount of energy millions of times greater than our Sun emits in one year. They are believed to be powered by their ultra-powerful magnetic fields, 100 to 1,000 times stronger than standard neutron stars.

The flare was accompanied by a coronal mass ejection that missed Earth.
A surprise solar flare has burst from an area of dense magnetism on the sun's surface, causing a temporary radio blackout in parts of Australia and all of New Zealand.

The M5-class, medium-strength solar flare was recorded by NASA's Solar Dynamics Observatory as it erupted from the sunspot AR3141 at 7:11 p.m. ET on Sunday (Nov. 6). The flare created a rush of radiation that ionized Earth's atmosphere, according to spaceweather.com.

Sunspots are dark regions on the sun's surface where powerful magnetic fields, created by the flow of electrical charges, knot into kinks before suddenly snapping. The resulting release of energy launches bursts of radiation called solar flares and explosive jets of solar material called coronal mass ejections (CMEs). A CME did accompany this flare, but it was not aimed at Earth.

The solar flare erupted unexpectedly and took scientists by surprise. "Our apologies there was no alert for this event. The flare was impulsive," the solar activity tracking website SpaceWeatherLive wrote on Twitter.

The National Oceanic and Atmospheric Administration (NOAA) classifies solar flares in five categories — A, B, C M and X — based on the intensity of the X-rays they release, with each level having 10 times the intensity of the last. TK

Yesterday in Sweden, sky watchers were puzzled when a strange ribbon of blue light appeared during a geomagnetic storm. "It didn't look like any auroras I have ever seen before," says Chad Blakley, the director of Lights over Lapland. One of his tour guides, Miquel Such, video-recorded the phenomenon.

A G1-class geomagnetic storm was underway on Nov. 3rd when the blue ribbon appeared. Webcams saw it first at 1615 UT (5:15 p.m. local Abisko time). It rapidly brightened to naked-eye visibility, then sank below the horizon 30 minutes later. The whole time, regular green auroras danced around and seemingly in front of it: movie [video can be found below]

But what was it?

The asteroid's upper size estimate is just short of the world's tallest building.
A newly discovered, "potentially hazardous" asteroid almost the size of the world's tallest skyscraper is set to tumble past Earth just in time for Halloween, according to NASA.

The asteroid, called 2022 RM4, has an estimated diameter of between 1,083 and 2,428 feet (330 and 740 meters) — just under the height of Dubai's 2,716-foot-tall (828 m) Burj Khalifa, the tallest building in the world. It will zoom past our planet at around 52,500 mph (84,500 km/h), or roughly 68 times the speed of sound.

At its closest approach on Nov. 1, the asteroid will come within about 1.43 million miles (2.3 million kilometers) of Earth, around six times the average distance between Earth and the moon. By cosmic standards, this is a very slender margin.

NASA flags any space object that comes within 120 million miles (193 million km) of Earth as a "near-Earth object" and classifies any large body within 4.65 million miles (7.5 million km) of our planet as "potentially hazardous." Once flagged, these potential threats are closely watched by astronomers, who study them with radar for signs of any deviation from their predicted trajectories that could put them on a devastating collision course with Earth.