Twitter egg hatches into neutral human silhouette

Leiden, Jul 2: Astronomers have discovered a luminous galaxy caught in the act of reionizing its surrounding gas only 800 million years after the Big Bang.

The research, led by Romain Meyer, PhD student at UCL in London, UK, has been presented at the virtual annual meeting of the European Astronomical Society (EAS).

Studying the first galaxies that formed 13 billion years ago is essential to understanding our cosmic origins. One of the current hot topics in extragalactic astronomy is 'cosmic reionization,' the process in which the intergalactic gas was ionized (atoms stripped of their electrons).

Cosmic reionization is similar to an unsolved murder: We have clear evidence for it, but who did it, how and when? We now have strong evidence that hydrogen reionization was completed about 13 billion years ago, in the first billion years of the universe, with bubbles of ionized gas slowly growing and overlapping.

The objects capable of creating such ionized hydrogen bubbles have however remained mysterious until now: the discovery of a luminous galaxy in which 60-100 percent of ionizing photons escape, is likely responsible for ionizing its local bubble. This suggests the case is closer to being solved.

The two main suspects for cosmic reionization are usually 1) a population of numerous faint galaxies leaking ~10 percent of their energetic photons, and 2) an 'oligarchy' of luminous galaxies with a much larger percentage (>50 percent) of photons escaping each galaxy.

In either case, these first galaxies were very different from those today: galaxies in the local universe are very inefficient leakers, with only <2-3 percent of ionizing photons escaping their host. To understand which galaxies governed cosmic reionization, astronomers must measure the so-called escape fractions of galaxies in the reionization era.

The detection of light from excited hydrogen atoms (the so-called Lyman-alpha line) can be used to infer the fraction of escaping photons. On the one hand, such detections are rare because reionization-era galaxies are surrounded by neutral gas which absorbs that signature hydrogen emission.

On the other hand, if this hydrogen signal is detected it represents a 'smoking gun' for a large ionized bubble, meaning we have caught a galaxy reionizing its surroundings. The size of the bubble and the galaxy's luminosity determines whether it is solely responsible for creating this ionized bubble or if unseen accomplices are necessary.

The discovery of a luminous galaxy 800 million years after the Big Bang supports the scenario where an 'oligarchy' of bright leakers emits most of the ionizing photons.

"It is the first time we can point to an object responsible for creating an ionized bubble, without the need for a contribution from unseen galaxies.

Additional observations with the upcoming James Webb Space Telescope will enable us to study further what is likely one of the best suspects for the unsolved case of cosmic reionization," said Meyer.

Melbourne, Jul 24: Home-made cloth face masks may need a minimum of two layers, and preferably three, to prevent the dispersal of viral droplets associated with Covid-19, according to a study.

Researchers, including those from the University of New South Wales in Australia, noted that viral droplets are generated by those infected with the novel coronavirus when they cough, sneeze, or speak.

As face masks have been proven to protect healthy people from inhaling infectious droplets as well as reducing the spread from those who are already infected, several types of material have been suggested for these, but based on little or no evidence of how well they work, the scientists said.

In the current study, published in the journal Thorax, the researchers compared the effectiveness of single and double-layer cloth face coverings with a surgical face mask (Bao Thach) at reducing droplet spread.

They said the single layer covering was made from a folded piece of cotton T shirt and hair ties, and the double layer covering was made using the sew method described by the US Centers for Disease Control and Prevention (CDC).

The scientists used a tailored LED lighting system and a high-speed camera to film the dispersal of airborne droplets produced by a healthy person with no respiratory infection, during speaking, coughing, and sneezing while wearing each type of mask.

Their analysis showed that the surgical face mask was the most effective at reducing airborne droplet dispersal, although even a single layer cloth face covering reduced the droplet spread from speaking.

But the study noted that a double layer covering was better than a single layer in reducing the droplet spread from coughing and sneezing.

According to the researchers, the effectiveness of cloth face masks is dependent on the number of layers of the covering, the type of material used, design, fit as well as the frequency of washing.

Based on their observations, they said a home made cloth mask with at least two layers is preferable to a single layer mask.

"Guidelines on home-made cloth masks should stipulate multiple layers," the scientists said, adding that there is a need for more research to inform safer cloth mask design.

San Francisco, Feb 5: After a German artist, Simon Weckert, demonstrated how he "hacked" Google Maps with 99 smartphones and a wagon to create "virtual traffic jams" on the streets of Berlin, Google responded to the incident saying it "appreciates" creative use of maps.

Admitting that it has not quite cracked travelling by wagon, the tech giant also hinted that it might use cases like this to improve how its maps work.

"We appreciate seeing creative uses of Google Maps like this as it helps us make maps work better over time," 9to5Google quoted a Google spokesperson as saying.

In a YouTube video, Weckert showed that he put 99 smartphones with Google Maps onto a small wagon cart and then wheeled that cart around various streets in Berlin, including outside the Google office, Android Authority reported on Monday.

The smartphones "apparently fooled Google Maps" into thinking that there was a high concentration of users on those streets.

Because the second-hand phones were in a cart, Maps was further tricked into believing that the traffic was slow-moving.

As a result, the navigation app started showing virtual traffic jams by turning green streets to red in the online navigational tool, showcasing how digital technology can have a real impact on the real world.

"Traffic data in Google Maps is refreshed continuously thanks to information from a variety of sources, including aggregated anonymised data from people who have location services turned on and contributions from the Google Maps community," the Google spokesperson said.

"We've launched the ability to distinguish between cars and motorcycles in several countries including India, Indonesia and Egypt, though we haven't quite cracked travelling by wagon," the statement added. After a German artist, Simon Weckert, demonstrated how he "hacked" Google Maps with 99 smartphones and a wagon to create "virtual traffic jams" on the streets of Berlin, Google responded to the incident saying it "appreciates" creative use of maps.

Admitting that it has not quite cracked travelling by wagon, the tech giant also hinted that it might use cases like this to improve how its maps work.

"We appreciate seeing creative uses of Google Maps like this as it helps us make maps work better over time," 9to5Google quoted a Google spokesperson as saying.

In a YouTube video, Weckert showed that he put 99 smartphones with Google Maps onto a small wagon cart and then wheeled that cart around various streets in Berlin, including outside the Google office, Android Authority reported on Monday.

The smartphones "apparently fooled Google Maps" into thinking that there was a high concentration of users on those streets.

Because the second-hand phones were in a cart, Maps was further tricked into believing that the traffic was slow-moving.

As a result, the navigation app started showing virtual traffic jams by turning green streets to red in the online navigational tool, showcasing how digital technology can have a real impact on the real world.

"Traffic data in Google Maps is refreshed continuously thanks to information from a variety of sources, including aggregated anonymised data from people who have location services turned on and contributions from the Google Maps community," the Google spokesperson said.

"We've launched the ability to distinguish between cars and motorcycles in several countries including India, Indonesia and Egypt, though we haven't quite cracked travelling by wagon," the statement added.