Astronomers have spotted a toddler dwarf galaxy 9.4 billion light-years away by turning a cluster of other galaxies into a magnifying glass for X-rays, according to a new paper published in Nature...
What is it: The dwarf galaxy is 10,000 times smaller than the Milky Way itself, yet is brimming with a massive amount of activity. It is currently going through a phase of intense new star formation, resulting in high-energy X-rays pulsing through the region. This is the first time scientists have ever been able to watch this sort of galaxy life stage with X-ray observations.
How did they do it: Galaxy clusters induce gravitational effects on surrounding matter and energy by bending and magnifying it like a glass of water might with a beam of light. This is called gravitational lensing, and scientists can use this phenomenon to study and determine where different electromagnetic signals hailing from other parts of the universe originate from.
Gravitational lensing has never before been used to study X-ray emissions, but the principles of gravitational lensing apply just the same as they would for light. The team used NASA’s Chandra X-ray Observatory to study the Phoenix cluster, 5.7 billion light-years away—a structure that’s a quadrillion times more massive than the sun. It’s a perfect natural lens to magnify X-ray emissions as they pass through.
After subtracting for X-rays coming from the Phoenix cluster itself, the team found “lensed” emissions magnified 60 times over, coming from a dwarf galaxy 9.4 billion-light-years away, born when the universe was a third its current age.
So what?: What exactly happened in the first 5 billion years of the universe is still pretty murky. The authors of the new study say the new detection shows it’s possible to use natural X-ray magnifiers to identify things that were born soon after the Big Bang. Tools like Chandra could now be used to comb over other aspects of the ancient universe and solve cosmological questions in far greater detail.
The news: In the third quarter of this year 40% of the UK’s electricity came from renewables like wind, biomass, and solar, while fossil fuels—virtually all gas in the UK’s case—made up 39%, according...
Why? The milestone is largely due to a few new offshore wind farms that came online from July to September this year. The wind farm industry in the UK is in the midst of a boost as turbines become bigger and more efficient, making projects easier to justify commercially.
But …. It’s worth noting that 12% of electricity in the quarter came from biomass, which may count as renewable, but isn't necessarily carbon free. “In some circumstances [biomass] could lead to higher emissions than from fossil fuels,” Carbon Brief noted, adding that the Committee on Climate Change has urged the UK to shift away from biomass power plants.
The global context: The country has made rapid progress, considering that fossil fuels made up four-fifths of its electricity just a decade ago. However, others are further ahead still, and it’s worth remembering the UK accounts for a tiny proportion of global carbon emissions anyway. Germany passed the same milestone as the UK last year, while Sweden met it seven years ago. The power grids in Iceland, Norway, and Costa Rica run almost entirely on renewable energy already.
However: In the grand scheme of things, three countries matter most: China, the US, and India. Between them, they account for about half of all global carbon emissions. China’s share of renewables in its power-generation mix is almost 27%. In the US it’s just 18%.
Update: This piece was updated to note that biomass produces climate emissions.
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