2018 provides many things to chew if you are interested in science and the environment. From the strong warning from climate scientists about the dangers of letting temperatures rise above 1.5C to the discovery of a 20 km wide liquid water lake on Mars, it was an impressive year.
Here is a summary of some of the most interesting stories in 2018.
"Safe" limit for heating
The rise in global temperatures of 2C at the end of the century has long been seen as a gateway to dangerous climate change. Researchers argue that keeping within this limit is needed to avoid the most damaging effects of global warming.
But some have pushed the 1.5C target even lower. In October, climate scientists released a large report detailing what would be involved in keeping the temperature rise within the tougher limits.
This will cause millions more people to lose their homes due to rising sea levels, fewer species at risk of extinction and a drastically reduced number of people experiencing water scarcity.
But it will also be very expensive and requires "rapid, wide-ranging and unprecedented change" for the community. The report does not tell the government what to do, but sets out a range of approaches including large reductions in greenhouse gas emissions, a rapid transition to renewable energy and lifestyle and dietary changes.
Another story of climate change from 2018
The earliest animals
More than a million animal species live today are very diverse, from giant ocean blue whales to earthworms writhing under our feet. But their initial evolution from single cell ancestors remained shrouded in mystery.
In the hunt for the earliest animal life, much attention has been focused on a group of enigmatic life forms – known as "Ediacaran biota" – from more than 500 million years ago. These are some of the first complex organisms to appear on Earth.
But their position in the tree of life is difficult to decipher. This strange creature has been categorized as moss, mushrooms, and even as a halfway house between plants and animals.
In September, scientists were able to extract cholesterol molecules from the fossil life forms called Ediacaran Dickinsonia, Which resembles a flat jellyfish. Cholesterol is one of the molecular characteristics of animal life, clearly indicating that Ediacaran biota are animals.
Other paleontological stories from 2018
Giant plastic 'berg
The world plastic waste crisis is one of the major themes in 2018. The problem has been highlighted by the BBC's Blue Planet 2 series, presented by David Attenborough, which contains surprising footage of the destruction that occurred in the oceans and marine life by our addiction to plastic.
In April, our Science Editor, David Shukman, visited Indonesia to report a pile of plastic waste that had clogged rivers and canals in Bandung, on the island of Java, Indonesia. The crisis was very severe, soldiers were called in to help clean large plastic bottles, bags and other plastic packaging.
Worryingly, the problem will only get worse. In March, a report commissioned by the British government stated that the amount of plastic in the ocean could tripled in a decade unless trash was curbed.
The story of other plastic junk from 2018
- Plastic head catcher for ocean cleaning
- Anti-plastic focus & # 39; dangerous interference & # 39;
Destroyer of ghost particles
Neutrinos are some of the fundamental building blocks of the Universe. These subatomic particles glide rapidly around the cosmos, more or less unhindered, interacting with very little. In fact, it is estimated that one particle of neutrinos can pass one light year (about 10 trillion km) of tin without even one atom.
Many of the neutrinos we encounter on Earth originate from the Sun or Earth's atmosphere. But the origin of a group of very high-energy neutrinos remains mysterious until this year. In July, an international team tracked one of them to a remote galaxy that fired "rays" of particles directly to Earth.
This type of galaxy is called blazar. It has a very bright core caused by energy from its large central black hole. When matter falls into the hole, a large emission of charged particles appears, turning this galaxy into a large particle accelerator.
The IceCube experiment in Antarctica has collected data about these very high-energy neutrinos for six years, but this is the first time researchers can match them with sources in the sky.
Other astronomical stories from 2018
Mars watery – and the Moon
We know there is water on Mars in the form of ice, and there are possible signs of occasional fluid flow. But in July, a team of scientists reported the discovery of a 20 km wide lake beneath the planet's south pole ice sheet.
NASA's Curiosity Explorers have explored rock remains from ancient lake beds, but this is the first sign of a persistent body of water today. The results are interesting because scientists have long been looking for signs of today's liquid water on Mars.
"We are not closer to actually detecting life," said Manish Patel, of the British Open University, "but what this finding did was give us a location to see Mars."
Mars is not the only cosmic body that makes watery headlines. In August, researchers published what they said was the surest evidence for ice on the surface of the Moon.
Data from India's Chandrayaan-1 spacecraft shows ice-cold deposits at the north and south poles. This ancient water may be accessible as a resource for future human missions to the Moon.
Other planetary science stories from 2018
What happened to the builders of Stonehenge?
The field of ancient DNA – which involves extracting and analyzing genetic material from people who have long been dead – has given us unprecedented insight into the past. One surprising result from 2018 was the discovery that ancient British people were almost completely replaced in mass migrations from the continent around 4,500 years ago.
Neolithic Britons had just set up large stones at Stonehenge when they were controlled by newcomers known as the Beaker people. This resulted in 90% of the British gene collection being replaced in just a few hundred years. Why this happened is unknown. But disease, hunger and conflict are all potential candidates.
In a different study released in 2018, researchers showed that a 50,000-year-old bone fragment from Russia belonged to a girl who was half Denisovan and half Neanderthal. Denisovans and Neanderthals are different human species that inhabit Eurasia before our species – Homo sapiens – leave Africa.
Another ancient DNA story from 2018
- Early Englishmen had dark skin and blue eyes
- DNA describes settlements in the Pacific
In November, scientists identified what appeared to be a large impact crater under Greenland ice. The 31 km wide depression emerged when scientists examined radar images of the island's bedrock.
The bowl might have been dug up by iron asteroids as wide as 1.5 km around 12,000 to three million years ago. Some researchers doubt the evidence presented so far. But he has raised some interesting possibilities, including the possibility of connection to a strong cooling period that marks the warming of the climate seen when the Earth emerged from the height of the last Ice Age.
There is a long-standing hypothesis that this drop in temperature could be due to sunlight being blocked by debris thrown into the atmosphere by the impact and smoke and ash from the wildfires that trigger it. If further work confirms the age of the crater close to the lower end of the age range, that could trigger interest in this long debate.
Other earth science stories from 2018:
- East Antarctic glaciers are in turmoil
- How Greenland burned its bottom
A variety of evidence shows that the ancestors of most humans living outside Africa left the continent in one migration 60,000 years ago. But there is some evidence that pioneered modern humans (Homo sapiens) committed robbery outside Africa before this time.
In January, scientists revealed the jawbone of a modern human who died in Israel 185,000 years ago, tens of thousands of years earlier than before. Accepted wisdom shows that these previous visits failed to provide a permanent footing for modern humans in Eurasia.
But this jawbone fits the picture that emerged of previous African outflows that spread further to Eurasia than many believed. These pioneers seemed to live side by side with other human species such as Neanderthals and Denisovas. But it remains a mystery why their genetic signature is not preserved in people living today.
Another story of human evolution from 2018
Rock from Mars
After years of discussion and mis-start, European and American space agents made their first significant move to bring back rocks from Mars.
In April, NASA and Esa signed a letter of intention that would lead to the first "round trip" to another planet.
The effort will enable scientists to begin answering key questions about the history of Mars, including whether the planet once hosted life. But that would also allow geologists to begin to build accurate chronologies for events in the history of Mars.
The US mission over the past few decades has contributed greatly to our understanding of the Red Planet there, but there are mass constraints on experiments that can be accommodated on loads intended for Mars.
There is no comparison with information that scientists can obtain from studying rocks and Mars soil with scientific instruments available in terrestrial laboratories.
Another space exploration story from 2018
Plastic in our water
Plastic waste is increasingly pervasive in our daily lives, and this extends to our drinking water. Research by Orb Media journalism organization found an average of 10 plastic particles per liter in the main brand of bottled water.
In the largest investigation of its kind, 250 bottles purchased in nine different countries were examined. Almost all of them contain small plastic particles.
Our northernmost planet is often regarded as a pristine wilderness. But this year, the researchers voiced their concerns about the large concentration of plastic that accumulates in Arctic sea ice.
The number of particles in only one liter of melting Arctic sea ice is found to be higher than in the open ocean. Scientists say there is a need for further research on its effects on zooplankton, invertebrates, fish, seabirds, and mammals.
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