Near-Earth asteroid could be a piece of the Moon
An asteroid called Kamo`oalewa likely has lunar origins, according to US astronomers, who analysed its composition and found that it matches lunar rocks from NASA’s Apollo missions.
About the size of a fairground Ferris wheel, Kamo`oalewa is classified as a “quasi-satellite” – a subcategory of asteroids that orbit the Sun but stick close to Earth. Only five quasi-satellites are known, and this one’s orbital path is another clue to its origins.
“It is very unlikely that a garden-variety near-Earth asteroid would spontaneously move into a quasi-satellite orbit like Kamo`oalewa’s,” says study co-author Renu Malhotra, from the University of Arizona. “It will not remain in this particular orbit for very long, only about 300 years in the future, and we estimate that it arrived in this orbit about 500 years ago.”
Malhotra and colleagues speculate that Kamo`oalewa may have originated as debris from the original impact that created the Moon.
The research is published in Nature Communications.
Your cat can track your ‘invisible presence’
Ever felt watched by your cat? A Japanese-led team of researchers has found that pet cats keep mental tabs on their owners. When stationary, they can track their owner’s movements through the house using audio cues (mostly the owner’s voice), and are surprised if a voice comes from a different location than expected.
“Mental representations about the whereabouts of living things such as other group members, predators, or prey are likely to be advantageous for many animals, especially in conditions of poor visibility,” the authors explain in their paper, published in PLOS ONE.
With sensitive ears that can move independently in all directions, cats are well-placed to be good at creating mental maps from sound. This study confirmed that they are, by putting cats in a familiar room and then playing sounds (of their owner, a familiar cat, and a non-social sound) from speakers.
The researchers then played the voices from speakers further away, which surprised the cats.
“Results showed that cats were surprised when their owner appeared to be “teleported” to a new, unexpected location, but they did not react in the same way when tested with non-social stimuli,” the researchers write. “These results suggest that cats hold a mental representation of the unseen owner and map their owner’s location from the owner’s voice, showing evidence of socio-spatial cognition.”
Did volcanoes trigger the collapse of Chinese dynasties?
Volcanoes could have caused the fall of several Chinese dynasties over the last 2000 years, according to research led by Zhejiang University in China.
By using ice cores to date eruptions and comparing this with historical records, the team found that 62 out of the 68 dynasty collapses were preceded by at least one volcanic eruption.
So what could be the link?
Abrupt climate changes, the researchers say.
“Volcanic eruptions are one of the most important drivers of sudden and pronounced short-term climatic variability,” they explain in their paper in Nature Communications – largely because volcanic aerosols in the atmosphere can scatter sunlight and cool down local climate, as well as reducing evaporation over water bodies.
“Major eruptions can thus introduce a double jeopardy of marked coldness and drought during the agricultural growing season.”
This would profoundly impact societies, but the eruption-dynasty collapse link is complex; for example, eruptions seemed to particularly impact unstable or already vulnerable regions, such as those with ongoing warfare.
“Volcanically induced climatic shock should now take a prominent place among (and be integrated with) the constellation of factors frequently assigned a role in these events,” the researchers conclude.
Your music preferences have daily rhythms
While you wait to see your 2021 Spotify Wrapped, researchers are already using listening data from the streaming service to study your music habits.
A paper in Royal Society Open Science has studied over two billion streaming events (comprising 3.7 million unique tracks) to find that over the course of a single day, there are five distinct phases of music preference: morning, afternoon, evening, night, and late night/early morning.
Each is defined by different fluctuations in music type, defined by things like tempo, loudness and danceability. For example, people like louder music in the morning, but quieter music in the evening. Tempo and danceability are low in the early afternoon but peak at night.
“Our results demonstrate how music intertwines with our daily lives and highlight how even something as individual as musical preference is influenced by underlying diurnal patterns,” the scientists conclude – though they note that their results are biased towards Western culture.
Climate change is transforming birds’ bodies
Even the most pristine parts of the Amazon Rainforest are being affected by human-induced climate change, say scientists who have discovered that birds’ bodies are changing in response to hot and dry conditions.
“Even in the middle of this pristine Amazon rainforest, we are seeing the global effects of climate change caused by people, including us,” said Vitek Jirinec, Integral Ecology Research Center in California and lead author of the study, published Science Advances.
The study collected data on more than 15,000 individual birds from 77 species, over 40 years of fieldwork across a large span of the Amazon Rainforest. It found that the birds have become smaller and their wings have lengthened over several generations.
Jirinec and team say this indicates a response to changing environmental conditions that bring physiological and nutritional challenges.
“This is undoubtedly happening all over and probably not just with birds,” says co-author Philip Stouffer from Louisiana State University. “If you look out your window, and consider what you’re seeing out there, the conditions are not what they were 40 years ago and it’s very likely plants and animals are responding to those changes as well.
“We have this idea that the things we see are fixed in time, but if these birds aren’t fixed in time, that may not be true.”