A study recently published in the Proceedings of the National Academy of Sciences suggests that harsh environmental conditions were the main source of population decline for the native Polynesians of Easter Island, potentially ending a long-standing debate over the exact cause.
Researchers of the study, led by Dr. Thegn Ladefoged of the University of Auckland in New Zealand, analyzed obsidian artifacts recovered from a number of habitation sites on the island to assess the regional land-use of the local inhabitants, known as the Rapa Nui.
The team found a shift in human uses of different parts of the island, suggesting an attempt to adapt to changing natural environmental conditions. Because of this, the researchers believe that natural barriers and climate extremes may have negatively impacted the islanders enough to lead to population declines. “The results of our research were really quite surprising to me,” said Ladefoged, according to The Huffington Post. “In short, our research does not support the suggestion that societal collapse occurred prior to European contact due to physical erosion and productivity decline, but it does indicate that use of less optimal environmental regions changed prior to European contact.”
The Orionid meteor shower will be visible Monday and Tuesday nights.
There could be as many as 25 meteors per hour at its height, according to EarthSky. If clouds don't interfere with your view, the lack of a bright moon will help in viewing the meteors.
"There's no year better for the Orionids than this one," said astronomer Bob Berman of the astronomy website Slooh. The Orionids get their name because they seem to come from the constellation Orion the Hunter, though the meteors usually can be seen over much of the night sky.
The meteors are actually bits of dust and rocks that are debris from Halley's Comet, caused when Earth comes near the comet's orbit, according to Sky and Telescope magazine.
The actual comet can be seen only every 75 years or so — the next sighting is in 2062 — but this meteor shower is viewable every year around this time. To see the meteors, look to the east and southeast sky between midnight and dawn. Find a place away from lights so your eyes can adapt to the darkness. That can take up to 20 minutes.
Viewing conditions for the Orionid meteor shower.(Photo: AccuWeather)
Tiny clownfish larvae can swim up to 400 kilometres in search of a hospitable anemone – an epic ability that could help them adapt to environmental change, research has found.
The clownfish migrations were discovered by Steve Simpson of the University of Exeter who analysed the DNA of two separate populations.
The groups, from the Arabian Sea, off Oman, live 250 miles (400km) apart.
Mr Simpson and his colleagues captured 136 clownfish from a northern group and 260 from one which lived further south and compared their genetic make-up.
They found one of the clownfish had migrated north from the southern group and 14 had travelled south from the northern group. A small number of the fish in each group were hybrids, suggesting that some of the incomers had bred with natives from the group. Mr Simpson said the fish migrate huge distances in order to share their genes, which helps strengthen their populations.
He suggests the finding could be good news for fish as they face a number of threats from global warming, including the heating up of their habitats and the acidification of seawater.