Last images from DART as it crashed into an asteroid

NASA smashed a spacecraft into an asteroid on purpose on Monday, and we all got a ringside seat. The Double Asteroid Redirection Test (DART) probe rammed into the harmless asteroid Dimorphos to test whether humanity could reroute a dangerous asteroid heading for Earth. DART took pictures every second as it approached the space rock. Telescopes on Earth watched the collision. And a tiny satellite flew alongside and photographed the impact, which took place 11 million kilometres from Earth. Studying its shots of the plume of debris that was ejected from Dimorphos will help scientists to understand exactly how the impact unfolded.

China’s Mars rover finds hints of catastrophic floods

China’s Zhurong rover has peered under the surface of Mars — down to 100 metres — and has found evidence of two huge floods that shaped the landscape. Since May last year, Zhurong has been exploring Utopia Planitia, in Mars’s northern hemisphere. Images from the rover’s ground-penetrating radar found layered patterns under the surface, which the authors suggest are made of sedimentary rocks carried in by two major floods around 3 billion and 1.6 billion years ago. But other scientists say that, although radar is good at detecting layers of subsurface material, it’s less proficient at identifying what layers are made of.

NASA’s Mars rover makes ‘fantastic’ find in search for past life

Since July, NASA’s Perseverance rover has drilled and collected four slim cores of sedimentary rock, formed in what was once a river delta on Mars. They are the first of this type of rock to be gathered on another world — and scientists are excited because at least two of the cores probably contain organic compounds, which, on Earth, are often associated with living things. If all goes well, the samples will be the first ever returned from Mars. They will be picked up by another spacecraft and brought back to Earth no earlier than 2033.

‘Lunar wobble’ influences mangrove growth

Long-term fluctuations in the Moon’s orbit — known as the lunar wobble — could influence mangrove canopy growth. Researchers in Australia used high-resolution satellite images to measure mangrove canopy across the continent between 1987 and 2020. They found that the wobble, which pulls low tides lower and high tides higher in a cyclic pattern that lasts about 18 years, was a major factor in the expansion and contraction of mangrove growth. Depending on the phase of wobble, mangrove ecosystems get less water — resulting in thinner canopy cover — or higher tides that increase growth. Mangroves are natural carbon sinks, so the findings could help to better assess how much carbon they will store over time.

Genes May Explain HowThis Jellyfish Can Live Forever

The tiny translucent jellyfish Turritopsis dohrnii can revert to an immature polyp state and revive itself again and again — effectively making it immortal. Researchers have now sequenced the jellyfish’s genome and studied the genes involved in its rejuvenation. They found that genes associated with DNA storage were highly expressed in adult jellyfish, but reduced as the animals transformed into polyps. However, genes linked to pluripotency, or the ability of cells to turn into any cell type, were increasingly expressed as the jellyfish reverted.

Milky Way spirals boost Earth crust formation

Earth’s crust builds up faster when the Solar System surfs through one of four spiral arms of the Milky Way. Researchers measured the decay of uranium in the ancient continental crust in Greenland and Australia to study how it formed between 2.8 and 3.8 billion years ago. They found that, every 200 million years or so — in tune with Earth passing through the Milky Way — the rate of crustal production increased. One explanation could be that denser areas of the galaxy dislodge more comets from the Oort cloud, which rain down on Earth, melting the crust and causing more magma to bubble up and congeal.

Did this gene give modern human brains their edge?

Researchers have pinpointed a fateful genetic mutation that might have contributed to a cognitive advantage for modern humans over Neanderthals. Tests in the laboratory suggest that a single change in the gene TKTL1 ultimately causes the brain to develop more neurons. The Neanderthal version of TKTL1 still exists in some modern humans, although it’s very rare and it’s unknown whether it causes any disease or cognitive differences.

Blogger Comments:

Neanderthals had the larger brains, and all 'out of Africa' humans have Neanderthal ancestry.