Our closest worm kin regrow body parts, raising hopes of regeneration in humans
What if humans could regrow an amputated arm or leg, or completely restore nervous system function after a spinal cord injury?
A new study of one of our closest invertebrate relatives, the acorn worm, reveals that this feat might one day be possible. Acorn worms burrow in the sand around coral reefs, but their ancestral relationship to chordates means they have a genetic makeup and body plan surprisingly similar to ours.
Earth and stars as seen from the International Space Station, 17 May 2016. Photograph: Nasa/Rex/Shutterstock
The universe is expanding faster than anyone had previously measured or calculated from theory. This is a discovery that could test part of Albert Einstein’s theory of relativity, a pillar of cosmology that has withstood challenges for a century.
Nasa and the European Space Agency jointly announced the universe is expanding 5% to 9% faster than predicted, a finding they reached after using the Hubble space telescope to measure the distance to stars in 19 galaxies beyond theMilky Way.
In a dingy apartment building, insulated by layers of hanging rugs, the last family on Earth huddles around a fire, melting a pot of oxygen. Ripped from the sun’s warmth by a rogue dark star, the planet has been exiled to the cold outer reaches of the solar system. The lone clan of survivors must venture out into the endless night to harvest frozen atmospheric gases that have piled up like snow.
As end-of-humanity scenarios go, that bleak vision from Fritz Leiber’s 1951 short story “A Pail of Air” is a fairly remote possibility. Scholars who ponder such things think a self-induced catastrophe such as nuclear war or a bioengineered pandemic is most likely to do us in. However, a number of other extreme natural hazards—including threats from space and geologic upheavals here on Earth—could still derail life as we know it, unraveling advanced civilization, wiping out billions of people, or potentially even exterminating our species.
Yet there’s been surprisingly little research on the subject, says Anders Sandberg, a catastrophe researcher at the University of Oxford’s Future of Humanity Institute in the United Kingdom. Last he checked, “there are more papers about dung beetle reproduction than human extinction,” he says. “We might have our priorities slightly wrong.”
Frequent, moderately severe disasters such as earthquakes attract far more funding than low-probability apocalyptic ones. Prejudice may also be at work; for instance, scientists who pioneered studies of asteroid and comet impacts complained about confronting a pervasive “giggle factor.” Consciously or unconsciously, Sandberg says, many researchers consider catastrophic risks the province of fiction or fantasy—not serious science.
A fresh set of estimates by biologists now suggests that species with backbones are starting to vanish quicker compared to the time since dinosaurs became extinct. The situation has got so bad that human beings are now endangered as well. Paul Ehlirch is a researcher from Stanford University who stated that the study clearly shows that the world has now entered the 6th mass extinction event. It turns out that this event was triggered by humans.
Biologists are known to have believed that planet Earth is in the midst of a great extinction event. Critics have made the argument that the estimates somewhat overstate the actual facts on the matter. Scientists usually compare the extinction rate to the background extinction rate in order to figure out what a major extinction event is. Just so that it is clear, background extinction rate is the rate at which one expects species to vanish fro the face of the Earth.