From a record-setting black hole to the oldest animal DNA ever recovered, discoveries in 2021 stretched the limits of scientific study — and our imaginations.
Black holes
13 billion years ago, when the universe was a mere 670 million years old, a black hole was born. At a mass equal to 1.6 billion suns, the newly discovered supermassive black hole J0313-1806 is twice as heavy and 20 million years older than the previous record holder for oldest known black hole (SN: 2/13/21, p. 4). The ancient behemoth is so big that it challenges notions of how supermassive black holes first formed, astronomers say.
Object with mass has gravity too, according to both Isaac Newton and Albert Einstein, even if it’s barely noticeable. Scientists have now measured the gravity of a golf ball 2 millimeters wide and weighing about 90 milligrams — the smallest object ever to have its gravitational pull measured (SN: 4/10/21, p. 5). The tiny tug revealed that gravity behaves as predicted, even for very small masses. Researchers still want to test how gravity behaves on the even smaller quantum scale, where different rules of physics may apply.
A black hole has been seen gobbling up a neutron star, the collapsed remains of a dead supergiant star. Astronomers detected the event by measuring gravitational waves that emanated from the collision and eventually reached Earth (SN: 7/31/21, p. 6). All previously identified sources of these ripples in spacetime consisted of two like objects colliding, such as two neutron stars or two black holes.
A 160-million-year-old pterosaur nicknamed Monkey dactyl is now the earliest known animal with opposable thumbs (SN: 5/8/21 & 5/22/21, p. 16). The flying reptile, officially, may have used its thumbnails and flexible joints to clamber up and through trees in what is now northeastern China. The digits could have helped it capture insects and other prey, scientists say.
The tooth of a Siberian mammoth that lived more than a million years ago has offered up the oldest DNA ever recovered from an animal (SN: 3/13/21, p. 6). The previous record holder was 700,000-year-old DNA from a fossilized horse. Scientists say the new find probably approaches the limit of how long DNA can persist. Genes from the mammoth suggest that it may have belonged to a previously unknown species.
The mysterious hominid group known as the Denisovans died out long ago, but not without leaving a trace. The Indigenous Magnon people of the Philippines get about 5 percent of their DNA from Denison, a genetic analysis revealed (SN: 9/11/21, p. 16). That’s the highest level of Denison ancestry yet found anywhere in the world. Researchers are using the result, along with genetic clues from other groups that carry Denison DNA, to retrace Denison’ movements through Southeast Asia, Papua New Guinea and Australia.
The billionaire space race
Space made the headlines on many occasions in 2021: the landing of NASA, Perseverance rover on Mars, the arrival of a rare meteorite in the UK, the launch of a mission to hit an asteroid, the discovery of almost 200 new planets beyond the solar system – all shared their moment of fame with the public. However, the most extensive coverage of space news was probably of the 11-minute flight to outside the edge of Earth’s atmosphere made by William Shatner, AKA Captain James T Kirk of the USS Enterprise, in October 2021.
The flight was the second made by the New Shepard rocket, named in honor of the first American in space, Alan Shepard, and operated by Blue Origin, a company owned by Jeff Bezos. New Shepard’s first passenger flight in July 2021 carried Bezos and three others, but Richard Branson pipped Bezos to the post of being the first billionaire to make a space flight by taking off in Virgin Galactic’s rocket, Unity, nine days earlier. A back-and-forth bicker about whether Branson had been into space has rumbled along ever since. Branson’s flight only reached 55 miles above the Earth’s surface, so didn’t cross the Kármán line, the boundary above the surface that marks the edge of space. Bezos’s flight did.
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