The Year in Abstracts: Obese Genomes and Banana Galaxies
Welcome back to a very special holiday edition of the Abstract! I hope this week brought you all the seasonal mirth to which you are entitled.
As the year winds to a close, I’m sharing five studies that stood out to me in 2024. They are not judged by any specific criteria other than general mind bogglery. We’ll start with banana galaxies; no further explanation needed. Then, the new record-holders for brightest thingummy and biggest genome. Next, we are living in an RNA world and we are all RNA girls. And to close out 2024, a vision of life in the lunar underground.
It’s Bananas All the Way Down
The James Webb Space Telescope, launched on Christmas Day 2021, has been looking at weird space stuff for over two years now, yielding a constant stream of insights about the early universe, alien exoplanets, and whatever else it sets its unprecedented sights on.
To that end, 2024 kicked off with the landmark discovery that baby galaxies from the dawn of time were…bananas. Scientists reported in January that galaxies at high redshifts—meaning they were observed in the very ancient universe—often seem to take on a “banana-like” shape.
“In this paper, we place new constraints on the 3D shapes of high-redshift galaxies using JWST observations from the Cosmic Evolution Early Release Science (CEERS) survey,” said researchers led by Viraj Pandya of Columbia University. “We will illustrate how this curved ‘banana-like’ joint distribution” arises from galaxies “with intrinsically elongated 3D shapes.”
The results suggest that many galaxies go through an awkward “prolate” phase of morphological elongation before maturing into more familiar galactic shapes we see today, like clusters and disks. And while Pandya and his colleagues see bananas in space, these shapes have also been described as pickles or cigars. It all depends on what kind of treat you want to see at the edge of the universe.
A Sun a Day Keeps the Doctor Away
2024 had its fair share of dark moments, but there was one very literal bright spot: Scientists identified the most radiant object known in the universe, which is a quasar called J0529−4351. Quasars are pyrotechnic galactic cores and the most ludicrously luminous entities in space. Their “implausibly huge output of light,” as it is described in the above study, is generated by intense gravitational interactions between supermassive black holes at the center of galaxies, and forms of matter (gas, dust, doomed civilizations) that accrete around those holes.
“In terms of luminosity and likely growth rate, J0529−4351 is the most extreme quasar known,” said researchers led by Christian Wolf of Australian National University. “The black hole in this quasar accretes around one solar mass per day onto an existing mass of ∼17 billion solar masses.”
In other words, J0529−4351 is eating the equivalent of a whole Sun every single day. It’s the Gaston of quasars. As a consequence of this insane diet, J0529−4351 is 500 trillion times more luminous than the Sun. Just utterly incomprehensible radiance. What’s wild is that the record for brightest quasar has been repeatedly broken in recent years, so it’s possible that even J0529−4351—an unprecedented light-barfing marvel—may be outshone in the near future.
Big Genome Energy
Fernández, Pol et al. "A 160 Gbp fork fern genome shatters size record for eukaryotes." Cell.
Pop quiz: What species has the biggest genome ever found? You would be forgiven for not guessing that it is (drumroll) some random fern in New Caledonia. And yet, in May, scientists reported that Tmesipteris oblanceolata, a tropical fork fern that appears totally inconspicuous, bears the most “obese genome” ever discovered.
The fern’s genome contains 160 billion base pairs, making it 50 times bigger than a human genome and 7 percent bigger than the genome of the Japanese andromeda, a flowering plant that previously held the record.
“Here, we present the discovery of the largest eukaryotic genome so far reported,” said researchers led by Pol Fernández of the Institut Botanic de Barcelona. “This record-breaking genome challenges current understanding and opens new avenues to explore the evolutionary dynamics of genomic gigantism.”
“It cannot be completely ruled out that even larger genomes may be uncovered in the future,” the team concluded. “Nevertheless, the multiple physiological, ecological, and evolutionary costs associated with genomic expansions at such gigantic scales most likely suggest that if the upper limit has not been reached yet, that of Tmesipteris oblanceolata must be very close to it.”
In other words, this species may well be the world's genomic heavyweight champion. And it’s just some tropical fern! Nature: an inscrutable weirdo.
It’s a Mad (RNA) World
How did life first arise on Earth? There are lots of compelling mythological answers to this question, such as “the Sky and Earth Hooked Up” and “Magic Dirt.” The question has also inspired a number of tantalizing scientific hypotheses, including what’s known as “RNA World.” In this leading scenario, the first Earthlings were self-replicating molecules of ribonucleic acid (RNA) that emerged about four billion years ago, before the emergence of proteins or deoxyribonucleic acid (DNA).
In March, scientists bolstered support for RNA World by developing an RNA enzyme that can perform some of the functions associated with these early speculative molecules, including making accurate copies of RNA strands and introducing variants over time. This discovery is a stepping stone toward recreating forms of primordial evolution in laboratory conditions, where they can be directly probed for clues about the origins of life, known as abiogenesis.
“At some point during the early history of RNA-based evolution, it is thought that RNA evolved the ability to catalyze its own replication, acting as an RNA-dependent RNA polymerase,” said researchers led by Nikolaos Papastavrou of the Salk Institute for Biological Studies. “This study demonstrates the critical importance of replication fidelity for maintaining heritable information in an RNA-based evolving system, such as is thought to have existed during the early history of life on Earth.”
The study offers a new piece of a puzzle that has enraptured untold generations: How can life spring up from non-living materials? What kind of cosmic magic trick is that? Enchanted dirt may genuinely not be far off from the truth, in the end.
You Can Take the Human Out of the Cave, But…
Humans simply cannot resist a cozy cave. Caves were our starter homes; spaces used not just as shelters but as canvases for our imaginations and hubs of social and ritual activity (see: tortoise parties). So perhaps it’s no surprise that as we expand our exploratory efforts into outer space, we still cannot pass up a snug subterranean pad, even if it is on the Moon.
To that end, scientists reported in July that the Mare Tranquillitatis pit (MPT), a 330-foot-deep opening about 250 miles away from the Apollo 11 landing site, may be the entrance to an underground cave system made of ancient lava tubes. The team was able to map out this structure, which is the deepest known pit on the Moon, with radar reflections from NASA’s Lunar Reconnaissance Orbiter.
“We find that a portion of the radar reflections originating from the MTP can be attributed to a subsurface cave conduit tens of metres long, suggesting that the MTP leads to an accessible cave conduit beneath the Moon’s surface,” said researchers led by Leonardo Carrer of the University of Trento. “This discovery suggests that the MTP is a promising site for a lunar base, as it offers shelter from the harsh surface environment and could support long-term human exploration of the Moon.”
It would be hilarious if all of those lofty human aspirations of a spacefaring techno-utopia culminated in us becoming cavemen again, just on a different world. The study also gets extra points for occasionally sounding like a high-end real estate listing, describing the pit as “an elliptical skylight with vertical or overhanging walls and a sloping pit floor that seems to extend further underground.” Dang, finally a Moon cave with the right specs—though it comes unfurnished and lacks desirable amenities (including breathable air). Who’s up for some space spelunking?
That’s a wrap on the Abstract for 2024. Thanks so much for reading, and Happy New Year!