"MISSING LINK" : New Fossil Links Humans, Lemurs?

Meet "Ida," the small "missing link" found in Germany that's created a big media splash and will likely continue to make waves among those who study human origins.

In a new book, documentary, and promotional Web site, paleontologist Jorn Hurum, who led the team that analyzed the 47-million-year-old fossil seen above, suggests Ida is a critical missing-link species in primate evolution (interactive guide to human evolution from National Geographic magazine).

(Among the team members was University of Michigan paleontologist Philip Gingerich, a member of the Committee for Research and Exploration of the National Geographic Society, which owns National Geographic News.)

The fossil, he says, bridges the evolutionary split between higher primates such as monkeys, apes, and humans and their more distant relatives such as lemurs.

"This is the first link to all humans," Hurum, of the Natural History Museum in Oslo, Norway, said in a statement. Ida represents "the closest thing we can get to a direct ancestor."

Ida, properly known as Darwinius masillae, has a unique anatomy. The lemur-like skeleton features primate-like characteristics, including grasping hands, opposable thumbs, clawless digits with nails, and relatively short limbs.

"This specimen looks like a really early fossil monkey that belongs to the group that includes us," said Brian Richmond, a biological anthropologist at George Washington University in Washington, D.C., who was not involved in the study, published this week in the journal PLoS ONE.

But there's a big gap in the fossil record from this time period, Richmond noted. Researchers are unsure when and where the primate group that includes monkeys, apes, and humans split from the other group of primates that includes lemurs.

"[Ida] is one of the important branching points on the evolutionary tree," Richmond said, "but it's not the only branching point."

At least one aspect of Ida is unquestionably unique: her incredible preservation, unheard of in specimens from the Eocene era, when early primates underwent a period of rapid evolution. (Explore a prehistoric time line.)

"From this time period there are very few fossils, and they tend to be an isolated tooth here or maybe a tailbone there," Richmond explained. "So you can't say a whole lot of what that [type of fossil] represents in terms of evolutionary history or biology."

In Ida's case, scientists were able to examine fossil evidence of fur and soft tissue and even picked through the remains of her last meal: fruits, seeds, and leaves.

What's more, the newly described "missing link" was found in Germany's Messel Pit. Ida's European origins are intriguing, Richmond said, because they could suggest—contrary to common assumptions—that the continent was an important area for primate evolutio

Particles Larger Than Galaxies Fill the Universe?

Charles Q. Choi
for National Geographic News

June 2, 2009

The oldest of the subatomic particles called neutrinos might each encompass a space larger than thousands of galaxies, new simulations suggest.

Neutrinos as we know them today are created by nuclear reactions or radioactive decay.

According to quantum mechanics, the "size" of a particle such as a neutrino is defined by a fuzzy range of possible locations. We can only detect these particles when they interact with something such as an atom, which collapses that range into a single point in space and time.

For neutrinos created recently, the ranges they can exist in are very, very small.

But over the roughly 13.7-billion-year lifetime of the cosmos, "relic" neutrinos have been stretched out by the expansion of the universe, enlarging the range in which each neutrino can exist.

"We're talking maybe up to roughly ten billion light-years" for each neutrino, said study co-author George Fuller of the University of California, San Diego.

"That's nearly on the order of the size of the observable universe."

"Small" Physics, Writ Large

Neutrinos have no charge, and their masses are so tiny they have yet to be accurately measured.

This means that neutrinos, which zip around at nearly the speed of light, can pass through normal matter largely undisturbed.

Most neutrinos that affect Earth come from the sun. Billions of solar neutrinos pass through the average human every second.

While trying to calculate masses for neutrinos, Fuller and his student Chad Kishimoto found that, as the universe has expanded, the fabric of space-time has been tugging at ancient neutrinos, stretching the particles' ranges over vast distances.

Such large ranges can remain intact, the scientists suggest in the May 22 issue of Physical Review Letters, since neutrinos pass right through most of the universe's matter. An open question is whether gravity—say, the pull from an entire galaxy—can force a meganeutrino to collapse down to a single location.

"Quantum mechanics was intended to describe the universe on the smallest of scales, and now here we're talking about how it works on the largest scales in the universe," Kishimoto said.

"We're talking about physics that hasn't been explored before."

According to physicist Adrian Lee at the University of California, Berkeley, who was not part of the study team, "gravity is a real frontier these days that we don't really understand.

"These neutrinos could be a path to something deeper in our understanding with gravity."

(Related: "At Ten, Dark Energy 'Most Profound Problem' in Physics.")

Follow the Gravity?

But answers to such questions depend on eventually detecting these predicted meganeutrinos.

Although they should be extraordinarily common in the universe, the relic neutrinos now have only about one ten-billionth of the energy of neutrinos generated by the sun.

"This makes relic neutrinos near impossible to detect directly, at least with anything one could build on Earth," study co-author Fuller said.

Still, the fact that there are so many relic neutrinos means that together they likely exert a significant gravitational pull—"enough to be important for how the universe as a whole behaves," Fuller added.

Dark matter, for example, has never been directly observed. But astrophysicists have found proof that dark matter exists based on its effect on colliding galaxies.

"So by looking at the growth of structures in the universe," Fuller said, "you might be able to detect relic neutrinos indirectly by their gravity."

Penguins Underwater, Antarctica

Penguins surface near an air hole in Antarctica, captured with a remote underwater camera.

Asperatus

Norii au fost văzuţi în mai multe regiuni din Marea Britanie, dar şi în Noua Zeelandă. De obicei, aceste formaţiuni se risipesc fără să cauzeze furtuni. Experţii de la Societatea Meteorologică Regală (RMS) din Marea Britanie intenţionează să îi numească "Asperatus", însă nu au încă suficiente date pentru a-i clasifica. Aceasta ar putea fi prima varietate de formaţiune noroasă etichetată după mai mult de jumătate de secol.

"Este ca şi cum te-ai uita la o mare învolburată, de sub apă", spune Gavin Pretor-Pinney, fondator al unei societăţi ce se ocupă cu studiul norilor, citat de dailymail.co.uk. "Încercăm să identificăm toate imaginile pe care le primim, dar sunt câteva care pur şi simplu nu se încadrează în nicio categorie", adaugă el.

Societatea Meteorologică Regală strânge informaţii cu privire la locaţiile exacte şi datele la care au fost observaţi aceşti nori, pentru a înţelege cum se formează. "Probabil că se formează în condiţii de temperaturi ridicate. Este nevoie de multă energie pentru a rezulta forme atât de dramatice. Culorile întunecate sugerează că acest tip de nori înglobează o cantitate mare de apă", explică profesorul paul Hardaker, preşedinte executiv al RMS.

Clasificarea oficială a unui nou tip de nori se face de către Organizaţia Internaţională de Meteorologie, ce funcţionează sub egida Naţiunilor Unite, care trebuie să aprobe includerea acestuia într-un atlas folosit ca reper de specialiştii din jurul lumii.