Baby elephants are born big, standing approximately three feet (one meter) tall and weighing 200 pounds (91 kilograms) at birth.
Mother black bears are notoriously protective of their cubs, who stay with their mothers for about two years. Usually solitary animals, leopard cubs live with their mothers for two years, learning how to hunt. Bobcat kittens are born in litters of one to six and will stay with their mother for up to one year before heading off on their own. Dutiful mothers, female polar bears usually give birth to twin cubs, which stay with her for more than two years until they can hunt and survive on their own. Cheetah mothers typically give birth to a litter of three cubs, all of which will stay with her for one and a half to two years before venturing off on their own. The world’s top felines—including lions, tigers, cheetahs, and leopards—are slipping toward extinction. The Late Heavy Bombardment of Earth may have resulted from a dramatic disturbance of planetary orbits. Once Uranus and Neptune sweep most of the comets from their new orbits (and also switch places), the Late Heavy Bombardment ends.
The old models called orreries, like this 19th-century one in Northern Ireland, depicted a solar system that ran like clockwork. In a NASA clean room a scientist examines traps containing dust snared by the Stardust probe as it flew by the comet Wild 2.
Lunar gravity raises a tidal bulge on Earth; its spinning in turn accelerates the moon, causing it to spiral slowly outward. Tracked by telescopes and broadcast on TV, the impact of comet Shoemaker-Levy 9 in 1994 was vivid proof that the solar system is still violent—and that giant Jupiter shields Earth by vacuuming up comets. Vesta never grew into a planet, but it endured eons of impacts and is now, at more than 300 miles across, the third largest asteroid in the belt between Mars and Jupiter.
During the early chaos of the solar system, Jupiter is thought to have flung trillions of comets and perhaps a few planets into deep space. The endangered smalltooth sawfish, found in the Atlantic Ocean, can produce young without having sex first, a new study finds. A smalltooth sawfish rests on the seafloor off the coast of Florida's Everglades National Park.
Seven immature smalltooth sawfish likely entered the world in this way, according to a new study published Monday in the journal Current Biology. Virgin birtha€”also known as parthenogenesisa€”isn't unheard of in sharks, snakes, and even birds. The smalltooth sawfish, which can grow up to 20 feet (6 meters) in length, are listed as endangered by the United States.
Essentially, in virgin birth, a female is able to fertilize her own egg and produce offspring.
Although the sawfish pups aren't exact clones of their mother, says Fields, they get all of their genes from her, rather than half from her and half from a father.
The geneticist was a little surprised at first, but figured it made sense that parthenogenesis would occur in a species with low population numbers like the smalltooth sawfish.
Having a homogenous gene pool is deadly for a species with low population numbers, says George Burgess, director of the shark-research program at the Florida Museum of Natural History. The big question now, Fields says, is whether virgin births are more common among wild animal populations than researchers think.
Burgess, who wasn't involved in the study, isn't surprised that sawfish can reproduce this way. For now, Fields and colleagues are keeping an eye on the sawfish genetics samples that come in, looking for more evidence of virgin births and to see if the seven immature rays are still out there. The intricately shaped Cat's Eye nebula is formed from concentric gas bubbles and high-speed jets ejected from the outer layers of a dying star. This full-color map of Mars was created with Hubble images captured when the planet was at its closest approach to Earth.
A pulse of light emitted in 2002 from a red supergiant star called V838 Monocerotis illuminates a cloud of interstellar dust. Streams of charged particles blasted from the sun collide with Saturn's magnetic field, creating an aurora on the planet's south pole. A Hubble image of supernova 1987A shows a glowing wheel of debris ejected by a dying star some 20,000 years before it exploded. Two galaxies, known collectively as Arp 87, distort as their gravitational fields interact. A face-on view of the Messier 74 galaxy shows billions of stars forming within its spiral arms.


A view of Jupiter taken by Hubble in May 2008 shows a new red spot (far left) on the planet's storm-roiled surface. Three-dimensional computer-assisted reconstructions of Neanderthal infants based on fossils found in Russia and Syria (left) suggests that our closest human relatives had brains as large as ours at birth and larger than ours as adults.
The finding indicates that we and the Neanderthals inherited the pattern of early brain size and development from a yet unknown common human ancestor, researchers who did the reconstruction say.
Virtually nothing has been known about birth and early brain development in our fossil human relatives and ancestors, according to the researchers. In their paper, the researchers investigated birth and early brain development in the Neanderthals. What, according to the researchers, are some of the most relevant findings of the paper? Brain size at birth, a typically human feature, appears to be an old evolutionary achievement, inherited from a common ancestor.
After birth, Neanderthal brains grew faster than those of modern humans, but they had to reach larger adult brain sizes.
Supposedly they lived longer, had larger brains, and humans are an example of onwards and upwards evolution from this? This is a really good website but it needs more information like what was the brain size of a Neanderthal in ml or CC as they say now. National Geographic VoicesResearchers, conservationists, and others around the world share stories and commentary on the National Geographic Society's conversation platform Voices. Society Field Inspection 2016: Gulf of CaliforniaDescribed by Jacques Cousteau as the "aquarium of the world," the Gulf of California in Mexico is threatened by coastal development, climate change, and other human activities. Support National GeographicWe've supported more than 11,000 grants to scientists and others in the field.Learn more about our work.
Two years after being discovered deep in a South African cave, the 1,500 fossils excavated during the Rising Star Expedition have been identified as belonging to a previously unknown early human relative that National Geographic Explorer-in-Residence Lee Berger and team have named Homo naledi.
With at least 15 individuals of all ages and both sexes represented, the find adds an unprecedented amount of information to our understanding of early human evolution in Africa. In addition, the absence of any other animal remains or large debris in the fossil chamber strongly suggests that these non-human beings intentionally deposited their dead within this cave. BANABA ISLAND, Kiribati—Asbestos dust covers the floors of Banaba’s crumbling colonial houses, buildings, and schools. August 22, 2008—Several generations of stars "pose" for a family portrait amid curtains of clouds in the star-forming region called W5, about 6,500 light-years away. The composite image was released today to mark the upcoming five-year anniversary of the Spitzer Space Telescope, which lifted off from Cape Canaveral Air Force Station in Florida on August 25, 2003.
Since its launch, Spitzer's infrared images have been helping astronomers peer through gases and dust that can block visible light, revealing distant cosmic objects in high detail. The latest image of W5 uncovered a stellar family tree that offers scientists new evidence for the theory of triggered star formation.
Using Spitzer data, a team led by Xavier Koenig at the Harvard-Smithsonian Center for Astrophysics found that cavities in W5 do contain ladder-like progressions of stellar generations, with older stars (blue dots) inside the hollows and younger stars (pink and white dots) around the rims. Listen to your favorite National Geographic news daily, anytime, anywhere from your mobile phone. They nurse for two to three years, and are fully mature at 9 (females) to 15 (males) years of age.
After the eggs have incubated for about three months, the mother opens the nest and helps her young out of their shells. That led Neptune (foreground) and Uranus to disrupt a belt of comets, and Jupiter the asteroid belt. Jupiter’s gravity pumps Saturn closer to Uranus and Neptune, which drives them into the comet belt.
The real one is more random and sensitive to small changes in gravity: Moving a pencil across your desk today, says one astronomer, can shift Jupiter halfway around its orbit a billion years from now.
In February a 130-foot rock passed within 17,200 miles of Earth, closer than some satellites. Each speck left a hair-size track (right) as it plunged into the puffy aerogel at more than 13,000 miles an hour.
They grew to full size by absorbing rival planet embryos in a series of titanic collisions—one of which probably gave Earth its moon (below). Only lightly bound to the sun, they now form a spherical cloud, called the Oort cloud, around the solar system we know. Their orbits suggest that the cloud (seen here in cross section) is a spherical shell close to a light-year across, bisected by a donut. Though it's unknown how many individuals remain, scientists believe the population is less than 5 percent of its size at the time of European settlement in the U.S.


It occurs when material that's split off from an egg as it dividesa€”called a polar bodya€”fuses back with the egg. He was looking through a database of 190 smalltooth sawfishes tagged in southwestern Florida between 2004 and 2013 when he found something odd: Seven animals whose genes suggested they only had one parent. Low genetic diversity leaves a population more vulnerable to harmful mutations and less able to cope with environmental changes. But he's glad to have this added information about a species that scientists still know very little about. One theory is that the gases were released at 1,500-year intervals, giving the nebula its layered appearance.
The largest pillar (left) is an estimated four light-years long and, like its neighbors, is being bombarded by ultraviolet starlight that boils away gas on its surface and exposes the embryonic stars forming in its interior. More southerly regions are not visible because the north of the red planet was tilted toward Earth.
The dramatic whorls around the central star are trillions of miles across and were unknown to scientists until Hubble snapped this image in 2004. The ring, described as "cosmic pearls," is being illuminated by a shockwave of material emitted by the massive supernova explosion. The clusters of blue are young stars, and the pink areas indicate concentrations of ionized hydrogen. The new blemish, which appeared in spring of 2006, is significantly smaller than its older siblings, the Great Red Spot (center-right) and Red Spot Jr. The differences could have given modern humans an evolutionary advantage, the study indicates. Our newborns have an exceptionally large brain (400 cubic centimeters, like an adult chimp), which makes birth a difficult process,” University of Zurich scientists Marcia Ponce de Leon and Christoph Zollikofer said in notes accompanying a paper published today in the Proceedings of the National Academies of Science. They used computerized reconstruction to recover the morphology of the youngest known Neanderthal individuals: a newborn from Mezmaiskaya Cave (Crimea, Russia), and two infants from Dederiyeh Cave (Syria) with individual ages of 19 and 24 months at death, respectively.
This implies that most species-specific characteristics such as the Neanderthal’s heavy brow developed during embryonic and fetal development, rather than after birth.
The female Neanderthal pelvis was wider than in modern human females–but the head size of Neanderthal newborns was also larger. Posters and commenters are required to observe National Geographic's community rules and other terms of service. To learn firsthand what's going on in and around this marine treasure of global importance, the National Geographic Society sent its top scientists and officials to the region in January 2016. This is when powerful winds from massive stars carve out cavities inside nebulae, compressing gases along the rims of the cavities and spawning new stars. According to the Nice model (named for the French town where it was conceived), Jupiter, Saturn, Uranus, and Neptune had been born close together in the solar nebula, a disk-shaped cloud littered with rocky and icy debris.
In this view from the cloud, the sun and its familiar retinue are a small, bright swirl, and an undiscovered planet looms in the foreground.
It takes sawfish about seven years to become sexually mature, and the ones in the geneticist's study were born in 2011. With its relatively high brightness magnitude and at a distance of 28 million light-years from Earth, Messier 104, as Sombrero is more formally known, is easily viewed through a small telescope.
The stepped shape of this image is caused by the design of Hubble's Wide Field and Planetary Camera 2.
Scientists combined ultraviolet images of the auroras, taken by Hubble over a period of days, with visible-light images of the ringed planet.
Both galaxies are spiral-shaped and located about 300 million light-years from Earth in the constellation Leo.
Messier 74 is home to about a hundred billion stars, slightly fewer than the Milky Way has, and sits near the constellation Pisces some 32 million light-years away.
Careful study of visible-light images like this one and others taken in near-infrared light suggests that these red spot storms rise high above Jupiter's atmosphere.
They toured the desert islands off the southeastern coast of the Baja Peninsula and they listened to presentations by more than a dozen experts, including several whose Baja California research is funded by the Society.
In this view the aurora appears blue because of the ultraviolet camera, but a Saturn-based observer would see red light flashes.



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