Category Kids Queries

It is located in Santa Cruz, Argentina. It was painted 13,000 years ago. Profiles of human hands, perhaps created in some sort of coming-of-age ritual, join images of birds and beasts on the walls of this cave system in Patagonian wilderness at the tip of South America. Most of the hands are lefties, leading archaeologists to believe the ancient artists created their stencils by blowing paint through hollow bones held in their right hands.

It takes its name (Cave of the Hands) from the stencilled outlines of human hands in the cave, but there are also many depictions of animals, such as guanacos (Lama guanicoe ), still commonly found in the region, as well as hunting scenes that depict animals and human figures interacting in a dynamic and naturalistic manner. The entrance to the Cueva is screened by a rock wall covered by many hand stencils. Within the rock shelter itself there are five concentrations of rock art, later figures and motifs often superimposed upon those from earlier periods. The paintings were executed with natural mineral pigments – iron oxides (red and purple), kaolin (white), and natrojarosite (yellow), manganese oxide (black) – ground and mixed with some form of binder.

Picture Credit : Google

Ice Age beasts and geometric designs, hunting parties and herds of horses – the painted imagery of our ancestors took many shapes and styles. As far back as 41,000 years ago, working in the dim light of oil lamps, humans (and possibly our Neanderthal relatives) expressed themselves in caverns across the world with etchings and paintings. But while archaeologists know how Stone Age artists turned cave walls into canvasses – by using chisels, charcoal, berries, and even bat poop as paint applied with straw brushes or blown through hollow bones – no one knows for certain why they did it.

In the age before the written word, cave artists probably painted as a form of communication: to teach other members of their group about animals in the region and how to hunt them. Some archaeologists believe cave art may have served as a sort of magic. By painting animals and hunting scenes on the walls of scared caverns, or special caves used for ceremonies rather than as shelter, ancient artists may have hoped to bring success on the next hunt.

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In 2013, NASA announced its “Grand Challenge” to locate any nasty asteroids heading our way and prevent their impact. Rock-stopping options include:

Nuking it: Attack the asteroid with a nuclear missile, smashing it into space dust.

Ramming it: Launch a rocket directly into the asteroid to break it in half or divert its course.

Blasting it: Target the asteroid with a space-based laser to vaporize it before it gets too close.

Redirecting it: Mount rocket engines to the asteroid’s surface to change its course so it misses Earth.

Picture Credit : Google

Comets originate far out in the solar system – some from the Kuiper belt of icy bodies beyond the orbit of Neptune, and others from a more distant region known as the Oort Cloud.

Statistics imply that Oort Cloud may contain as many as a trillion comets and may account for a significant fraction of the mass of the solar system. However, since the individual comets are so small and so far away, we have no direct evidence about the actual existence of the Oort Cloud.

The Kuiper Belt is a disk-shaped region past the orbit of Neptune roughly 30 to 100 AU from the Sun. The Belt contains many icy bodies which can become comets. Occasionally the orbit of a Kuiper Belt object will be disturbed by gravitational interactions with the giant planets in such a way as to cause the object to take up an orbit that crosses into the inner solar system.

Although the Oort Cloud is much farther away from the Sun than the Kuiper Belt, it appears that the Oort Cloud objects were formed closer to the Sun than the Kuiper Belt objects. Small objects formed near the giant planets would have been ejected from the solar system by gravitational encounters. Those that didn’t escape entirely formed the distant Oort Cloud. Small objects that formed farther out had no such interactions, and remained as the Kuiper Belt objects.

Picture Credit : Google

Like asteroids, comets are leftovers from the formation of our solar system, but they’re made of different stuff. Each is an irregular ball of icy slush, frozen gases, and dark minerals just a few miles or kilometers wide. Like planets, some comets orbit the sun on a predictable schedule. Halley’s Comet, the most famous of these weird wanderers, drops by Earth every 76 years or so (it’s not due for its next visit until July 2061)

When the comet gets near the Sun, the Sun’s heat warms it, causing the ices to sublimate (turn directly from ice into steam), releasing also dust and rock from the nucleus. This creates both the coma (a thin atmosphere) surrounding the nucleus as well as the tail of material that generally streams from the nucleus away from the Sun. The size of the coma is thousands, hundreds of thousands, and sometimes millions of kilometers wide and the tail can reach tens of millions of kilometers long. Once the coma and tail form, they outshine and hide the true nucleus.

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California’s Death Valley holds the record for the highest reliably reported air temperature in the world, 56.7°C in July, 1913. In midsummer the desert region averages around 47°C and is the driest place in the US. Hardly the environment you would expect to find hiking trails, resorts, and a bewilderingly green golf course.

Ringed by mountains, Death Valley plunges to 86 metres below sea level, which helps explain the heat. It’s around a three-hour drive from Las Vegas.

Picture Credit : Google