Where did the moon come from? What is it made of? And what events created the distinctive pattern of light and dark on its surface? To find out, we have sent satellites out to crash onto its surface, astronauts to comb its craters and hillsides and collect rocks, and high-tech spacecraft to map its nooks and crannies.

A half-century of study has brought us closer to the answers. Many scientists now believe that the moon was born in a monumental collision between Earth and a Mars-sized body early in the history of the solar system, some 4.5 billion years ago.

From the remains of the impact, a giant ball of magma coalesced in Earth orbit. Gravity sculpted this hot mass into a sphere. In time, its surface cooled, forming a hard crust with magma just underneath.

Around 4.3 billion years ago, a giant impact battered the moon’s south pole, sending debris as far as the opposite side of the moon. The impact formed the Aitken basin. At roughly 2,500 kilometers in diameter and 13 kilometers deep, it is one of the largest known impact craters in the Solar System.

Its formation marked the beginning of a period of large-scale changes to Continue reading The Moon Battered by Impacts →

News from the Hubble Space Telescope, and Hubblecast. The great observatory has observed the variable star RS Puppis over a period of five weeks, showing the star growing brighter and dimmer. These pulsations have created a stunning example of a phenomenon known as a light echo, where light appears to reverberate through the murky environment around the star.

A pulsating star forms when most of its hydrogen fuel has been consumed. It then becomes unstable, expanding and shrinking over a number of days or weeks and growing brighter and dimmer as they do so.

A new Hubble image shows RS Puppis, a type of variable star known as a Cepheid variable. As variable stars go, Cepheids have comparatively long periods. RS Puppis, for example, varies in brightness by almost a factor of five every 40 or so days.

RS Puppis is enshrouded by a nebula — thick, dark clouds of gas and dust. Hubble observed this star and its murky environment over a period of five weeks in 2010, capturing snapshots at different stages in its cycle and enabling scientists to create a time-lapse video of this ethereal object.

The apparent motion shown in these Hubble observations is an example of a phenomenon known Continue reading Strange Case of the Pulsating Star →

Approximately every 11 years, the solar cycle puts our sun into a rage of incredible solar activity. Coronal mass ejections and solar flares are just some of the phenomena that occur on our sun’s violent surface. However, something is happening that is not so visible; magnetic changes are actually causing the the sun’s poles to swap.

Our sun is an incredible fusion engine. From the surface of earth, we see it as a mere ball of light, but through amazing high-res imaging capabilities, we can observe real solar activities thanks to NASA’s Solar Dynamics Observatory.

This video is adapted from an intriguing episode of Hubblecast. nature’s telescopes. It explores a phenomenon called gravitational lensing. The gravitational force of a galaxy, full of stars, gas, dark matter, and dust, is so enormous that it affects the region it sits in and distorts the very fabric of the surrounding space.

It isn’t only galaxies that do this. Any object that has mass distorts the space around it with its gravity, from large galaxy clusters down to individual stars. In space, light travels invariably along straight lines. But what is a straight line? Well, it is the shortest distance between two points. But in a curved space, the shortest distance between two points may not look particularly straight to us.

Now what that means is that when light passes very near by a massive object that curves the space around it, the light ray is bent. As a result, this massive object, or rather the curved space around it produced by its gravity, acts like a lens; a gravitational lens that deflects light into our telescopes that would have otherwise never made it there.

This deflection means that distant and faint objects can suddenly be seen peeking from around the edge Continue reading Einstein’s Rings and the Fabric of Space →

Hurricanes, typhoons, tropical cyclones: they are creatures of tropical seas, sweeping up heat laden waters, converting it to wind, rain, and waves. Why do a rare few evolve into colossal monsters, that leave in their wake a trail of destruction, death, and despair? Do we now face a rising tide of Super Hurricanes and Typhoons?

One reason is that more and more people are moving to coastlines around the world, drawn by a combination of jobs and lifestyle. In the United States, for example, 39% of the population lives in coastal counties.

A Columbia University report takes a global look at this trend by identifying major disaster hot spots: the east coast of North America, Bangladesh, the Philippines, the east coast of China. These hurricane-prone coastlines, with their dense population centers, hold enormous potential for economic loss and loss of life.

To make matters worse, the oceans have gotten steadily warmer over the last few decades, adding potency to the hurricane’s fuel. Sea levels are expected to rise by as much as a meter by the end of the century, increasing the risks of storm surge.

As more people pack the coastlines, man and nature are in the midst of an excrutiating Continue reading Super Hurricanes and Typhoons →

Join the scientists who manage Curiosity’s journey to Mt. Sharp in reveling in its ongoing discoveries. Find out what the rover is looking for, how it’s navigating the rocky terrain, and what ultimately the journey means to its human patrons. It’s one of the most sophisticated, and inspiring, missions ever undertaken to another planet. Video from NASA/JPL.

Our latest episode of Cosmic Journeys, coming soon. This video asks: what are the conditions that can turn an average tropical storm into a destructive monster? While scientists work to identify the diagnostics of super hurricanes and typhoons, they face an escalating conflict between man and nature. More and more of the world’s people are living in proximity to the sea, making them vulnerable to ocean storms. At the same time, the oceans are getting warmer and sea levels are rising, potentially raising the destructive potential of powerful hurricanes and typhoons.

News from NASA on the upcoming Mars mission, MAVEN. While Mars Rover Curiosity is studying the Red Planet from the ground, the Maven satellite will give us important data taken from the upper atmosphere. Was Mars ever full of water, and as lush as the forests of Earth? By studying various atomic and molecular processes, Maven will help to decipher the mysterious history of Mars.

Two teams of astronomers probe the galactic center for proof that a supermassive black holes lies within it. Is this monster of the milky way biding its time till its next outburst, or has it gone dormant?