How To Discover A Planet: A Short Step-by-step Guide On How Each Of Our Planetary Neighbors Were Originally

A boulder-strewn field of red rocks stretches across the horizon in this self-portrait of Viking 2 on Mars’ Utopian Plain. Viking 2 landed Sept. 3,1976, some 4,600 miles from the twin Viking 1 craft, which touched down on July 20.  

Image Credit: NASA/JPL

Should there be a holiday called Astronomy Day?

Where lights are to be turned off for the entire night so everyone could see the stars?

Observing the Ozone Hole from Space: A Science Success Story

Using our unique ability to view Earth from space, we are working together with NOAA to monitor an emerging success story – the shrinking ozone hole over Antarctica.

Thirty years ago, the nations of the world agreed to the landmark ‘Montreal Protocol on Substances that Deplete the Ozone Layer.’ The Protocol limited the release of ozone-depleting chlorofluorocarbons (CFCs) into the atmosphere.

Since the 1960s our scientists have worked with NOAA researchers to study the ozone layer. 

We use a combination of satellite, aircraft and balloon measurements of the atmosphere.

The ozone layer acts like a sunscreen for Earth, blocking harmful ultraviolet, or UV, rays emitted by the Sun.

In 1985, scientists first reported a hole forming in the ozone layer over Antarctica. It formed over Antarctica because the Earth’s atmospheric circulation traps air over Antarctica.  This air contains chlorine released from the CFCs and thus it rapidly depletes the ozone.

Because colder temperatures speed up the process of CFCs breaking up and releasing chlorine more quickly, the ozone hole fluctuates with temperature. The hole shrinks during the warmer summer months and grows larger during the southern winter. In September 2006, the ozone hole reached a record large extent.

But things have been improving in the 30 years since the Montreal Protocol. Thanks to the agreement, the concentration of CFCs in the atmosphere has been decreasing, and the ozone hole maximum has been smaller since 2006’s record.

That being said, the ozone hole still exists and fluctuates depending on temperature because CFCs have very long lifetimes. So, they still exist in our atmosphere and continue to deplete the ozone layer.

To get a view of what the ozone hole would have looked like if the world had not come to the agreement to limit CFCs, our scientists developed computer models. These show that by 2065, much of Earth would have had almost no ozone layer at all.

Luckily, the Montreal Protocol exists, and we’ve managed to save our protective ozone layer. Looking into the future, our scientists project that by 2065, the ozone hole will have returned to the same size it was thirty years ago.

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ON THIS DAY: An impressive impact crater on Mars, observed by NASA’s Mars Reconnaissance Orbiter, November 19, 2013. (NASA)

The missing links between galaxies have finally been found. This is the first detection of the roughly half of the normal matter in our universe – protons, neutrons and electrons – unaccounted for by previous observations of stars, galaxies and other bright objects in space.

Meteor impact craters of the world

Sequence of images of auroras seen at the south pole of Saturn. Images combine visible and ultraviolet light.

Credit: NASA, ESA, J. Clarke (Boston University, USA), and Z. Levay (STScI)

Comet Lovejoy is visible near Earth’s horizon in this nighttime image photographed by NASA astronaut Dan Burbank, Expedition 30 commander, onboard the International Space Station on Dec. 21, 2011.

Image credit: NASA

NGC 6960 (Western Veil nebula) & Horsehead Nebula and the Flame Nebula

by David Wills