Hiding in Starlight

Total solar eclipses, like the one seen last month in North America, allow us to see details of the Sun that can't be seen at any other time. So, this month, The Sky at Night team looks at how scientists are creating eclipses on demand and discovering the secrets that can be revealed hidden in that starlight, including habitable planets like our own.
Maggie Aderin-Pocock travels to Belgium, where the European Space Agency's Proba-3 mission is going through its final testing stages. This groundbreaking mission aims to fly two satellites together in formation, with one satellite acting like the moon during an eclipse, blocking out the central light of the Sun. This allows the other satellite to image the corona, the Sun's outer atmosphere as seen during an eclipse. Maggie meets Dr Damien Galano from ESA, who tells her all about the challenges of the mission and what it hopes to achieve. Maggie then goes on to meet satellite operations test engineer Marie Beeckman, who takes her up close to the satellites to find out how the testing is going.
Meanwhile, Pete Lawrence is out and about in Bristol, meeting a team of scientists and amateur astronomers. He discovers how input from the amateurs was crucial to the discovery of two exoplanets colliding, which had caused the dimming of a star.
Finally, Chris Lintott is in Glasgow meeting Professor Beth Biller from Edinburgh University to discover why it is only by creating eclipses of distant stars that we could potentially find exoplanets more like our own.
And as ever, our resident astronomer, Pete Lawrence, guides us through what can be seen this coming month, with a particular focus on the rewards of viewing in daylight - but as always, he reminds us of the need to take care when doing this.

Human Landscapes and Practical Geology

Consider how to put your knowledge of geology to use. Issues faced by your community may benefit from geologic insights about groundwater, watersheds, roadways, pollution, and historic questions such as abandoned mines and quarries. Practical geology will only grow in importance as the world deals with climate change, resource shortages, and the pressing need to live in harmony with the planet.

Oil Geology Oil Plays and Oil Drilling

Trace the history of oil exploration and recovery, focusing on the geology of petroleum and natural gas formations. To strike oil, you need to find a source rock, a reservoir rock, a caprock, and a structural feature called a trap where oil can pool. Survey some of the world's most productive oil fields, and investigate the plusses and minuses of hydraulic fracturing, also known as "fracking."

Hunting Gold and Other Valuable Minerals

Mining is one of the oldest applications of practical geology. Find out how metals are classified and how most are associated with igneous and metamorphic deposits. Some metals, like gold, can be mined in a pure"nativestate that requires little processing. Discover how and where to go prospecting for gold, using the panning process perfected by the Forty-Niners in California.

Got Marble Non-Foliated Metamorphic Beauty

Turn to non-foliated metamorphic rocks, those without a distinctive mineral orientation. Investigate the different geologic conditions that create such rocks. Then survey a wide selection, spotlighting their beauty (marble), utility (soapstone), durability (quartzite), and economic value (banded iron formations). Professor Cotter discusses a few of his favorite metamorphic sites.

Metamorphic Rocks and Tectonic Features

Metamorphic rocks form under conditions halfway between those of sedimentary and igneous rocks. A good analogy is the process of glacier formation that turns snow into dense, interlocking crystals of ice. Focus on foliated metamorphic rocks, such as slate and gneiss, which have lineation patterns. Geologists can read these patterns to reconstruct ancient mountain ranges and plate boundaries.

Collecting Minerals and Crystals

Rocks are made up of minerals, which give rocks their immense variety. For example, the mineral quartz has the crystalline clarity of ice, while graphite is opaque and slippery, and pyrite has a metallic sheen. Most rocks are a mix of different minerals. Survey the most common types, analyze their chemistry and molecular structure, and learn how to identify them through a series of simple tests.

Lava Flows and Volcanic Landscapes

Learn what it's like to walk on barely cooled lava from an active volcanoone of many fascinating geologic experiences you can have in volcanic landscapes. Examine the different types of volcanoes and volcanic rocks, and which active sites are safe to explore and which you should avoid. In field geology you should be prepared, so review the special precautions to take when visiting volcanoes.

Medical Geology From Healthful to Harmful

Stressing that he is not a medical doctor, Professor Cotter delves into the healthful and harmful effects of geologically sourced substances. Some have proven benefits, such as antibacterial properties of salt and copper. Others can be deadly. For example, radon, a gaseous product of radioactive decay, causes lung cancer. Asbestos, a fibrous silicate mineral, is similarly dangerous to breathe.

The Siegfried Line

The formidable Seigried line, didn't come into play prior to Nazi Germany's invasion of France so it was substantially disassembled to build the Atlantic Wall. Five years later after D-Day Germany desperately attempted to refortify the decayed, disassembled and somewhat obsolete defenses. Battle focuses on Aachen where the allies employ withering fire power but become stalled leading Germany to squander its remaining military strength in the Battle of the Bulge leaving the Sigfried line open to a rapid crossing by the allies.

Axis Weapon The Kamikaze

As American naval forces hand Japan defeat after defeat Japan turns in desperation to the Kamikaze. The tactic proves effective against smaller ships but does not fails to sink a major vessel. Japan turns to an rocket propelled human guided bomb known as the Ohka and a torpedo know as the Kaiten. German considers a Kamikaze version of the V-1 rocket and later employs Kamikaze fighter attacks on Allied bombers.

Hitlers Megaships

In violation of the Treat of Versailles Hitler embarked on a program to build massive battleships but was only able to produce two; Bismarck and Tirpitz. To the frustration of his naval commanders Hiller found the ships far more valuable as propaganda weapons then warships. But they were obsolete almost as soon the they were launched and both succumbed to the emerging dominance of air power.

The SS

As Hitler's power grows within Nazi Germany, so does that of the SS. From its humble beginnings as Hitler's personal body guard, the SS under the leadership of Heinrich Himmler becomes a terrifying cult that engineers Hitler's vision for a new Germany. By the start of the war, the SS holds sway in politics, police and security and is responsible for the creation of the concentration camps. Its power, influence and terror spread with the creation of a military wing: the Waffen SS. By the end of the war, the SS has grown into a machine that controls of every aspect of the Third Reich and brutally disposes of any opposition to Hitler.

V1 Hitlers Vengeance Missile

In retaliation for devastating Allied bombing raids on German cities, Hitler orders the development of a groundbreaking weapon. This is the story of one of the most ambitious projects of the Third Reich: Hitler's Vengeance weapon, the V1. Though it was ready too late to make a difference to the outcome of the war, its legacy is the cruise missile a weapon that changed the face of war forever.

The Wolfs Lair

As European countries fall like dominoes to the all-conquering German armies, Hitler becomes convinced of his own military genius. He plans to invade Russia and orders the construction of a huge, heavily protected command complex of bunkers and buildings named the Wolfs Lair. But as he isolates himself in his concrete city, the war begins to slip from his grasp and a conspiracy is hatched to make the secret base his tomb.

How Soils Form and Erode

Soil may be the most important geologic resource on the planet. Discover how geologists classify soils, focusing on the concept of soil horizons, which are distinct layers that often vary in composition, color, and texture. Analyze how this cross section, which signals soil fertility, differs depending on the type of biome. Learn how soils form and how easily they are destroyed by erosion.

Groundwater and Water Wells

Dig into the mystery of groundwater. Apart from sinkholes and caves, there are no underground lakes or rivers. Instead, water fills the voids in porous rocks below a certain depth, called the water table. Discover how wells are dug and why it's a waste of money to hire a dowser, since water is practically everywhere if you dig deep enough. Also, consider the problem of groundwater pollution.

Granite Igneous Rocks That Form at Depth

Having studied igneous rocks that cool quickly, now turn to igneous rocks that cool deep underground over the course of millions of years. Find out how to distinguish granite from diorite, gabbro, and other intrusive igneous rocks. Learn about notable batholiths, such as Yosemite's Half Dome, and look at the abundant uses for granite and similar rocks.