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Featured Topic: Near Earth Objects

Courtesy NASA/JPL-Caltech The Oxford Dictionary of Astronomy defines a Near Earth Object (NEO) as "An asteroid whose orbit brings it close to Earth's orbit. Such Asteroids have a perihelion of less than 1.3 AU (1 AU = 149,597,870 km)".

Earth often has close encounters with these NEO's: there have been five in the last 10 years, such as the November 8, 2011 encounter with asteroid 2005 YU55, which came within 324,600 km of Earth. The last time a NEO of this size got this close was in 1989. As of April 2011, 7,954 NEO's have been discovered, this includes asteroids and comets. Of the 7,954, 1,047 have been listed as hazardous, but there is no need to worry! Approximately 1 NEO per year measuring 5-10m across strike the Earth, and in the last 100 years, only four NEO's have struck Earth with any considerable force. although these only affected the immediate area of the fall. The one with the highest chance of striking Earth has a probability of 1 in 300 and won't be near us till the year 2880.

Books:

Syndetics book coverWonders of the solar system / Brian Cox & Andrew Cohen.
"Employing his trademark clear, authoritative, yet down-to-earth approach, Brian will explore how these previously unseen phenomena have dramatically expanded our horizons with new discoveries about the planets, their moons and how they came to be the way they are." (Amazon.co.uk)
See also the DVD version

Syndetics book coverAsteroid rendezvous : NEAR Shoemaker's adventures at Eros / edited by Jim Bell and Jacqueline Mitton.
"An account of NASA's dramatic NEAR mission to the asteroid Eros by scientists involved." (Syndetics summary)

For more books try this search for 'Asteroids'.

From our databases:

For more articles please use our Science databases located here.

From the web

Pink & White Terraces

Dubbed the "Eighth Wonder of the Natural World", the Pink and White Terraces were formed over many thousands of years by silica-rich geothermal water flowing downhill from geysers next to Lake Rotomahana. While the White Terraces were by far the larger of the two, the Pink Terraces were the ones that were mainly used by tourists to bathe in.

Early in the morning of June 10th 1886 Mt Tarawera erupted, spewing hot mud, ash, and red-hot boulders into the air and burying several nearby villages and destroying the Terraces... or so everyone thought.

Earlier this year, a joint team of New Zealand and American scientists from GNS Science and Woods Hole Oceanographic Institution began a project to map the geothermal systems under Lake Rotomahana, using two autonomous underwater vehicles equipped with sonar. Quite by accident, they discovered the remains of the Terraces. The Pink Terraces were found in February, and the White in June.

Images

Before

These images are taken from: J Ernest Tinne, The Wonderland of the Antipodes and other sketches of travel in the North Island of New Zealand, Low and Searle, London, 1873.
Click the image for a larger picture

After

These images are taken from the Wellington City Libraries' photo collection.
Click the image for a larger picture

Books:

book jacket Tarawera : the destruction of the Pink and White Terraces, by Geoff Conly.
"One hundred and fifty-three people lost their lives when Mount Tarawera erupted early on the morning of 10 June 1886, and New Zealand's greatest tourist attraction, the spectacular Pink and White Terraces were destroyed in the violence of this country's worst recorded volcanic disaster." (from book jacket)

book jacket Tarawera and the terraces, by Philip Andrews.
"The eruption of Mt Tarawera on 10 June 1886 devastated the region and destroyed the pink and white terraces. This book records the history of the region and the details of the event. It is illustrated with contemporary photographs and reproductions of paintings. The author is a member of the Rotorua & District Historical Society. Second edition." (Syndetics summary)

For more books try this search for 'Tarawera Eruption'.

From our databases:

For more articles please use our Science databases located here

From the web

The GNS Science website have some good articles on the Pink and White Terraces.

Geology of Wellington

Faulting & Earthquakes

Wellington is home to three major fault lines, the Wairarapa Fault, Wellington Fault, and the Ohariu fault. While only one of these faults has moved during European settlement we can see the effect these faults have had on the landscape all over Wellington, for example the offset terraces in Harcourt Park and the raised beach terraces at Turakirae head are prime examples.

A few books I would recommend you look at for information on faulting in Wellington are:

Geology of the Wellington area / geology by J. Begg and C. Mazengarb.
This book has a good section on faulting and earthquakes in Wellington. It also has plenty of pictures.

On shaky ground : a geological guide to the Wellington metropolitan region / Graeme Stevens ; feature photography by LLoyd Homer ; landscape perspectives by Ron Brazier ; edited by David Heron.
On Shaky Ground explains faulting in Wellington in a very easy to understand manner. It also has a "Geological Tour" of Wellington in it, that points out all of the major faults and associated features.

For more library material please visit our Earthquakes page.

Major Surface Features

Wellington has so many geological surface features that it is hard to know where to begin listing them. So what I have done is to list out the ones that have information easily available at the library, we do have some information on other features not listed here, but these are the ones that have been studied, and written about a lot more.

Red Rocks:

This is possibly the most well know feature in Wellington. Good information can be found in these books:

Marine Terraces:

Wellington has several good places where you can view these terraces. All of them were formed by movement on the Wairapapa, or Wellington faults, and are quite useful in helping us understand how many times these faults have moved. Useful books are:

Peneplain Remnants:

Believe it or not, at one stage in its existence Wellington was a completely flat place. All the hills had been eroded down into a flat surface called a Peneplain. Then the faults around the region became much more active and uplift overtook erosion. The remnants of this surface can still be seen today as flat topped hills (e.g. Mt Kaukau, hence the name "K-surface"). Several books that may be useful are:

More...

All books on Wellington Geology live at the call number 559.314 in both the Lending and reference collections.

For more general books about New Zealand Geology, try this catalogue search.

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