Every 62 million years there is a mass extinction on Earth. No one is sure why but, since the solar motion through the Milky Way has been computed for the past 600 million years, we know it is too long a cycle for it to be a product of our solar system. A new paper theorizes this is because the earth begins to ... wobble ... due to solar oscillations and that wobbling happens on a predictable timetable.

They call it galactic shock due to cosmic ray modulation and its presence at those times impacts biological diversity - that means extinction and origination. The physicists, Mikhail V. Medvedev and Adrian L. Melott of the University of Kansas, say this has happened for the last half billion years. How much impact? As much as 10% of life on earth.

Why a wobble?

A recent UN study, Livestock's Long Shadow, basically says you can help the environment more by driving than walking.

A long-held belief in theories of human behavior is that people want to feel good and avoid feeling bad.

Nothing in that principle explains why people enjoy horror movies or, additionally, why they pay for the privilege of being scared.

Investigators generally use one of two theories to explain why people like horror movies:

1. It's excitement, not fear. People aren't actually afraid, they get a surge from the action and suspense.

2. Terror now brings euphoria later. Think you had a bad day at the office? Imagine being chased by zombies. It always feels better to know someone else is being chased by zombies.

You don't need a big brain, or a high IQ, to have a comfortable life and a good family.

Witness the case of this French civil servant, written about by Dr. Lionel Fuillet in The Lancet. At age six months he was treated for hydrocephalus (water on the brain) with a shunt in his head to drain away the fluid. At age 14 he complained of unsteadiness and left leg weakness, which cleared up after the shunt was adjusted. Beyond that his neurological development and medical history were normal.

At age 44 the leg weakness returned and he was treated by Dr. Feuillet and colleagues of the Hôpital de la Timone and Faculté de Médecine, Université de la Méditerranée, Marseille, France.

If you've never heard of Lake Agassiz, it's no surprise. It disappeared over 8,000 years ago. Yet it may have been the global warming trigger that ended the last Ice Age.

Using remains from lakes, bogs and channels, a multi-disciplinary group of scientists recently tackled the secrets of glacial Lake Agassiz and Big Stone Moraine.

Knowing the chronology of glacier retreat, and when glacial lakes formed, is important in linking physical events on the landscape with paleoclimate records. At the close of the last ice age, glacial ice in the upper Midwest of the United States retreated very quickly, likely in response to the warming climate.