SOLAR WINDS: THE MAGNETOSPHERE

Structure of the Magnetosphere

The Earth has a magnetic field with north and south poles. The magnetic field of the Earth is surrounded by the magnetosphere that keeps most of the particles from the Sun from hitting the Earth.

Some of these particles from the solar wind enter the atmosphere at one million miles per hour. We see them as one of the most beautiful of all natural phenomena -- Earth's polar lights, the aurora borealis in the north and the aurora australis, near the south pole.

The auroras occur when highly charged electrons from the solar wind interact with elements in the Earth's atmosphere and become trapped in the Earth's magnetic field. We see them as an undulating visual field of red, yellow, green, blue and purple dancing high in the Earth's atmosphere -- about 100 to 400 kilometers above us.

This image shows the parts of the magnetosphere. 1. Bow shock. 2. Magnetosheath. 3. Magnetopause. 4. Magnetosphere. 5. Northern tail lobe. 6. Southern tail lobe. 7. Plasmasphere.

Photo credit: Magnetosphere_Levels.jpg: Dennis Gallagherderivative work: Frédéric MICHEL - Magnetosphere_Levels.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9608059

FOSSILIZED WOOD: SILICATE REPLACEMENT

Fossilized Wood

Fossilized or petrified wood is amazing to behold in person. The original tree or branch is sometimes subjected to such a high degree of replacement that it is impossible to tell from the original at first glance. But fossilized it is.

All of the original cells are replaced one by one with minerals, often a silicate such as quartz, leaving the original cell structure intact. And while there is often amazing preservation of the big woody bits, the telltale leaves that help us identify that wood to species are often lost. If this is the case, we add our best guess at the genus and add xlon. So, Palmoxylon is the indeterminate wood of a palm, though we may never know which palm. If you have an interest in botany and fossils, you may want to consider making a career of it. The study of fossil wood is called palaeoxylology, with a palaeoxylologist being someone who studies fossil wood. Pretty cool, eh!

VICTORASPIS LONGICORNUALIS

This lovely specimen is an armoured agnatha jawless bony fish, Victoraspis longicornualis, from Lower Devonian deposits of Podolia, Ukraine.

Victoraspis longicornualis was named by Anders Carlsson and Henning Bloom back in 2008. The new osteostracan genus and species were described based on material from Rakovets' present-day Ukraine. This new taxon shares characteristics with the two genera Stensiopelta (Denison, 1951) and Zychaspis (Javier, 1985).

The Agnatha is a superclass of vertebrates. He looks quite different from our modern Agnatha, who include lamprey and hagfish. Ironically, hagfish are vertebrates who do not have vertebrae. Sometime in their evolution they lost them as they adapted to their environment.

Ref: Carlsson, A. & Blom, H. Paläont. Z. (2008) 82: 314. ttps://doi.org/10.1007/BF02988898

NORTH CASCADES NATIONAL PARK

North Cascades National Park / Rainforest Pool