The cynical answer is just two words....
...we are.
'New data has revealed that the heliosphere, the protective shield of energy that surrounds our solar system, has weakened by 25 per cent over the past decade and is now at it lowest level since the space race began 50 years ago.
Scientists are baffled at what could be causing the barrier to shrink in this way and are to launch mission to study the heliosphere.
The Interstellar Boundary Explorer, or IBEX, will be launched from an aircraft on Sunday on a Pegasus rocket into an orbit 150,000 miles above the Earth where it will "listen" for the shock wave that forms as our solar system meets the interstellar radiation.
The epidermis or top layer of skin contains three different types of cells: squamous cells, basal cells and melanocytes. Skin cancer is a disease of the body's skin cells caused mainly by overexposure to ultraviolet (UV) radiation.
Honey Bee Senses
Posted at: July 3, 2002 09:39 AM | Comments (0) | Edit
Vision
The individual light sensors which make up the compound eyes of insects are called "ommatidia". Each eye of the honeybee has 4500 ommatidia, all of which collect light from slightly different directions. From this mosaic of light sensors a complete image is pieced together. 4500 light sensitive units is a relatively small number compared to, say, the number of photoreceptors in the human retina (1.5 million), or elements in a current state-of-the-art digital camera (3 million). Hence the image that the honeybee sees is of very low resolution.
Each ommatidium contains nine light sensitive cells. Two of these are receptive to green light, two to blue light, and two to ultra violet light.
Solar irradiance variations below 300 nm, although it represents only 1% of the Sun's total electromagnetic output, are especially important since the irradiance is totally absorbed in various layers of Earth's atmosphere. Consequently, it plays a significant role in heating Earth's atmosphere and establishing its chemical composition through photodissociation and photoionization processes. The UV irradiance between 200 and 285 nm penetrates to the stratosphere and is the major source of the stratospheric heating and the ozone photodissociation. Radiation between 165 and 205 nm photodissociates the oxygen molecules and other important odd oxygen constituents of the stratosphere and the mesosphere.
Light scattering pigment powder particles, surface treated to minimize inparticle cohesive forces, are dispensed from a jet mill deagglomerator as separate single particles to produce a powder contrail having maximum visibility or radiation scattering ability for a given weight material.