Today is a historic day in astro science: NASA is crashing its $4 billion Cassini spacecraft into Saturn.
Instead of being left in orbit, and possibly crashing into one of Saturn’s moons, contaminating any life(!) that might be there, NASA has chosen this spectacular suicidal dive into Saturn’s atmosphere. After more than four years beyond its expected life time the spacecraft has no fuel left to adjust its course any longer.
At around 14 o’clock MET the Cassini spacecraft, which spent 20 years in space and has sent us amazing views of the Saturn system, will dive into Saturn’s atmosphere, sending final data for as long as possible before burning up like a meteor.
We all, working in our studios all day (and certain nights of course), may use a microwave oven to heat up a noodle soup or some sweet potatoes. While some of my caring friends insist I should not, I enjoy the convenience. But is it really save!?
When Neil Armstrong first walked on the moon in 1969, he carried a piece of muslin fabric from the left wing of the original 1903 Wright Flyer in his spacesuit pocket. There was also a piece of wood from the airplane’s left propeller.
The 1903 Wright Flyer was the first successful powered aircraft while the Apollo 11 spacecraft made the first manned mission to the moon.
"Phototaxis is an organism’s automatic movement toward or away from light. So a cockroach has negative phototaxis, because it’s always scuttling into dark corners while a moth has positive phototaxis because of it’s preference for bright lights.
Why are they attracted to bright lights?
We have several theories but no definite answers. Here are the theories:
Moths use the moon as a primary reference point to travel. So it’s attraction to the light maybe related to that orientation and cause disorientation.
Moths may see flying towards the light as advantageous and safer than flying somewhere dark.
Did you know moths are sensitive to ultra-violet light? A white light will attract more than than a yellow one."
In case you observe a strange, colorful vortex in the sky and think of an UFO, please read this before. :-)
"Twilight phenomenon is produced when unburned particles of missile or rocket propellant and water left in the vapor trail of a launch vehicle condenses, freezes and then expands in the less dense upper atmosphere. The exhaust plume, which is suspended against a dark sky is then illuminated by reflective high altitude sunlight, which produces a spectacular, colorful effect when seen at ground level. The phenomenon typically occurs with launches that take place either 30 to 60 minutes before sunrise or after sunset when a booster rocket or missile rises out of the darkness and into a sunlit area, relative to an observer’s perspective on the ground.
This phenomenon usually produces a cloud of green, blue, white and rose colored hues which takes on a corkscrew appearance as it is whipped around by wind currents. It is seen within two to three minutes after a launch has occurred. Depending on weather conditions, it could remain in the sky for up to half an hour before dispersing.
Pre-dawn launches are probably less spectacular than their dusk counterparts. During dusk launches, the sunlight shines through the exhaust plume. Pre-dawn launches, on the other hand, produce a more subtle display because the sunlight directly reflects off the plume."
"This is a remarkable record of the Sun's yearly journey through planet Earth's sky, made with planned multiple exposures captured on a single frame of a film. Exposures were made at the same time of day (9:00am local time), capturing the Sun's position on dates from January 7 through December 20, 2003. The multiple suns trace an intersecting curve known as an analemma."
An analemma is caused by the 23.5 degree tilt of the earth and the elliptical orbit.
Other planets produce, due to their different tilts and elliptical orbits, different looking analemmas. The image below is a simulation from Mars – called a Martian Analemma: "It shows the late afternoon Sun that would have been seen from the Sagan Memorial Station once every 30 Martian days beginning on Pathfinder's Sol 24 (July 29, 1997). Slightly less bright, the simulated Sun is only about two thirds the size as seen from Earth, while the Martian dust, responsible for the reddish sky of Mars, also scatters some blue light around the solar disk."