Highlights of the North Autumn Sky

What can you see in the night sky this season? The featured graphic gives a few highlights for Earth’s northern hemisphere. Viewed as a clock face centered at the bottom, early (northern) autumn sky events fan out toward the left, while late autumn events are projected toward the right. Objects relatively close to Earth are illustrated, in general, as nearer to the cartoon figure with the telescope at the bottom center — although almost everything pictured can be seen without a telescope. As happens during any season, constellations appear the same year to year, and, as usual, the Leonids meteor shower will peak in mid-November. Also as usual, the International Space Station (ISS) can be seen, at times, as a bright spot drifting across the sky after sunset. Planets visible after sunset this autumn include Jupiter and Mars, and during late autumn, Saturn. [via NASA] https://ift.tt/2QUpFK9
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Rover 1A Hops on Asteroid Ryugu

Two small robots have begun hopping around the surface of asteroid Ryugu. The rovers, each the size of a small frying pan, move around the low gravity of kilometer-sized 162173 Ryugu by hopping, staying aloft for about 15 minutes and typically landing again several meters away. On Saturday, Rover 1A returned an early picture of its new home world, on the left, during one of its first hops. On Friday, lander MINERVA-II-1 detached from its mothership Hayabusa2, dropped Rovers 1A and 1B, and then landed on Ryugu. Studying Ryugu could tell humanity not only about Ryugu’s surface and interior, but about what materials were available in the early Solar System for the development of life. Two more hopping rovers are planned for release, and Hayabusa2 itself is scheduled to collect a surface sample from Ryugu and return it to Earth for detailed analysis before 2021. [via NASA] https://ift.tt/2NybBIq

Tuiteando al vuelo, September 23, 2018 at 04:27PM

El hilo de @javisalas ya es de por sí dolorosamente necesario, pero el de @Nopanaden es un perfecto complemento. Pero un complemento de verdad, de los que pueden ejercer acción sanadora en las conciencias, no es homeopatía. https://t.co/okGXgSJtSr

 

Tuiteando al vuelo, September 23, 2018 at 12:41PM

Más puntos de vista sobre la homeopatía. Médicos colegiados estafando a personas enfermas y llevándolas a la muerte. A propósito de un caso: https://t.co/Gdrl6kZ7wq
https://t.co/0lWbfwtIhd

Tuiteando al vuelo, September 23, 2018 at 12:29PM

Los jueces, como los médicos, tratan a diario con el sufrimiento de los otros. Muchas veces les juzgamos a la ligera (me incluyo y lo siento), está bien que recordemos cuáles son sus batallas. https://t.co/57pDdxCUqe

Equinox: Analemma over the Callanish Stones

Does the Sun return to the same spot on the sky every day at the same time? No. A more visual answer to that question is an analemma, a composite image taken from the same spot at the same time over the course of a year. The featured analemma was composed from images taken every few days at 4 pm near the village of Callanish in the Outer Hebrides in Scotland, UK. In the foreground are the Callanish Stones, a stone circle built around 2700 BC during humanity’s Bronze Age. It is not known if the placement of the Callanish Stones has or had astronomical significance. The ultimate causes for the figure-8 shape of this an all analemmas are the tilt of the Earth axis and the ellipticity of the Earth’s orbit around the Sun. At the solstices, the Sun will appear at the top or bottom of an analemma. Equinoxes, however, correspond to analemma middle points — not the intersection point. Today at 1:54 am (UT) is the equinox (“equal night”), when day and night are equal over all of planet Earth. Many cultures celebrate a change of season at an equinox. [via NASA] https://ift.tt/2xwcFCm

Window Seat over Hudson Bay

On the August 18 night flight from San Francisco to Zurich, a window seat offered this tantalizing view when curtains of light draped a colorful glow across the sky over Hudson Bay. Constructed by digitally stacking six short exposures made with a hand held camera, the scene records the shimmering aurora borealis or northern lights just as the approaching high altitude sunrise illuminated the northeastern horizon. It also caught the flash of a Perseid meteor streaking beneath the handle stars of the Big Dipper of the north. A few days past the meteor shower’s peak, its trail still points across the sky toward Perseus. Beautiful aurorae and shower meteors both occur in Earth’s upper atmosphere at altitudes of 100 kilometers or so, far above commercial airline fights. The aurora are caused by energetic charged particles from the magnetosphere, while meteors are trails of comet dust. [via NASA] https://ift.tt/2I5sIeB