Orion in Depth

Orion is a familiar constellation. The apparent positions of its stars in two dimensions create a well-known pattern on the bowl of planet Earth’s night sky. Orion may not look quite so familiar in this 3D view though. The illustration reconstructs the relative positions of Orion’s bright stars, including data from the Hipparcus catalog of parallax distances. The most distant star shown is Alnilam. The middle one in the projected line of three that make up Orion’s belt when viewed from planet Earth, Alnilam is nearly 2,000 light-years away, almost 3 times as far as fellow belt stars Alnitak and Mintaka. Though Rigel and Betelgeuse apparently shine brighter in planet Earth’s sky, that makes more distant Alnilam intrinsically (in absolute magnitude) the brightest of the familiar stars in Orion. In the Hipparcus catalog, errors in measured parallaxes for Orion’s stars can translate in to distance errors of a 100 light-years or so. [via NASA] https://ift.tt/32L2BFH

Arp 78: Peculiar Galaxy in Aries

(xxxedit and linkxxx) Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries, some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy. Also known as NGC 772, the island universe is over 100,000 light-years across and sports a single prominent outer spiral arm in this detailed cosmic portrait. Its brightest companion galaxy, compact NGC 770, is toward the upper right of the larger spiral. NGC 770’s fuzzy, elliptical appearance contrasts nicely with a spiky foreground Milky Way star in matching yellowish hues. Tracking along sweeping dust lanes and lined with young blue star clusters, Arp 78’s large spiral arm is likely due to gravitational tidal interactions. Faint streams of material seem to connect Arp 78 with its nearby companion galaxies. [via NASA] https://ift.tt/3mzKslW

Solar Cycle 25 Begins

The general trend of monthly sunspot data now confirms that the minimum of the approximately 11 year cycle of solar activity occurred in December 2019, marking the start of Solar Cycle 25. That quiet Sun, at minimum activity, appears on the right of this split hemispherical view. In contrast, the left side shows the active Sun at the recognized maximum of Solar Cycle 24, captured in April 2014. The extreme ultraviolet images from the orbiting Solar Dynamics Observatory highlight coronal loops and active regions in the light of highly ionized iron atoms. Driving the space weather around our fair planet, Solar Cycle 24 was a relatively calm one and predictions are that cycle 25 will be calm too. The cycle 25 activity maximum is expected in July 2025. Solar Cycle 1, the first solar cycle determined from early records of sunspot data, is considered to begin with a minimum in February 1755. [via NASA] https://ift.tt/35IRTRP

Gravel Ejected from Asteroid Bennu

Why does asteroid Bennu eject gravel into space? No one is sure. The discovery, occurring during several episodes by NASA’s visiting ORISIS-REx spacecraft, was unexpected. Leading ejection hypotheses include impacts by Sun-orbiting meteoroids, sudden thermal fractures of internal structures, and the sudden release of a water vapor jet. The featured two-image composite shows an ejection event that occurred in early 2019, with sun-reflecting ejecta seen on the right. Data and simulations show that large gravel typically falls right back to the rotating 500-meter asteroid, while smaller rocks skip around the surface, and the smallest rocks completely escape the low gravity of the Earth approaching, diamond-shaped asteroid. Jets and surface ejection events were thought to be predominantly the domain of comets, responsible for their tails, comas, and later meteor showers on Earth. Robotic OSIRIS-REx arrived at 101955 Bennu in late 2018, and is planned to touchdown to collect a surface sample in October 2020. If all goes well, this sample will then be returned to Earth for a detailed analysis during 2023. Bennu was chosen as the destination for OSIRIS-REx in part because its surface shows potential to reveal organic compounds from the early days of our Solar System, compounds that could have been the building blocks for life on Earth. [via NASA] https://ift.tt/2FoQKEz

Biomarker Phosphine Discovered in the Atmosphere of Venus

Could there be life floating in the atmosphere of Venus? Although Earth’s planetary neighbor has a surface considered too extreme for any known lifeform, Venus’ upper atmosphere may be sufficiently mild for tiny airborne microbes. This usually disfavored prospect took an unexpected upturn yesterday with the announcement of the discovery of Venusian phosphine. The chemical phosphine (PH3) is a considered a biomarker because it seems so hard to create from routine chemical processes thought to occur on or around a rocky world such as Venus — but it is known to be created by microbial life on Earth. The featured image of Venus and its thick clouds was taken in two bands of ultraviolet light by the Venus-orbing Akatsuki, a Japanese robotic satellite that has been orbiting the cloud-shrouded world since 2015. The phosphine finding, if confirmed, may set off renewed interest in searching for other indications of life floating high in the atmosphere of our Solar System’s second planet out from the Sun. [via NASA] https://ift.tt/3mmwKD3

Corn Moon Rising

A rising moon can be a dramatic sight. A rising Full Corn Moon was captured early this month in time-lapse with a telephoto lens from nearly 30 kilometers away — making Earth’s ascending half-degree companion appear unusually impressive. The image was captured from Portugal, although much of the foreground — including lights from the village of Puebla de Guzmán — is in Spain. A Full Corn Moon is the name attributed to a full moon at this time of year by cultures of some northern indigenous peoples of the Americas, as it coincides with the ripening of corn. Note that the Moon does not appear larger when it is nearer the horizon — its seemingly larger size there is only an illusion. The next full moon — occurring at the beginning of next month — will be known as the Full Harvest Moon as it occurs nearest in time to the northern autumnal equinox and the northern field harvests. [via NASA] https://ift.tt/3kcNbzU

M2 9: Wings of a Butterfly Nebula

Are stars better appreciated for their art after they die? Actually, stars usually create their most artistic displays as they die. In the case of low-mass stars like our Sun and M2-9 pictured here, the stars transform themselves from normal stars to white dwarfs by casting off their outer gaseous envelopes. The expended gas frequently forms an impressive display called a planetary nebula that fades gradually over thousands of years. M2-9, a butterfly planetary nebula 2100 light-years away shown in representative colors, has wings that tell a strange but incomplete tale. In the center, two stars orbit inside a gaseous disk 10 times the orbit of Pluto. The expelled envelope of the dying star breaks out from the disk creating the bipolar appearance. Much remains unknown about the physical processes that cause and shape planetary nebulae. [via NASA] https://ift.tt/3kaHqmi

The Reappearance of Mars

Mars reappears just beyond the Moon’s dark limb in this stack of sharp video frames captured on September 6. Of course to reappear it had to disappear in the first place. It did that over an hour earlier when the sunlit southern edge of the waning gibbous Moon passed in front of the Red Planet as seen from Maceio, Brazil. The lunar occultation came as the Moon was near apogee, about 400,000 kilometers away. Mars was almost 180 times more distant. It was the fourth lunar occultation of Mars visible from planet Earth in 2020. Visible from some southern latitudes, the fifth lunar occultation of Mars in 2020 will take place on October 3 when the Moon and Mars are both nearly opposite the Sun in planet Earth’s sky. [via NASA] https://ift.tt/2GKtkJP

Jupiter s Swimming Storm

A bright storm head with a long turbulent wake swims across Jupiter in these sharp telescopic images of the Solar System’s ruling gas giant. Captured on August 26, 28, and September 1 (left to right) the storm approximately doubles in length during that period. Stretching along the jetstream of the planet’s North Temperate Belt it travels eastward in successive frames, passing the Great Red Spot and whitish Oval BA, famous storms in Jupiter’s southern hemisphere. Galilean moons Callisto and Io are caught in the middle frame. In fact, telescopic skygazers following Jupiter in planet Earth’s night have reported dramatic fast moving storm outbreaks over the past few weeks in Jupiter’s North Temperate Belt. [via NASA] https://ift.tt/32bVZjo

Pleiades: The Seven Sisters Star Cluster

Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as large and clear as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city. With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The featured exposure covers a sky area several times the size of the full moon. Also known as the Seven Sisters and M45, the Pleiades lies about 400 light years away toward the constellation of the Bull (Taurus). A common legend with a modern twist is that one of the brighter stars faded since the cluster was named, leaving only six of the sister stars visible to the unaided eye. The actual number of Pleiades stars visible, however, may be more or less than seven, depending on the darkness of the surrounding sky and the clarity of the observer’s eyesight. [via NASA] https://ift.tt/3k0p2fP