Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 15

Explanation: Looping through the Jovian system in the late 1990s, the Galileo spacecraft recorded stunning views of Europa and uncovered evidence that the moon's icy surface likely hides a deep, global ocean. Galileo's Europa image data has been remastered here, with improved calibrations to produce a color image approximating what the human eye might see. Europa's long curving fractures hint at the subsurface liquid water. The tidal flexing the large moon experiences in its elliptical orbit around Jupiter supplies the energy to keep the ocean liquid. But more tantalizing is the possibility that even in the absence of sunlight that process could also supply the energy to support life, making Europa one of the best places to look for life beyond Earth. What kind of life could thrive in a deep, dark, subsurface ocean? Consider planet Earth's own extreme shrimp.

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 12

Explanation: What does Comet Leonard look like up close? Although we can't go there, imaging the comet's coma and inner tails through a small telescope gives us a good idea. As the name implies, the ion tail is made of ionized gas -- gas energized by ultraviolet light from the Sun and pushed outward by the solar wind. The solar wind is quite structured and sculpted by the Sun's complex and ever changing magnetic field. The effect of the variable solar wind combined with different gas jets venting from the comet's nucleus accounts for the tail's complex structure. Following the wind, structure in Comet Leonard's tail can be seen to move outward from the Sun even alter its wavy appearance over time. The blue color of the ion tail is dominated by recombining carbon monoxide molecules, while the green color of the coma surrounding the head of the comet is created mostly by a slight amount of recombining diatomic carbon molecules. Diatomic carbon is destroyed by sunlight in about 50 hours -- which is why its green glow does not make it far into the ion tail. The featured image was taken on January 2 from Siding Spring Observatory in Australia. Comet Leonard, presently best viewed from Earth's Southern Hemisphere, has rounded the Sun and is now headed out of the Solar System.

You're THE KING!! 👑

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 December 23

Explanation: Are you still looking for that perfect holiday gift for an astronomer? If your night sky is dark and horizon clear enough, the Solar System may have done your shopping for you. Send them outside after sunset to see three planets and a comet. In this snapshot of the December solstice evening sky from the village of Kirazli, Turkey the brightest celestial beacon is Venus, close to the southwestern horizon at the right. Look left and up to find Saturn shining between clouds. Follow that line farther left and up to bright Jupiter, the Solar System's ruling gas giant. This year's surprise visitor to the inner Solar System, Comet Leonard (C/2021 A1), is near the horizon too. The comet is fainter but forms a nearly equilateral triangle with planets Venus and Saturn in this view. After a dramatic brightening in recent days the comet is just visible to the unaided eye, though a nice pair of binoculars is always a good idea.

Now to hold our breath for ~1 month 😂

YEEEEEEEEEHAAAWWWW!!

🤘😎🤘 !!

Go judge!!! 🙌

When life gives Dr. Sekula lemons... 😎

They know mobile OSes suck, so they needed to continue the trend 😎

Bus Ride Buddy 公車旅伴

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 March 31

Explanation: To play on Carl Sagan’s famous words "If you wish to make black hole jets, you must first create magnetic fields." The featured image represents the detected intrinsic spin direction (polarization) of radio waves. The polarizationi is produced by the powerful magnetic field surrounding the supermassive black hole at the center of elliptical galaxy M87. The radio waves were detected by the Event Horizon Telescope (EHT), which combines data from radio telescopes distributed worldwide. The polarization structure, mapped using computer generated flow lines, is overlaid on EHT’s famous black hole image, first published in 2019. The full 3-D magnetic field is complex. Preliminary analyses indicate that parts of the field circle around the black hole along with the accreting matter, as expected. However, another component seemingly veers vertically away from the black hole. This component could explain how matter resists falling in and is instead launched into M87’s jet.

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 March 21

Explanation: No one knew that 2,000 years ago, the technology existed to build such a device. The Antikythera mechanism, pictured, is now widely regarded as the first computer. Found at the bottom of the sea aboard a decaying Greek ship, its complexity prompted decades of study, and even today some of its functions likely remain unknown. X-ray images of the device, however, have confirmed that a main function of its numerous clock-like wheels and gears is to create a portable, hand-cranked, Earth-centered, orrery of the sky, predicting future star and planet locations as well as lunar and solar eclipses. The corroded core of the Antikythera mechanism's largest gear is featured, spanning about 13 centimeters, while the entire mechanism was 33 centimeters high, making it similar in size to a large book. Recently, modern computer modeling of missing components is allowing for the creation of a more complete replica of this surprising ancient machine.

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 March 8

Explanation: What created the unusual red tail in Comet NEOWISE? Sodium. A spectacular sight back in the summer of 2020, Comet NEOWISE, at times, displayed something more than just a surprisingly striated white dust tail and a pleasingly patchy blue ion tail. Some color sensitive images showed an unusual red tail, and analysis showed much of this third tail's color was emitted by sodium. Gas rich in sodium atoms might have been liberated from Comet NEOWISE's warming nucleus in early July by bright sunlight, electrically charged by ultraviolet sunlight, and then pushed out by the solar wind. The featured image was captured in mid-July from Brittany, France and shows the real colors. Sodium comet tails have been seen before but are rare -- this one disappeared by late July. Comet C/2020 F3 (NEOWISE) has since faded, lost all of its bright tails, and now approaches the orbit of Jupiter as it heads back to the outer Solar System, to return only in about 7,000 years.

"Searching for Higgs boson twins"

Higgs-boson pairs could help scientists understand the stability of our universe. The trick is finding them.

https://www.symmetrymagazine.org/article/searching-for-higgs-boson-twins?utm_source=main_feed_click&utm_medium=rss&utm_campaign=main_feed&utm_content=click

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 February 25

Explanation: On a mission to explore the inner heliosphere and solar corona, on July 11, 2020 the Wide-field Imager on board NASA's Parker Solar Probe captured this stunning view of the nightside of Venus at distance of about 12,400 kilometers (7,693 miles). The spacecraft was making the third of seven gravity-assist flybys of the inner planet. The gravity-asssist flybys are designed to use the approach to Venus to help the probe alter its orbit to ultimately come within 6 million kilometers (4 million miles) of the solar surface in late 2025. A surprising image, the side-looking camera seems to peer through the clouds to show a dark feature near the center known as Aphrodite Terra, the largest highland region on the Venusian surface. The bright rim at the edge of the planet is nightglow likely emitted by excited oxygen atoms recombining into molecules in the upper reaches of the atmosphere. Bright streaks and blemishes throughout the image are likely due to energetic charged particles, and dust near the camera reflecting sunlight. Skygazers from planet Earth probably recognize the familiar stars of Orion's belt and sword at lower right.