2024 April 28

Rings Around the Ring Nebula
Image Credit: Hubble, Large Binocular Telescope, Subaru Telescope; Composition & Copyright: Robert Gendler

The Ring Nebula (M57) is more complicated than it appears through a small telescope. The easily visible central ring is about one light-year across, but this remarkably deep exposure - a collaborative effort combining data from three different large telescopes - explores the looping filaments of glowing gas extending much farther from the nebula's central star. This composite image includes red light emitted by hydrogen as well as visible and infrared light. The Ring Nebula is an elongated planetary nebula, a type of nebula created when a Sun-like star evolves to throw off its outer atmosphere and become a white dwarf star. The Ring Nebula is about 2,500 light-years away toward the musical constellation Lyra.

🎆Your Sky Surprise: What picture did APOD feature on your birthday? 🎂 (post 1995)

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2024 May 1

IC 1795: The Fishhead Nebula
Image Credit & Copyright: Roberto Colombari & Mauro Narduzzi

To some, this nebula looks like the head of a fish. However, this colorful cosmic portrait really features glowing gas and obscuring dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia. The nebula's colors were created by adopting the Hubble color palette for mapping narrowband emissions from oxygen, hydrogen, and sulfur atoms to blue, green and red colors, and further blending the data with images of the region recorded through broadband filters. Not far on the sky from the famous Double Star Cluster in Perseus, IC 1795 is itself located next to IC 1805, the Heart Nebula, as part of a complex of star forming regions that lie at the edge of a large molecular cloud. Located just over 6,000 light-years away, the larger star forming complex sprawls along the Perseus spiral arm of our Milky Way Galaxy. At that distance, IC 1795 would span about 70 light-years across.

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2024 May 2

M100: A Grand Design Spiral Galaxy
Image Credit & Copyright: Drew Evans

Majestic on a truly cosmic scale, M100 is appropriately known as a grand design spiral galaxy. The large galaxy of over 100 billion stars has well-defined spiral arms, similar to our own Milky Way. One of the brightest members of the Virgo Cluster of galaxies, M100, also known as NGC 4321 is 56 million light-years distant toward the well-groomed constellation Coma Berenices. In this telescopic image, the face-on grand design spiral shares a nearly 1 degree wide field-of-view with slightly less conspicuous edge-on spiral NGC 4312 (at upper right). The 21 hour long equivalent exposure from a dark sky site near Flagstaff, Arizona, planet Earth, reveals M100's bright blue star clusters and intricate winding dust lanes which are hallmarks of this class of galaxies. Measurements of variable stars in M100 have played an important role in determining the size and age of the Universe.

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2024 May 3

Temperatures on Exoplanet WASP-43b
Illustration Credit: NASA, ESA, CSA, Ralf Crawford (STScI)
Science: Taylor Bell (BAERI), Joanna Barstow (The Open University), Michael Roman (University of Leicester)

A mere 280 light-years from Earth, tidally locked, Jupiter-sized exoplanet WASP-43b orbits its parent star once every 0.8 Earth days. That puts it about 2 million kilometers (less than 1/25th the orbital distance of Mercury) from a small, cool sun. Still, on a dayside always facing its parent star, temperatures approach a torrid 2,500 degrees F as measured at infrared wavelengths by the MIRI instrument on board the James Webb Space Telescope. In this illustration of the hot exoplanet's orbit, Webb measurements also show nightside temperatures remain above 1,000 degrees F. That suggests that strong equatorial winds circulate the dayside atmospheric gases to the nightside before they can completely cool off. Exoplanet WASP-43b is now formally known as Astrolábos, and its K-type parent star has been christened Gnomon. Webb's infrared spectra indicate water vapor is present on the nightside as well as the dayside of the planet, providing information about cloud cover on Astrolábos.

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2024 May 4

3 ATs
Image Credit & Copyright: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN)

Despite their resemblance to R2D2, these three are not the droids you're looking for. Instead, the enclosures house 1.8 meter Auxiliary Telescopes (ATs) at Paranal Observatory in the Atacama Desert region of Chile. The ATs are designed to be used for interferometry, a technique for achieving extremely high resolution observations, in concert with the observatory's 8 meter Very Large Telescope units. A total of four ATs are operational, each fitted with a transporter that moves the telescope along a track allowing different arrays with the large unit telescopes. To work as an interferometer, the light from each telescope is brought to a common focal point by a system of mirrors in underground tunnels. Above these three ATs, the Large and Small Magellanic Clouds are the far, far away satellite galaxies of our own Milky Way. In the clear and otherwise dark southern skies, planet Earth's greenish atmospheric airglow stretches faintly along the horizon.

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2024 May 5

A Black Hole Disrupts a Passing Star
Illustration Credit: NASA, JPL-Caltech

What happens to a star that goes near a black hole? If the star directly impacts a massive black hole, then the star falls in completely -- and everything vanishes. More likely, though, the star goes close enough to have the black hole's gravity pull away its outer layers, or disrupt, the star. Then, most of the star's gas does not fall into the black hole. These stellar tidal disruption events can be as bright as a supernova, and an increasing amount of them are being discovered by automated sky surveys. In the featured artist's illustration, a star has just passed a massive black hole and sheds gas that continues to orbit. The inner edge of a disk of gas and dust surrounding the black hole is heated by the disruption event and may glow long after the star is gone.

🌌Hole New Worlds: It's Black Hole Week at NASA!

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2024 May 6

A Total Solar Eclipse from Sliver to Ring
Video Credit & Copyright: Reinhold Wittich; Music: Sunrise from Also sprach Zarathusra (R. Strauss) by Sascha Ende

This is how the Sun disappeared from the daytime sky last month. The featured time-lapse video was created from stills taken from Mountain View, Arkansas, USA on 2024 April 8. First, a small sliver of a normally spotted Sun went strangely dark. Within a few minutes, much of the background Sun was hidden behind the advancing foreground Moon. Within an hour, the only rays from the Sun passing the Moon appeared like a diamond ring. During totality, most of the surrounding sky went dark, making the bright pink prominences around the Sun's edge stand out, and making the amazing corona appear to spread into the surrounding sky. The central view of the corona shows an accumulation of frames taken during complete totality. As the video ends, just a few minutes later, another diamond ring appeared -- this time on the other side of the Moon. Within the next hour, the sky returned to normal.

🚀Celebrate the Voids: It's Black Hole Week at NASA!

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2024 May 7

Black Hole Accreting with Jet
Illustration Credit: NASA, Swift, Aurore Simonnet (Sonoma State U.)

What happens when a black hole devours a star? Many details remain unknown, but observations are providing new clues. In 2014, a powerful explosion was recorded by the ground-based robotic telescopes of the All Sky Automated Survey for SuperNovae (Project ASAS-SN), with followed-up observations by instruments including NASA's Earth-orbiting Swift satellite. Computer modeling of these emissions fit a star being ripped apart by a distant supermassive black hole. The results of such a collision are portrayed in the featured artistic illustration. The black hole itself is a depicted as a tiny black dot in the center. As matter falls toward the hole, it collides with other matter and heats up. Surrounding the black hole is an accretion disk of hot matter that used to be the star, with a jet emanating from the black hole's spin axis.

🚀Fall towards eternity: It's Black Hole Week at NASA!

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2024 May 8

Visualization: A Black Hole Accretion Disk
Visualization Credit: NASA’s Goddard Space Flight Center, Jeremy Schnittman

What would it look like to circle a black hole? If the black hole was surrounded by a swirling disk of glowing and accreting gas, then the great gravity of the black hole would deflect light emitted by the disk to make it look very unusual. The featured animated video gives a visualization. The video starts with you, the observer, looking toward the black hole from just above the plane of the accretion disk. Surrounding the central black hole is a thin circular image of the orbiting disk that marks the position of the photon sphere -- inside of which lies the black hole's event horizon. Toward the left, parts of the large main image of the disk appear brighter as they move toward you. As the video continues, you loop over the black hole, soon looking down from the top, then passing through the disk plane on the far side, then returning to your original vantage point. The accretion disk does some interesting image inversions -- but never appears flat. Visualizations such as this are particularly relevant today as black holes are being imaged in unprecedented detail by the Event Horizon Telescope.

🚀Singularity Impressive: It's Black Hole Week at NASA!

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2024 May 9

The Galaxy, the Jet, and a Famous Black Hole
Image Credit: NASA, JPL-Caltech, Event Horizon Telescope Collaboration

Bright elliptical galaxy Messier 87 (M87) is home to the supermassive black hole captured in 2017 by planet Earth's Event Horizon Telescope in the first ever image of a black hole. Giant of the Virgo galaxy cluster about 55 million light-years away, M87 is the large galaxy rendered in blue hues in this infrared image from the Spitzer Space telescope. Though M87 appears mostly featureless and cloud-like, the Spitzer image does record details of relativistic jets blasting from the galaxy's central region. Shown in the inset at top right, the jets themselves span thousands of light-years. The brighter jet seen on the right is approaching and close to our line of sight. Opposite, the shock created by the otherwise unseen receding jet lights up a fainter arc of material. Inset at bottom right, the historic black hole image is shown in context, at the center of giant galaxy and relativistic jets. Completely unresolved in the Spitzer image, the supermassive black hole surrounded by infalling material is the source of enormous energy driving the relativistic jets from the center of active galaxy M87. The Event Horizon Telescope image of M87 has been enhanced to reveal a sharper view of the famous supermassive black hole.

🌌It's inescapable: Black Hole Week at NASA!

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2024 May 10

Simulation: Two Black Holes Merge
Simulation Credit: Simulating eXtreme Spacetimes Project

Relax and watch two black holes merge. Inspired by the first direct detection of gravitational waves in 2015, this simulation plays in slow motion but would take about one third of a second if run in real time. Set on a cosmic stage, the black holes are posed in front of stars, gas, and dust. Their extreme gravity lenses the light from behind them into Einstein rings as they spiral closer and finally merge into one. The otherwise invisible gravitational waves generated as the massive objects rapidly coalesce cause the visible image to ripple and slosh both inside and outside the Einstein rings even after the black holes have merged. Dubbed GW150914, the gravitational waves detected by LIGO are consistent with the merger of 36 and 31 solar mass black holes at a distance of 1.3 billion light-years. The final, single black hole has 63 times the mass of the Sun, with the remaining 3 solar masses converted into energy radiated in gravitational waves.

🚀Today's Event Horizon: It's Black Hole Week at NASA!

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2024 May 11

AR 3664: Giant Sunspot Group
Image Credit & Copyright: Franco Fantasia & Guiseppe Conzo (Gruppo Astrofili Palidoro)

Right now, one of the largest sunspot groups in recent history is crossing the Sun. Active Region 3664 is not only big -- it's violent, throwing off clouds of particles into the Solar System. Some of these CMEs are already impacting the Earth, and others might follow. At the extreme, these solar storms could cause some Earth-orbiting satellites to malfunction, the Earth's atmosphere to slightly distort, and electrical power grids to surge. When impacting Earth's upper atmosphere, these particles can produce beautiful auroras, with some auroras already being reported unusually far south. Pictured here, AR3664 and its dark sunspots were captured yesterday in visible light from Rome, Italy. The AR3664 sunspot group is so large that it is visible just with glasses designed to view last month's total solar eclipse. This weekend, skygazing enthusiasts will be keenly watching the night skies all over the globe for bright and unusual auroras.

🖼Gallery: Active Region 3664 on the Sun and Associated Aurora

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2024 May 12

Red Aurora over Poland
Image Credit & Copyright: Mariusz Durlej

Northern lights don't usually reach this far south. Magnetic chaos in the Sun's huge Active Region 3664, however, produced a surface explosion that sent a burst of electrons, protons, and more massive, charged nuclei into the Solar System. A few days later, that coronal mass ejection (CME) impacted the Earth and triggered auroras that are being reported unusually far from our planet's north and south poles. The free sky show might not be over -- the sunspot rich AR3664 has ejected even more CMEs that might also impact the Earth tonight or tomorrow. That active region is now near the Sun's edge, though, and will soon be rotating away from the Earth. Pictured, a red and rayed aurora was captured in a single 6-second exposure from Racibórz, Poland early last night. The photographer's friend, seeing an aurora for the first time, is visible in the distance also taking images of the beautifully colorful nighttime sky.

🖼Gallery: Global Aurora from Solar Active Region 6443

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2024 May 13

AR 3664 on a Setting Sun
Image Credit & Copyright: Marco Meniero

It was larger than the Earth. It was so big you could actually see it on the Sun's surface without magnification. It contained powerful and tangled magnetic fields as well as numerous dark sunspots. Labelled AR 3664, it developed into one of the most energetic areas seen on the Sun in recent years, unleashing a series of explosions that led to a surge of energetic particles striking the Earth, which created beautiful auroras. And might continue. Although active regions on the Sun like AR 3664 can be quite dangerous, this region's Coronal Mass Ejections have not done, as yet, much damage to Earth-orbiting satellites or Earth-surface electrical grids. Pictured, the enormous active region was captured on the setting Sun a few days ago from Civitavecchia, Rome, Italy. The composite image includes a very short exposure taken of just the Sun's surface, but mimics what was actually visible. Finally, AR 3664 is now rotating away from the Earth, although the region may survive long enough to come around again.

🖼Gallery: Earth Aurora from Solar Active Region 6443

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