Neptune's Cloud Cover is Linked to the Solar Cycle

This sequence of Hubble Space Telescope images chronicles the waxing and waning of the amount of cloud cover on Neptune. Credits: NASA, ESA, Erandi Chavez (UC Berkeley), Imke de Pater (UC Berkeley)

Whenever Neptune reaches its closest point in the sky to Earth, its portrait is taken by the Hubble Space Telescope and other ground-based observatories. Watching the planet from 1994 to 2020, astronomers have made puzzling discovery.

The clouds in Neptune’s atmosphere appear to be to be linked to the solar cycle and not the planet’s cycle of seasons. The global cloud cover seems to come and go in a cycle that apparently syncs up with the Sun’s 11-year cycle, as it shifts from solar maximum to solar minimum or vice versa. This is surprising since Neptune is so far from the Sun and receives about 0.1% of Earth’s sunlight.

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DART Impact Ejected 37 Giant Boulders from Asteroid Dimorphos’ Surface

This NASA/ESA Hubble Space Telescope image of the asteroid Dimorphos was taken on 19 December 2022, nearly four months after the asteroid was impacted by NASA’s DART (Double Asteroid Redirection Test) mission. Hubble’s sensitivity reveals a few dozen boulders knocked off the asteroid by the force of the collision. These are among the faintest objects Hubble has ever photographed inside the Solar System. Credit: NASA, ESA, D. Jewitt (UCLA).

When the DART (Double Asteroid Redirection Test) spacecraft intentionally slammed into asteroid moonlet Dimorphos on September 26, 2022, telescopes around the world and those in space watched as it happened, and continued to monitor the aftermath.

Of course, the Hubble Space Telescope was focused on the event. In looking at Hubble’s images and data from post-impact, astronomers discovered 37 boulders that were ejected due to the impact. These boulders range in size from 1 meter (3 feet) to 6.7 meters (22 feet).

However, these boulders were not debris created by the spacecraft’s impact. Instead, they were boulders that were already on the surface of Dimorphos, and the impact event “shook” the boulders loose. A team of astronomers, led by David Jewitt and Yoonyoung Kim say in their paper detailing the findings that these boulders are some of the faintest objects ever imaged in the Solar System, only visible because of Hubble’s keen sensitivity. The images here showing the boulders surrounding Dimorphos were taken on December 19, 2022.

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A Black Hole Switched On in the Blink of an Eye

This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. This thin disc of rotating material consists of the leftovers of a Sun-like star which was ripped apart by the tidal forces of the black hole. Shocks in the colliding debris as well as heat generated in accretion led to a burst of light, resembling a supernova explosion. Credit: ESO, ESA/Hubble, M. Kornmesser

In 2019, a team of astronomers led by Dr. Samantha Oates of the University of Birmingham discovered one of the most powerful transients ever seen – where astronomical objects change their brightness over a short period. Oates and her colleagues found this object, known as J221951-484240 (or J221951), using the Ultra-Violet and Optical Telescope (UVOT) on NASA’s Neil Gehrels Swift Observatory while searching for the source of a gravitational wave (GW) that was thought to be caused by two massive objects merging in our galaxy.

Multiple follow-up observations were made using the UVOT and Swift’s other instruments – the Burst Alert Telescope (BAT) and X-Ray Telescope (XRT), the Hubble Space Telescope, the South African Large Telescope (SALT), the Wide-field Infrared Survey Explorer (WISE), the ESO’s Very Large Telescope (VLT), the Australia Telescope Compact Array (ATCA), and more. The combined observations and spectra revealed that the source was a supermassive black hole (SMBH) in a distant galaxy that mysteriously “switched on,” becoming one of the most dramatic bursts of brightness ever seen with a black hole.

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Astronomers See the Same Supernova Four Times Thanks to a Gravitational Lens

A gravitational lens caused by a galaxy in the foreground leading to an "Einstein Cross." Credit: NASA/ESA/STScI
A gravitational lens caused by a galaxy in the foreground leading to an "Einstein Cross." Credit: NASA/ESA/STScI

Measuring cosmic distances is challenging, and astronomers rely on multiple methods and tools to do it – collectively referred to as the Cosmic Distance Ladder. One particularly crucial tool is Type Ia supernovae, which occur in binary systems where one star (a white dwarf) consumes matter from a companion (often a red giant) until it reaches the Chandrasekhar Limit and collapses under its own mass. As these stars blow off their outer layers in a massive explosion, they temporarily outshine everything in the background.

In a recent study, an international team of researchers led by Ariel Goobar of the Oskar Klein Centre at Stockholm University discovered an unusual Type Ia supernova, SN Zwicky (SN 2022qmx). In an unusual twist, the team observed an “Einstein Cross,” an unusual phenomenon predicted by Einstein’s Theory of General Relativity where the presence of a gravitational lens in the foreground amplifies light from a distant object. This was a major accomplishment for the team since it involved observing two very rare astronomical events that happened to coincide.

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Chandra and JWST Join Forces in a Stunning Series of Images

Credit: X-ray: Chandra: NASA/CXC/SAO, XMM: ESA/XMM-Newton; IR: JWST: NASA/ESA/CSA/STScI, Spitzer: NASA/JPL/CalTech; Optical: Hubble: NASA/ESA/STScI, ESO; Image Processing: L. Frattare, J. Major, N. Wolk, and K. Arcand

New images that combine data from NASA’s Chandra X-ray Observatory and the James Webb Space Telescope (JWST) JWST have just been released! The images feature four iconic astronomical objects, showcasing the capabilities of these observatories by combining light in the visible, infrared, and X-ray wavelengths. These include the NGC 346 star cluster located in the Small Magellanic Cloud (SMC), the NGC 1672 spiral galaxy, the Eagle Nebula (Messier 16, or M16), and the spiral galaxy Messier 74 (aka. the Phantom Galaxy).

These objects were made famous by the venerable Hubble Space Telescope, which took pictures of them between 1995 and 2005. Since it commenced operations, the JWST has conducted follow-up observations that provided a sharper view of these objects that captured additional features. Hubble and the JWST even teamed up to provide a multi-wavelength view of the Phantom Galaxy last year. By adding Chandra’s famed X-ray imaging capabilities to Webb’s sensitivity and infrared light, these latest images provide a new glimpse of these objects, revealing both faint and more energetic and powerful features.

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Where Are the Missing Black Holes? The Hubble May Have Helped Find One

This Hubble Space Telescope image shows the globular cluster Messier 4. It contains several hundre thousand stars, and its center might host an elusive intermediate-mass black hole. The black hole could have 800 solar masses. Image Credit: ESA/Hubble & NASA

Most black holes are stellar mass black holes. They’re created when a star several times more massive than our Sun reaches the end and collapses in on itself. There are also supermassive black holes (SMBH,) the behemoths at the center of galaxies that can boast billions of times more mass than the Sun.

But where are the intermediate-mass black holes?

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Gaze at a Nearby Actively Feeding Supermassive Black Hole

This Hubble image shows the central region of NGC 4395. The image uses data from Hubble's Wide Field Camera 3. Credits: NASA, ESA, S. Larsen (Radboud Universiteit Nijmegen) and E. Sabbi (STScI); Processing: Gladys Kober (NASA/Catholic University of America)

Astronomers recently shared a new image captured by the Hubble Space Telescope of the galaxy NGC 4395. This relatively diffuse and dim dwarf galaxy is located just 14 million light-years from Earth.

NGC 4395 has several oddities, and this new image zooms in on the galaxy’s central region to highlight just one of those quirks. NGC 4395 is different from other dwarf galaxies because it contains an actively feeding supermassive black hole at its center.

But this black hole is considered one of the lowest mass supermassive holes ever detected, an oxymoron if there ever was one.  

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Saturn’s Rings Warm Up its Atmosphere

Composite image of hydrogen emissions observed on Saturn gathered between 1980 and 2017 by Voyager 1, Cassini, and Hubble. A near-ultraviolet image taken by Hubble in 2017 being used to calibrate the almost 40 years of data. The amount of reflected ultraviolet (UV) sunlight is measured in brightness, with the rings reflecting the least amount UV sunlight. The dark spot at the pole is Saturn's spin axis. (Credit: NASA, ESA, Lotfi Ben-Jaffel (IAP & LPL))

Saturn’s rings are one of the most well-known features throughout astronomy. While much is known about them, they still make headlines from time to time. This includes a recent study involving an international team of researchers that could help paint a clearer picture of the interaction between the gas giant and the massive ring system that encircles it.

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Astronomers Think They've Found One of the Biggest Black Holes Ever Seen

Artist's impression of an ultramassive black hole (UBH). Credit: ESA/Hubble/DSS/Nick Risinger/N. Bartmann

In 1931, Indian-American physicist Subrahmanyan Chandrasekhar proposed a resolution to Einstein’s Theory of General Relativity that postulated the existence of black holes. By 1972, astronomers obtained the first conclusive evidence that these objects existed in our Universe. Observations of quasars and the center of the Milky Way also revealed that most massive galaxies have supermassive black holes (SMBHs) at their cores. Since then, the study of black holes has revealed that these objects vary in size and mass, ranging from micro black holes (MBHs) and intermediate black holes (IMBHs) to SMBHs.

Using astronomical simulations and a technique known as Gravitational Lensing, an international team of astrophysicists detected what could be the largest black hole ever observed. This ultramassive black hole (UMBH) has a mass roughly 30 billion times that of our Sun and is located near the center of the Abell 1201 galaxy cluster, roughly 2.7 billion light-years from Earth. This is the first time a black hole has been found using Gravitational Lensing, and it could enable studies that look farther into space to find black holes and deepen our understanding of their size and scale.

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It's Time For Your Annual Weather Update for the Outer Solar System

Jupiter, as seen by the Hubble Space Telescope in November 2022 and January 2023. Credits: NASA, ESA, STScI, Amy Simon (NASA-GSFC), and Michael H. Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI).

A couple times a year, the Hubble Space Telescope turns its powerful gaze on the giant planets in the outer Solar System, studying their cloudtops and weather systems. With the Outer Planet Atmospheres Legacy (OPAL) Program, Hubble provides us with these views and also delivers weather reports on what’s happening. Here’s an updated report and some new images of the stormy surfaces of Jupiter and Uranus.  

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