Hubble Has Accidentally Discovered Over a Thousand Asteroids

Illustration of Asteroid (Artist’s Impression). Credit: N. Bartmann (ESA/Webb), ESO/M. Kornmesser and S. Brunier, N. Risinger

The venerable Hubble Space Telescope is like a gift that keeps on giving. Not only is it still making astronomical discoveries after more than thirty years in operation. It is also making discoveries by accident! Thanks to an international team of citizen scientists, with the help of astronomers from the European Space Agency (ESA) and some machine learning algorithms, a new sample of over one thousand asteroids has been identified in Hubble‘s archival data. The methods used represent a new approach for finding objects in decades-old data that could be applied to other datasets as well.

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If Europa has Geysers, They’re Very Faint

Jupiter's second Galilean moon, Europa. Its smooth surface has fewer craters than other moons, but they help us understand its icy shell. (Credit: NASA/JPL/Galileo spacecraft)
The Hubble spotted evidence of geysers coming from Jupiter's moon Europa, but nobody's been able to find them again. (Credit: NASA/JPL/Galileo spacecraft)

In 2013, the Hubble Space Telescope spotted water vapour on Jupiter’s moon Europa. The vapour was evidence of plumes similar to the ones on Saturn’s moon Enceladus. That, and other compelling evidence, showed that the moon has an ocean. That led to speculation that the ocean could harbour life.

But the ocean is obscured under a thick, global layer of ice, making the plumes our only way of examining the ocean. The plumes are so difficult to detect they haven’t been confirmed.

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It’s Time for Saturn’s “Spokes” to Return

This NASA Hubble Space Telescope photo of Saturn reveals the planet's cloud bands and a phenomenon called ring spokes. NASA, ESA, STScI, Amy Simon (NASA-GSFC)

Astronomers have been observing Saturn with the Hubble Space Telescope and several other spacecraft for decades and have noticed something unusual. During seasonal changes, transient spoke-like features appear in the rings. These dark, ghostly blobs orbit around the planet 2-3 times, and then disappear.

As Saturn is approaching its equinox, this is prime spoke activity time. Once again, Hubble has been called to gaze at Saturn, tracking the behavior of the spokes and hopefully giving astronomers more clues as to why they occur.

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Compare Images of a Galaxy Seen by Both Hubble and JWST

NGC 5068 is a barred spiral galaxy about 20 million light-years away. The Hubble captured this image of NGC 5068 in ultraviolet, visible, and near-infrared light. Image Credits: NASA, ESA, R. Chandar (University of Toledo), and J. Lee (Space Telescope Science Institute); Processing: Gladys Kober (NASA/Catholic University of America)

The James Webb Space Telescope is widely considered to be better than the Hubble Space Telescope. But the JWST doesn’t replace its elder sibling; it’s the Hubble’s successor. The Hubble is nowhere near ready to retire. It’s still a powerful science instrument with lots to contribute. Comparing images of the same object, NGC 5068, from both telescopes illustrates each one’s value and how they can work together.

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M87's Jet is Triggering Novae

The jet emerging from the galactic core of M87. NASA/STScI/AURA.

Everyone loves a good mystery, and astronomers have just uncovered a new one in a nearby supermassive galaxy called M87. Like most galaxies, M87 regularly plays host to a smattering of stellar explosions called novae, each the result of a star stealing material from a neighbour. M87 also features a massive jet of plasma blasting out into deep space from the galactic core. These phenomena: the jet and the novae, are unrelated astronomical occurrences, or so scientists believed. But astronomers recently discovered that the novae in M87 seem to be uncharacteristically aligned along the jet, instead of scattered randomly throughout the galaxy. Is the jet somehow triggering nova explosions?

It might be, but the mystery is: how?

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A Collection of New Images Reveal X-Rays Across the Universe

NASA/CXC/SAO, JPL-Caltech, MSFC, STScI, ESA/CSA, SDSS, ESO.

One of the miracles of modern astronomy is the ability to ‘see’ wavelengths of light that human eyes can’t. Last week, astronomers put that superpower to good use and released five new images showcasing the universe in every wavelength from X-ray to infrared.

Combining data from both Earth- and ground-based telescopes, the five images reveal a diverse set of astronomical phenomena, including the galactic centre, the death throes of stars, and distant galaxies traversing the cosmos.

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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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Hubble Sees Two Quasars Side by Side in the Early Universe

When it comes to the brightest, most powerful objects in the Universe, not much can beat a Quasar. A Gamma Ray Burst from a supernova might be more energetic, but doesn’t last very long. Quasars, by comparison, can churn out 1000 times the radiation of the Milky Way, and keep doing it for hundreds of millions of years.

They get all this energy from the supermassive black holes that live at the center of galaxies. As material falls towards the black hole, an accretion disk forms around it: a swirling cloud of energetic material which heats up through friction and releases electromagnetic radiation. The resulting Quasar can be so bright it drowns out the light from the rest of its galaxy from our perspective.

On April 5th, researchers announced the discovery of a rare double quasar in the early Universe. The two quasars are gravitationally bound, spiraling in towards each other. Their host galaxies are in the process of merging, and the supermassive black holes generating the quasars will also eventually collide and merge.

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A new Hubble Image Reveals a Shredded Star in a Nearby Galaxy

The latest composite image of supernova remnant DEM L 190, released in November 2022. Credit: ESA/Hubble & NASA, S. Kulkarni, Y. Chu

The Hubble Space Telescope, to which we owe our current estimates for the age of the universe and the first detection of organic matter on an exoplanet, is very much doing science and still alive. It’s latest masterpiece remixes an old hit – apparently a growing trend in space science as well as space music.

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By Looking Back Through Hubble Data, Astronomers Have Identified six Massive Stars Before They Exploded as Core-Collapse Supernovae

Hubble Space Telescope
NASA's Hubble Space Telescope flies with Earth in the background after a 2002 servicing mission. (NASA Photo)

The venerable Hubble Space Telescope has given us so much during the history of its service (32 years, 7 months, 6 days, and counting!) Even after all these years, the versatile and sophisticated observatory is still pulling its weight alongside more recent addition, like the James Webb Space Telescope (JWST) and other members of NASA’s Great Observatories family. In addition to how it is still conducting observation campaigns, astronomers and astrophysicists are combing through the volumes of data Hubble accumulated over the years to find even more hidden gems.

A team led by Caltech’s recently made some very interesting finds in the Hubble archives, where they observed the sites of six supernovae to learn more about their progenitor stars. Their observations were part of the Hubble Space Telescope Snapshot program, where astronomers use HST images to chart the life cycle and evolution of stars, galaxies, and other celestial objects. From this, they were able to place constraints on the size, mass, and other key characteristics of the progenitor stars and what they experienced before experiencing core collapse.

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