Our galaxy has about 200 Globular Clusters (GCs,) and most of them are in the galaxy’s halo. Astronomers think most GCs were taken from dwarf galaxies and merged with the Milky Way due to the galaxy’s powerful gravity. That explains why so many of them are on the outskirts of the galaxy. But they’re not all in the halo. Some are towards the Milky Way’s galactic bulge. What are globular clusters doing there?
Continue reading “The Hubble Imaged Some Globular Clusters in an Unusual Place: Near the Milky Way’s Centre”JWST Plucks One Single Star out of a Galaxy Seen 12.5 Billion Years Ago
After years of build-up and anticipation, the James Webb Space Telescope finally launched into orbit on December 25th, 2021 (what a Christmas present, huh?). Since then, the stunning images and data it has returned have proven beyond a doubt that it was the best Christmas present ever! After its first year of operations, the JWST has lived up to one of its primary objectives: to observe the first stars and galaxies that populated the Universe. The next-generation observatory has accomplished that by setting new distance records and revealing galaxies that existed less than 1 billion years after the Big Bang!
These studies are essential to charting the evolution of the cosmos and resolving issues with our cosmological models, like the Hubble Tension and the mysteries of Dark Matter and Dark Energy. Well, hang onto your hats because things have reached a new level of awesome! In a recent study, an international team of scientists isolated a well-magnified star candidate in a galaxy that appears as it was almost 12.5 billion years ago. The detection of a star that existed when the Universe was only ~1.2 billion years old showcases the abilities of the JWST and offers a preview of what’s to come!
Continue reading “JWST Plucks One Single Star out of a Galaxy Seen 12.5 Billion Years Ago”Neptune's Cloud Cover is Linked to the Solar Cycle
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.
Continue reading “Neptune's Cloud Cover is Linked to the Solar Cycle”DART Impact Ejected 37 Giant Boulders from Asteroid Dimorphos’ Surface
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.
Continue reading “DART Impact Ejected 37 Giant Boulders from Asteroid Dimorphos’ Surface”Gaze at a Nearby Actively Feeding Supermassive Black Hole
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.
Continue reading “Gaze at a Nearby Actively Feeding Supermassive Black Hole”It's Time For Your Annual Weather Update for the Outer Solar System
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.
Continue reading “It's Time For Your Annual Weather Update for the Outer Solar System”Humans Can Still Find Galaxies That Machine Learning Algorithms Miss
The age of big data is upon us, and there are scarcely any fields of scientific research that are not affected. Take astronomy, for example. Thanks to cutting-edge instruments, software, and data-sharing, observatories worldwide are accumulating hundreds of terabytes in a single day and between 100 to 200 Petabytes a year. Once next-generation telescopes become operational, astronomy will likely enter the “exabyte era,” where 1018 bytes (one quintillion) of data are obtained annually. To keep up with this volume, astronomers are turning to machine learning and AI to handle the job of analysis.
While AI plays a growing role in data analysis, there are some instances where citizen astronomers are proving more capable. While examining data collected by the Dark Energy Survey (DES), amateur astronomer Giuseppe Donatiello discovered three faint galaxies that a machine-learning algorithm had apparently missed. These galaxies, all satellites of the Sculptor Galaxy (NGC 253), are now named Donatello II, III, and IV, in his honor. In this day of data-driven research, it’s good to know that sometimes there’s no substitute for human eyeballs and intellect.
Continue reading “Humans Can Still Find Galaxies That Machine Learning Algorithms Miss”Beautiful New Hubble Photo Shows Hot, Young Variable Stars in the Orion Nebula
Here’s another striking image from the venerable Hubble Space Telescope. These billows of blue and red show a detailed look at a small portion of the famous Orion Nebula. But what really catches the eye are the brilliant stars with the cross-shaped diffraction spikes — a hallmark of Hubble images.
Continue reading “Beautiful New Hubble Photo Shows Hot, Young Variable Stars in the Orion Nebula”The JWST is the Shiny New Space Telescope, but the Dependable Hubble is Still Going Strong
The Venerable Hubble Space Telescope has cemented its place in history. Some call it the most successful science experiment ever. And while the James Webb Space Telescope might vie for that title, the Hubble does things that even the powerful JWST can’t do.
Exhibit A: this stunning image of NGC 6355.
Continue reading “The JWST is the Shiny New Space Telescope, but the Dependable Hubble is Still Going Strong”Wandering Stars Have Been Adrift Between Galaxies for Billions of Years
In the giant galaxy clusters in the Universe, which can consist of hundreds or thousands of galaxies, there are countless “rogue” stars wandering between them. These stars are not gravitationally bound to any individual galaxy but to the halo of galaxy clusters themselves and are only discernible by the diffuse light they emit – “Ghost Light” or “Intracluster light” (ICL). For astronomers, the explanation for how these stars became so scattered throughout their galaxy clusters has always been an unresolved question.
There are several theories, including the possibility that the stars were pulled from their galaxies, ejected in the course of galactic mergers, or were part of their cluster since its early formation billions of years ago. Using NASA’s Hubble Space Telescope, a team from Yonsei University, Seoul, and the University of California, Davis, conducted an infrared survey of distant galaxy clusters. Their observations suggest that these wandering stars have been adrift for billions of years and were not stripped from their respective galaxies.
Continue reading “Wandering Stars Have Been Adrift Between Galaxies for Billions of Years”