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This Week's Sky at a Glance, July 24 – August 2
The waxing gibbous Moon passes Antares. Turn the Summer Triangle into the Summer Diamond. And as you snuggle into bed, would Vega land on your roof if it dropped out of the sky?
The post This Week's Sky at a Glance, July 24 – August 2 appeared first on Sky & Telescope.
New Jersey Meteorite Offers Early Solar System Clues
When a meteorite tore through a New Jersey home, the homeowner quickly preserved the fragments. Now, they're giving scientists a look at Earth's early history.
The post New Jersey Meteorite Offers Early Solar System Clues appeared first on Sky & Telescope.
How a 99-year-old mathematician unraveled a century-old braid mystery
Joan Birman popularized the Burau representation problem decades ago. Now she and two colleagues have a proof that reveals brand new insights into the geometry of braids
Hubble Spies One-Sided Spiral
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3 min read
Hubble Spies One-Sided Spiral This NASA/ESA Hubble Space Telescope image features the spiral galaxy NGC 4654, located 72 million light-years away in the constellation Virgo (the Maiden). NASA, ESA/Hubble, D. Thilker, J. Lee, and the PHANGS-HST Team
The subject of this NASA/ESA Hubble Space Telescope image is a spiral galaxy struggling against titanic forces that appear on galactic scales in space. This is NGC 4654, an intermediate spiral galaxy in the constellation Virgo (the Maiden). It is classified as an “intermediate” because its overall shape lies between spiral galaxies that have a bar across their centers and those that don’t. NGC 4654 has a weak bar structure at its center and is located 72 million light-years from Earth in the Virgo Cluster, a particularly massive and populous galaxy cluster.
NGC 4654 is particularly asymmetric, with a rounded and clearly-defined edge on one side and a long tail of gas stretching out from the opposite side — outside the field of view captured in this image. This gaseous tail is the result of ram pressure stripping, a force that galaxies can experience as they plow through space. NGC 4654 moves with such high velocity that it sweeps up and rams through the hot, rarefied gas filling the space between the Virgo Cluster’s galaxies. This intracluster medium in turn exerts a “ram pressure” on the galaxy, compressing the galaxy’s leading edge and dragging its gas behind the galaxy, creating the elongated tail.
It’s not just the galaxy’s gas that is unevenly distributed: its stars are too, and this is more unusual for a spiral galaxy. While the spiral arm on its leading edge is rich with stars and gas, the opposite arm noticeably lacks stars, influencing the galaxy’s lopsided spiral shape. Astronomers think that ram pressure alone is unlikely to cause this effect. Rather, NGC 4654 was also subjected to the gravitational force of fellow Virgo Cluster galaxy NGC 4639. While the two galaxies are far apart now, it’s thought that a fly-by interaction between them around 500 million years ago ripped away NGC 4654’s gas along one side, limiting star formation there and creating the asymmetry in its shape.
Many galaxies that undergo ram pressure stripping suffer reduced star formation rates as the cold gas that collapses to form their stars is pulled away and lost. NGC 4654, however, is still forming nearly two Suns’ worth of stars every year, a rate comparable to other galaxies of similar size. The active star formation is visible in the latest Hubble data included in this image. The data picks up on a wavelength of red light emitted by the clouds of energized gas where newborn stars lurk. The bright pink bubbles that appear across NGC 4654 — from its forward spiral arm, to around its weak bar, and out to the edge of its disk — are areas where these newborn stars shine.
The data used in this image came from two observing programs (#15654, #17502) that aim to link the gas in galaxies with star formation. By observing many prominent galaxies in the vicinity of our own, researchers hope to better understand how gas moves in galaxies, where and when it collapses to form stars and star clusters, and what effect those new stars have on the gas around them.
Text Credit: ESA/Hubble
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubbleMedia Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble’s Galaxies
Explore an assortment of galaxies with Hubble.
Hubble Science Highlights
Hubble’s most notable scientific discoveries reflect the broad range of research and the breakthroughs it has achieved.
Hubble Images
Explore Hubble’s iconic images of the universe, and view photos of mission operations and astronauts servicing Hubble in space.
Hubble Spies One-Sided Spiral
- Hubble Home
- Overview
- Impact & Benefits
- Science
- Observatory
- Team
- Multimedia
- News
- More
3 min read
Hubble Spies One-Sided Spiral This NASA/ESA Hubble Space Telescope image features the spiral galaxy NGC 4654, located 72 million light-years away in the constellation Virgo (the Maiden). NASA, ESA/Hubble, D. Thilker, J. Lee, and the PHANGS-HST TeamThe subject of this NASA/ESA Hubble Space Telescope image is a spiral galaxy struggling against titanic forces that appear on galactic scales in space. This is NGC 4654, an intermediate spiral galaxy in the constellation Virgo (the Maiden). It is classified as an “intermediate” because its overall shape lies between spiral galaxies that have a bar across their centers and those that don’t. NGC 4654 has a weak bar structure at its center and is located 72 million light-years from Earth in the Virgo Cluster, a particularly massive and populous galaxy cluster.
NGC 4654 is particularly asymmetric, with a rounded and clearly-defined edge on one side and a long tail of gas stretching out from the opposite side — outside the field of view captured in this image. This gaseous tail is the result of ram pressure stripping, a force that galaxies can experience as they plow through space. NGC 4654 moves with such high velocity that it sweeps up and rams through the hot, rarefied gas filling the space between the Virgo Cluster’s galaxies. This intracluster medium in turn exerts a “ram pressure” on the galaxy, compressing the galaxy’s leading edge and dragging its gas behind the galaxy, creating the elongated tail.
It’s not just the galaxy’s gas that is unevenly distributed: its stars are too, and this is more unusual for a spiral galaxy. While the spiral arm on its leading edge is rich with stars and gas, the opposite arm noticeably lacks stars, influencing the galaxy’s lopsided spiral shape. Astronomers think that ram pressure alone is unlikely to cause this effect. Rather, NGC 4654 was also subjected to the gravitational force of fellow Virgo Cluster galaxy NGC 4639. While the two galaxies are far apart now, it’s thought that a fly-by interaction between them around 500 million years ago ripped away NGC 4654’s gas along one side, limiting star formation there and creating the asymmetry in its shape.
Many galaxies that undergo ram pressure stripping suffer reduced star formation rates as the cold gas that collapses to form their stars is pulled away and lost. NGC 4654, however, is still forming nearly two Suns’ worth of stars every year, a rate comparable to other galaxies of similar size. The active star formation is visible in the latest Hubble data included in this image. The data picks up on a wavelength of red light emitted by the clouds of energized gas where newborn stars lurk. The bright pink bubbles that appear across NGC 4654 — from its forward spiral arm, to around its weak bar, and out to the edge of its disk — are areas where these newborn stars shine.
The data used in this image came from two observing programs (#15654, #17502) that aim to link the gas in galaxies with star formation. By observing many prominent galaxies in the vicinity of our own, researchers hope to better understand how gas moves in galaxies, where and when it collapses to form stars and star clusters, and what effect those new stars have on the gas around them.
Text Credit: ESA/Hubble
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubbleMedia Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble’s Galaxies
Explore an assortment of galaxies with Hubble.
Hubble Science Highlights
Hubble’s most notable scientific discoveries reflect the broad range of research and the breakthroughs it has achieved.
Hubble Images
Explore Hubble’s iconic images of the universe, and view photos of mission operations and astronauts servicing Hubble in space.
Is it possible to regain a sense of smell? These scientists are working on it
Smell is one of the most complex and least understood senses
The Rubin Observatory’s greatest legacy will be this ‘movie’ of the sky
Using the new Vera C. Rubin Observatory, astronomers are beginning the largest and deepest survey of the sky. What will they see?
Why total solar eclipses are so special
More than 2500 years ago, a total solar eclipse is said to have ended a war between the Lydians and the Medes. Today, we understand the science behind eclipses, but witnessing one is still one of the most awe-inspiring experiences on Earth.
In this video, discover how solar and lunar eclipses happen, why totality is so rare, and what makes a total solar eclipse so extraordinary. From ancient legends to modern ESA missions studying the Sun's corona, discover the science behind one of nature's greatest spectacles.
Discover more about the three European eclipses of 2026–2028 here.
Sunlight benefits and risks: what science says about healthy sun exposure
Could sunlight actually improve your health? New research suggests we may need to rethink total sun avoidance
Earth from Space: Agricultural patchwork
Two new Galileo satellites enter service
Two new satellites have now officially joined Europe’s Galileo satellite navigation constellation, strengthening its capabilities, resilience and autonomy. Four Galileo First Generation satellites remain to be launched, with the next pair planned for the end of the year.
How lost shipping containers helped map the world’s ocean currents
Thousands of shipping containers vanish every year—what becomes of them?
A Million-Panel Project
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A Million-Panel Project
- Earth
- Earth Observatory
- Image of the Day
- EO Explorer
- Topics
- More Content
- About
Spin-Reversing Comet May Face Self-Destruction
Comets are known for providing breathtaking observations of their long and shiny tails when they travel too close to the Sun. This happens because comets are made of ice and primarily orbit far from the Sun, but as their icy core heats up it evaporates, resulting in the aforementioned breathtaking observations. But while evaporating comets make for great public photos, scientists who study comets are focused on these snowballs of gas and dust and how they are remnants of the origins of the solar system about 4.6 billion years ago.
Should Scientists Have Research "Reserves" on the Moon?
The worlds of the Solar System offer up exciting and (so far) mostly pristine places for planetary scientists to study. As space missions continue to travel to Mars, Europa, asteroids, and other worlds, questions keep coming up about keeping them safe for continued exploration and observations.
Curiosity Blog, Sols 4954–4960: Celebrating Our Rover Engineers Past and Present
- Curiosity Home
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3 min read
Curiosity Blog, Sols 4954–4960: Celebrating Our Rover Engineers Past and Present In this image acquired by NASA’s Mars rover Curiosity, the relatively light-toned bedrock in the foreground gives way to darker-toned rocks in the middle of the image, along what could be an erosional surface. Curiosity acquired the image using its Right Navigation Camera on July 15, 2026 — Sol 4955, or Martian day 4,955 of the Mars Science Laboratory mission — at 05:51:59 UTC. NASA/JPL-Caltech
Written by Lucy Thompson, Senior Research Scientist, University of New Brunswick, Canada
Earth planning date: Friday, July 17, 2026
As an APXS uplink lead and strategic planner, I have the privilege of working with the rover engineers most days that I am on operations. The APXS instrument measures the chemistry of rocks, unconsolidated materials and the atmosphere, and is situated on the end of Curiosity’s robotic arm. This means that any target of interest that we wish to analyze has to be safe to deploy the arm, APXS, and MAHLI (the closeup imager) to. We therefore rely on the rover engineers for their assessment and to sequence the arm moves to place us safely on the targets. Recently, our workspaces have been dusty with varied relief, but the rover engineers have successfully found areas that they have been able to brush and deploy APXS and MAHLI. This week was no exception, despite some of our workspaces appearing less than ideal upon initial observation. The team managed to find rock targets of interest (x5), which the rover engineers were able to safely place the arm on and brush so that we could analyze them with APXS and MAHLI. This ensures that we acquire high-quality compositional data and images as we continue our ascent of Mount Sharp, through rock layers of varying tone and texture, tracking potential changes in chemistry, and the depositional and alteration environment.
The rover engineers are also responsible for safely driving Curiosity to the areas of interest identified by the science team. They must assess the terrain for potential hazards such as large resistant blocks that could damage the rover wheels, sand/soil patches where we could get stuck, and high slopes that the rover could slip on. Despite unexpected damage to the wheels early in the mission and getting a little bogged down in some soil/sand just as we started to climb Mount Sharp, the engineers have successfully navigated us safely along more than 23 miles (37 kilometers) of drive distance and more than 4,400 feet (about 1.35 kilometers) of elevation gain. We recently requested to drive to specific locations in order to image what the team thinks could be an erosional surface within the Mg-sulfate/carbonate-bearing unit (see the image accompanying this post). Of course, the engineers were able to accommodate our desires, with the first stop crossed off in Monday’s plan, and the drive that is being planned this weekend taking us toward the next stop.
The rover engineers also ensure that our drilling activities execute safely and successfully, and are responsible for sequencing the arm motion required to deliver the drilled samples to our internal CheMin and SAM instruments. This required completely reconfiguring how we drill after a motor failed back in 2016, with extensive behind-the-scenes work at JPL for nearly a year and a half before we resumed. Curiosity has since drilled more than 20 rock targets.
So, thanks to the rover engineers and all the engineers and scientists on Curiosity’s team, we have had another full week of activities at Gale crater. We continue to track the chemistry, textures, tone and sedimentary structures of the sulfate/carbonate unit as we climb Mount Sharp and get ever closer to the Yardang unit with APXS, ChemCam, MAHLI and Mastcam. Curiosity continues to also monitor the local environment within Gale and the atmosphere in general.
-
Want to read more posts from the Curiosity team?
-
Want to learn more about Curiosity’s science instruments?
Article
2 weeks ago
4 min read Curiosity Blog, Sols 4941-4947: (Pin)Stripes on the Fourth of July
Article
2 weeks ago
2 min read Curiosity Blog, Sols 4934-4940: In the Land of the Polygons
Article
4 weeks ago
Keep Exploring Discover More Topics From NASA Mars
Mars is the fourth planet from the Sun, and the seventh largest. It’s the only planet we know of inhabited…
All Mars Resources
Explore this collection of Mars images, videos, resources, PDFs, and toolkits. Discover valuable content designed to inform, educate, and inspire,…
Rover Basics
Each robotic explorer sent to the Red Planet has its own unique capabilities driven by science. Many attributes of a…
Mars Exploration: Science Goals
The key to understanding the past, present or future potential for life on Mars can be found in NASA’s four…
Curiosity Blog, Sols 4954–4960: Celebrating Our Rover Engineers Past and Present
- Curiosity Home
- Science
- News and Features
- Multimedia
- Mars Missions
- Mars Home
3 min read
Curiosity Blog, Sols 4954–4960: Celebrating Our Rover Engineers Past and Present In this image acquired by NASA’s Mars rover Curiosity, the relatively light-toned bedrock in the foreground gives way to darker-toned rocks in the middle of the image, along what could be an erosional surface. Curiosity acquired the image using its Right Navigation Camera on July 15, 2026 — Sol 4955, or Martian day 4,955 of the Mars Science Laboratory mission — at 05:51:59 UTC. NASA/JPL-CaltechWritten by Lucy Thompson, Senior Research Scientist, University of New Brunswick, Canada
Earth planning date: Friday, July 17, 2026
As an APXS uplink lead and strategic planner, I have the privilege of working with the rover engineers most days that I am on operations. The APXS instrument measures the chemistry of rocks, unconsolidated materials and the atmosphere, and is situated on the end of Curiosity’s robotic arm. This means that any target of interest that we wish to analyze has to be safe to deploy the arm, APXS, and MAHLI (the closeup imager) to. We therefore rely on the rover engineers for their assessment and to sequence the arm moves to place us safely on the targets. Recently, our workspaces have been dusty with varied relief, but the rover engineers have successfully found areas that they have been able to brush and deploy APXS and MAHLI. This week was no exception, despite some of our workspaces appearing less than ideal upon initial observation. The team managed to find rock targets of interest (x5), which the rover engineers were able to safely place the arm on and brush so that we could analyze them with APXS and MAHLI. This ensures that we acquire high-quality compositional data and images as we continue our ascent of Mount Sharp, through rock layers of varying tone and texture, tracking potential changes in chemistry, and the depositional and alteration environment.
The rover engineers are also responsible for safely driving Curiosity to the areas of interest identified by the science team. They must assess the terrain for potential hazards such as large resistant blocks that could damage the rover wheels, sand/soil patches where we could get stuck, and high slopes that the rover could slip on. Despite unexpected damage to the wheels early in the mission and getting a little bogged down in some soil/sand just as we started to climb Mount Sharp, the engineers have successfully navigated us safely along more than 23 miles (37 kilometers) of drive distance and more than 4,400 feet (about 1.35 kilometers) of elevation gain. We recently requested to drive to specific locations in order to image what the team thinks could be an erosional surface within the Mg-sulfate/carbonate-bearing unit (see the image accompanying this post). Of course, the engineers were able to accommodate our desires, with the first stop crossed off in Monday’s plan, and the drive that is being planned this weekend taking us toward the next stop.
The rover engineers also ensure that our drilling activities execute safely and successfully, and are responsible for sequencing the arm motion required to deliver the drilled samples to our internal CheMin and SAM instruments. This required completely reconfiguring how we drill after a motor failed back in 2016, with extensive behind-the-scenes work at JPL for nearly a year and a half before we resumed. Curiosity has since drilled more than 20 rock targets.
So, thanks to the rover engineers and all the engineers and scientists on Curiosity’s team, we have had another full week of activities at Gale crater. We continue to track the chemistry, textures, tone and sedimentary structures of the sulfate/carbonate unit as we climb Mount Sharp and get ever closer to the Yardang unit with APXS, ChemCam, MAHLI and Mastcam. Curiosity continues to also monitor the local environment within Gale and the atmosphere in general.
-
Want to read more posts from the Curiosity team?
-
Want to learn more about Curiosity’s science instruments?
Article
2 weeks ago
4 min read Curiosity Blog, Sols 4941-4947: (Pin)Stripes on the Fourth of July
Article
2 weeks ago
2 min read Curiosity Blog, Sols 4934-4940: In the Land of the Polygons
Article
4 weeks ago
Keep Exploring Discover More Topics From NASA Mars
Mars is the fourth planet from the Sun, and the seventh largest. It’s the only planet we know of inhabited…
All Mars Resources
Explore this collection of Mars images, videos, resources, PDFs, and toolkits. Discover valuable content designed to inform, educate, and inspire,…
Rover Basics
Each robotic explorer sent to the Red Planet has its own unique capabilities driven by science. Many attributes of a…
Mars Exploration: Science Goals
The key to understanding the past, present or future potential for life on Mars can be found in NASA’s four…
Hubble Discovers the First "Missing" Black Hole in this Famous Star Cluster
Combining over 20 years of archival data from Hubble with new data from the James Webb Space Telescope, a team of astronomers has found the first of the "missing" black holes.