Feed aggregator
Summer Triangle Corner: Altair
3 min read
Summer Triangle Corner: Altair A map of the asterism known as the Summer Triangle. This asterism is made up of three stars: Vega in the Lyra constellation, Altair in the Aquila constellation, and Deneb in the Cygnus constellation. Stellarium Web
Altair is the last stop on our trip around the Summer Triangle! The last star in the asterism to rise for Northern Hemisphere observers before summer begins, brilliant Altair is high overhead at sunset at the end of the season in September. Altair might be the most unusual of the three stars of the Triangle, due to its great speed: this star spins so rapidly that it appears “squished.”
Altair is the brightest star in the constellation of Aquila, the Eagle. A very bright star, Altair holds a notable place in the mythologies of cultures around the world. As discussed in a previous article, Altair represents the cowherd in the ancient tale “Cowherd and the Weaver Girl.” While described as part of an eagle by ancient peoples around the Mediterranean, it was also seen as part of an eagle by the Koori people in Australia. They saw the star itself as representing a wedge-tailed eagle, and two nearby stars as his wives, a pair of black swans. More recently, one of the first home computers was named after the star: the Altair 8800.
A rapidly spinning star darkens and exhibits a bulge at the equator, as shown by the model at left. At right, an actual CHARA interferometer image of the star Altair. NASA/NSF/Center for High Angular Resolution Astronomy/Zina Deretsky
Altair’s rapid spinning was first detected in the 1960s. The close observations that followed tested the limits of technology available to astronomers, eventually resulting in direct images of the star’s shape and surface by using a technique called interferometry, which combines the light from two or more instruments to produce a single image. Predictions about how the surface of a rapidly spinning massive star would appear held true to the observations; models predicted a squashed, almost “pumpkin-like” shape instead of a round sphere, along with a dimming effect along the widened equator, and the observations confirmed this!
This equatorial dimming is due to a phenomenon called gravity darkening. Altair is wider at the equator than it is at the poles due to centrifugal force, resulting in the star’s mass bulging outwards at the equator. This results in the denser poles of the star being hotter and brighter, and the less dense equator being cooler and therefore dimmer. This doesn’t mean that the equator of Altair or other rapidly spinning stars are actually dark, but rather that the equator is dark in comparison to the poles; this is similar in a sense to sunspots. If you were to observe a sunspot on its own, it would appear blindingly bright, but it is cooler than the surrounding plasma in the Sun and so appears dark in contrast.
As summer winds down, you can still take a Trip Around the Summer Triangle with this activity from the Night Sky Network. Mark some of the sights in and around the Summer Triangle at: bit.ly/TriangleTrip.
Originally posted by Dave Prosper: August 2020
Last Updated by Kat Troche: July 2025
Summer Triangle Corner: Altair
3 min read
Summer Triangle Corner: Altair A map of the asterism known as the Summer Triangle. This asterism is made up of three stars: Vega in the Lyra constellation, Altair in the Aquila constellation, and Deneb in the Cygnus constellation. Stellarium WebAltair is the last stop on our trip around the Summer Triangle! The last star in the asterism to rise for Northern Hemisphere observers before summer begins, brilliant Altair is high overhead at sunset at the end of the season in September. Altair might be the most unusual of the three stars of the Triangle, due to its great speed: this star spins so rapidly that it appears “squished.”
Altair is the brightest star in the constellation of Aquila, the Eagle. A very bright star, Altair holds a notable place in the mythologies of cultures around the world. As discussed in a previous article, Altair represents the cowherd in the ancient tale “Cowherd and the Weaver Girl.” While described as part of an eagle by ancient peoples around the Mediterranean, it was also seen as part of an eagle by the Koori people in Australia. They saw the star itself as representing a wedge-tailed eagle, and two nearby stars as his wives, a pair of black swans. More recently, one of the first home computers was named after the star: the Altair 8800.
A rapidly spinning star darkens and exhibits a bulge at the equator, as shown by the model at left. At right, an actual CHARA interferometer image of the star Altair. NASA/NSF/Center for High Angular Resolution Astronomy/Zina DeretskyAltair’s rapid spinning was first detected in the 1960s. The close observations that followed tested the limits of technology available to astronomers, eventually resulting in direct images of the star’s shape and surface by using a technique called interferometry, which combines the light from two or more instruments to produce a single image. Predictions about how the surface of a rapidly spinning massive star would appear held true to the observations; models predicted a squashed, almost “pumpkin-like” shape instead of a round sphere, along with a dimming effect along the widened equator, and the observations confirmed this!
This equatorial dimming is due to a phenomenon called gravity darkening. Altair is wider at the equator than it is at the poles due to centrifugal force, resulting in the star’s mass bulging outwards at the equator. This results in the denser poles of the star being hotter and brighter, and the less dense equator being cooler and therefore dimmer. This doesn’t mean that the equator of Altair or other rapidly spinning stars are actually dark, but rather that the equator is dark in comparison to the poles; this is similar in a sense to sunspots. If you were to observe a sunspot on its own, it would appear blindingly bright, but it is cooler than the surrounding plasma in the Sun and so appears dark in contrast.
As summer winds down, you can still take a Trip Around the Summer Triangle with this activity from the Night Sky Network. Mark some of the sights in and around the Summer Triangle at: bit.ly/TriangleTrip.
Originally posted by Dave Prosper: August 2020
Last Updated by Kat Troche: July 2025
What Is Experimental Archaeology? Sam Kean Explores Ancient Tools, Surgeries and Feasts in Dinner with King Tut
In his new book, Sam Kean reveals how re-creating ancient tools, techniques and traditions can unlock secrets about how our ancestors lived—and what they felt.
What if we've been thinking about dark matter all wrong, scientist wonders
This Week's Sky at a Glance, August 15 – 24
Saturn glows through the evening near the Andromegasus Dipper. Venus and Jupiter, drawing apart, still light the dawn dramatically. The Moon joins them.
The post This Week's Sky at a Glance, August 15 – 24 appeared first on Sky & Telescope.
Curiosity Blog, Sols 4627-4628: A Ridge Stop in the Boxworks
- Curiosity Home
- Science
- News and Features
- Multimedia
- Mars Missions
- Mars Home
2 min read
Curiosity Blog, Sols 4627-4628: A Ridge Stop in the Boxworks NASA’s Mars rover Curiosity acquired this close-up view of the rock target “Bococo” at the intersection of several boxwork ridges, showing bright millimeter-scale nodules likely to be calcium sulfate. Curiosity acquired this image using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover’s robotic arm, which uses an onboard focusing process to merge multiple images of the same target, acquired at different focus positions, to bring all (or, as many as possible) features into focus in a single image. Curiosity performed the merge on Aug. 10, 2025 — Sol 4625, or Martian day 4,625 of the Mars Science Laboratory mission — at 08:00:39 UTC. NASA/JPL-Caltech/MSSS
Earth planning date: Monday Aug. 11, 2025
Written by Lucy Lim, Planetary Scientist at NASA’s Goddard Space Flight Center
On the Curiosity team, we’re continuing our exploration of the boxwork-forming region in Gale Crater. A successful 25-meter drive (about 82 feet) brought the rover from the “peace sign” ridge intersection to a new ridge site. Several imaging investigations were pursued in today’s plan, including Mastcam observations of a potential incipient hollow (“Laguna Miniques”), and of a number of troughs to examine how fractures transition from bedrock to regolith.
With six wheels on the ground, Curiosity was also ready to deploy the rover arm for some contact science. APXS and MAHLI measurements were planned to explore the local bedrock at two points with a brushed (DRT) measurement (“Santa Catalina”) and a non-DRT measurement (“Puerto Teresa”). A third MAHLI observation will be co-targeted with one of the LIBS geochemical measurements on a light-toned block, “Palma Seca.” Because we’re in nominal sols for this plan, we were able to plan a second targeted LIBS activity to measure the composition of a high-relief feature on another block, “Yavari” before the drive.
The auto-targeted LIBS (AEGIS) that executed post-drive on sol 4626 had fallen on a bedrock target and will be documented in high resolution via Mastcam imaging.
Two long-distance imaging mosaics were planned for the ChemCam remote imager (RMI): one on a potential scarp and lens in sediments exposed on the “Mishe Mokwa” butte in the strata above the rover’s current position, and the second on an east-facing boxwork ridge with apparently exposed cross-bedding that may be related to the previously explored “Volcán Peña Blanca” ridge.
As usual, the modern Martian environment will also be observed with camera measurements of the atmospheric opacity, a Navcam movie to watch for dust lifting, and the usual REMS and DAN passive monitoring of the temperature, humidity, and neutron flux at the rover’s location.
The next drive is planned to bring us to a spot in a hollow where we hope to plan contact science on the erosionally recessive hollow bedrock in addition to imaging with a good view of the rock layers exposed in the wall of another prominent ridge.
-
Want to read more posts from the Curiosity team?
-
Want to learn more about Curiosity’s science instruments?
Article
1 hour ago
2 min read Curiosity Blog, Sols 4624-4626: A Busy Weekend at the Boxwork
Article
5 days ago
2 min read Linking Local Lithologies to a Larger Landscape
Article
2 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 4627-4628: A Ridge Stop in the Boxworks
- Curiosity Home
- Science
- News and Features
- Multimedia
- Mars Missions
- Mars Home
2 min read
Curiosity Blog, Sols 4627-4628: A Ridge Stop in the Boxworks NASA’s Mars rover Curiosity acquired this close-up view of the rock target “Bococo” at the intersection of several boxwork ridges, showing bright millimeter-scale nodules likely to be calcium sulfate. Curiosity acquired this image using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover’s robotic arm, which uses an onboard focusing process to merge multiple images of the same target, acquired at different focus positions, to bring all (or, as many as possible) features into focus in a single image. Curiosity performed the merge on Aug. 10, 2025 — Sol 4625, or Martian day 4,625 of the Mars Science Laboratory mission — at 08:00:39 UTC. NASA/JPL-Caltech/MSSSEarth planning date: Monday Aug. 11, 2025
Written by Lucy Lim, Planetary Scientist at NASA’s Goddard Space Flight Center
On the Curiosity team, we’re continuing our exploration of the boxwork-forming region in Gale Crater. A successful 25-meter drive (about 82 feet) brought the rover from the “peace sign” ridge intersection to a new ridge site. Several imaging investigations were pursued in today’s plan, including Mastcam observations of a potential incipient hollow (“Laguna Miniques”), and of a number of troughs to examine how fractures transition from bedrock to regolith.
With six wheels on the ground, Curiosity was also ready to deploy the rover arm for some contact science. APXS and MAHLI measurements were planned to explore the local bedrock at two points with a brushed (DRT) measurement (“Santa Catalina”) and a non-DRT measurement (“Puerto Teresa”). A third MAHLI observation will be co-targeted with one of the LIBS geochemical measurements on a light-toned block, “Palma Seca.” Because we’re in nominal sols for this plan, we were able to plan a second targeted LIBS activity to measure the composition of a high-relief feature on another block, “Yavari” before the drive.
The auto-targeted LIBS (AEGIS) that executed post-drive on sol 4626 had fallen on a bedrock target and will be documented in high resolution via Mastcam imaging.
Two long-distance imaging mosaics were planned for the ChemCam remote imager (RMI): one on a potential scarp and lens in sediments exposed on the “Mishe Mokwa” butte in the strata above the rover’s current position, and the second on an east-facing boxwork ridge with apparently exposed cross-bedding that may be related to the previously explored “Volcán Peña Blanca” ridge.
As usual, the modern Martian environment will also be observed with camera measurements of the atmospheric opacity, a Navcam movie to watch for dust lifting, and the usual REMS and DAN passive monitoring of the temperature, humidity, and neutron flux at the rover’s location.
The next drive is planned to bring us to a spot in a hollow where we hope to plan contact science on the erosionally recessive hollow bedrock in addition to imaging with a good view of the rock layers exposed in the wall of another prominent ridge.
-
Want to read more posts from the Curiosity team?
-
Want to learn more about Curiosity’s science instruments?
Article
2 days ago
2 min read Linking Local Lithologies to a Larger Landscape
Article
1 week ago
3 min read Curiosity Blog, Sols 4622-4623: Kicking Off (Earth) Year 14 With an Investigation of Veins
Article
1 week 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…
NASA Seeks Industry Feedback on Fission Surface Power
As part of the agency’s initiative to return humanity to the Moon and eventually send the first astronaut – an American – to Mars, NASA is surveying industry for interest and feedback on a fission surface power system, through a Request for Information issued Thursday.
Earlier this month, NASA declared its intent to put a nuclear reactor on the Moon by the mid-2030s to support lunar exploration, provide power generation on Mars, and strengthen national security in space.
“Today’s call for industry input is an important step toward engaging the commercial space industry in powering the lunar economy and enabling future human exploration on Mars,” said Steve Sinacore, Fission Surface Power program executive at NASA’s Glenn Research Center in Cleveland. “Developing a safe, reliable, and efficient power supply is key to unlocking the future of human space exploration and ensuring America retains its dominance in space.”
Building on its previous work, NASA will work with industry to design a fission surface power system that would provide at least 100 kilowatts of electrical power, have a mass allocation of less than 15 metric tons, and use a closed Brayton cycle power conversion system, which converts heat to electricity.
NASA’s new Fission Surface Power effort builds on more than 60 years of agency experience in exploration technology. In 2022, NASA awarded three contracts for fission surface power system concepts for the Moon. In addition, NASA has used nuclear power sources in spacecraft and rovers over the years.
The size, weight, and power capability of fission systems make them an effective continuous power supply regardless of location. Additionally, a nuclear reactor could be placed in lunar regions where sunlight cannot reach and could sustain nights on the Moon which can last more than 14 Earth days near the poles.
Nuclear power is a key element for NASA’s Artemis missions and supporting a robust lunar economy. The Request for Information invites innovators to contribute to this effort, allowing NASA to access industry expertise and bolstering American ingenuity.
Responses to the Request for Information are due Thursday, Aug. 21, and could be used to finalize a potential opportunity later this year.
The Fission Surface Power effort is managed through NASA Glenn. The power system development is funded by the agency’s Exploration Systems Development Mission Directorate Moon to Mars Program.
Share Details Last Updated Aug 15, 2025 LocationNASA Headquarters Related TermsNASA Seeks Industry Feedback on Fission Surface Power
As part of the agency’s initiative to return humanity to the Moon and eventually send the first astronaut – an American – to Mars, NASA is surveying industry for interest and feedback on a fission surface power system, through a Request for Information issued Thursday.
Earlier this month, NASA declared its intent to put a nuclear reactor on the Moon by the mid-2030s to support lunar exploration, provide power generation on Mars, and strengthen national security in space.
“Today’s call for industry input is an important step toward engaging the commercial space industry in powering the lunar economy and enabling future human exploration on Mars,” said Steve Sinacore, Fission Surface Power program executive at NASA’s Glenn Research Center in Cleveland. “Developing a safe, reliable, and efficient power supply is key to unlocking the future of human space exploration and ensuring America retains its dominance in space.”
Building on its previous work, NASA will work with industry to design a fission surface power system that would provide at least 100 kilowatts of electrical power, have a mass allocation of less than 15 metric tons, and use a closed Brayton cycle power conversion system, which converts heat to electricity.
NASA’s new Fission Surface Power effort builds on more than 60 years of agency experience in exploration technology. In 2022, NASA awarded three contracts for fission surface power system concepts for the Moon. In addition, NASA has used nuclear power sources in spacecraft and rovers over the years.
The size, weight, and power capability of fission systems make them an effective continuous power supply regardless of location. Additionally, a nuclear reactor could be placed in lunar regions where sunlight cannot reach and could sustain nights on the Moon which can last more than 14 Earth days near the poles.
Nuclear power is a key element for NASA’s Artemis missions and supporting a robust lunar economy. The Request for Information invites innovators to contribute to this effort, allowing NASA to access industry expertise and bolstering American ingenuity.
Responses to the Request for Information are due Thursday, Aug. 21, and could be used to finalize a potential opportunity later this year.
The Fission Surface Power effort is managed through NASA Glenn. The power system development is funded by the agency’s Exploration Systems Development Mission Directorate Moon to Mars Program.
Share Details Last Updated Aug 15, 2025 LocationNASA Headquarters Related TermsWas it cooked in space? A space food-themed quiz!
NASA plans to build a nuclear reactor on the moon — a space lawyer explains why, and what the law has to say
Why Are Rabbits Sprouting Tentacles?
Rabbits spotted with hornlike growths on their face in northern Colorado are doing better than they look
NASA's new sun-studying mission 'PUNCH' attains its final form in Earth orbit
Extremely cold atoms defy entropy and refuse to heat up
Extremely cold atoms defy entropy and refuse to heat up
Scientists created a new carbon molecule for the second time ever
Scientists created a new carbon molecule for the second time ever
How Telescope Noise Could Help Us Monitor Climate Change
University of Warwick astronomers, in partnership with institutions in Spain, are showing how astronomy tools, that are usually used to study stars, can be repurposed as climate sensors, helping us track how Earth's atmosphere is changing in the face of global warming.
The Europa Clipper Mission Tests it Radar Instrument at Mars
NASA's Europa Clipper, the largest interplanetary probe, tested its radar during a Mars flyby. The results show the kind of detailed imagery the probe will capture once it arrives at Jupiter’s moon Europa.