Members Can Post Anonymously On This Site
Venus: Earth’s Evil Twin Revealed | The Hottest Planet Explained
-
Similar Topics
-
By NASA
3 min read
January’s Night Sky Notes: The Red Planet
by Kat Troche of the Astronomical Society of the Pacific
Have you looked up at the night sky this season and noticed a bright object sporting a reddish hue to the left of Orion? This is none other than the planet Mars! January will be an excellent opportunity to spot this planet and some of its details with a medium-sized telescope. Be sure to catch these three events this month.
Martian Retrograde
Mars entered retrograde (or backward movement relative to its usual direction) on December 7, 2024, and will continue throughout January into February 23, 2025. You can track the planet’s progress by sketching or photographing Mars’ position relative to nearby stars. Be consistent with your observations, taking them every few nights or so as the weather permits. You can use free software like Stellarium or Stellarium Web (the browser version) to help you navigate the night as Mars treks around the sky. You can find Mars above the eastern horizon after 8:00 PM local time.
This mid-January chart shows the path of Mars from September 2024 to June 2025 as it enters and then exits in retrograde motion. Mars appears to change its direction of motion in the sky because Earth is passing the slower-moving Mars in its orbit. Stellarium Hide and Seek
On the night of January 13th, you can watch Mars ‘disappear’ behind the Moon during an occultation. An occultation is when one celestial object passes directly in front of another, hiding the background object from view. This can happen with planets and stars in our night sky, depending on the orbit of an object and where you are on Earth, similar to eclipses.
A simulated view of the Moon as Mars begins its occultation on January 13, 2025. Stellarium Depending on where you are within the contiguous United States, you can watch this event with the naked eye, binoculars, or a small telescope. The occultation will happen for over an hour in some parts of the US. You can use websites like Stellarium Web or the Astronomical League’s ‘Moon Occults Mars’ chart to calculate the best time to see this event.
Closer and Closer
As you observe Mars this month to track its retrograde movement, you will notice that it will increase in brightness. This is because Mars will reach opposition by the evening of January 16th. Opposition happens when a planet is directly opposite the Sun, as seen from Earth. You don’t need to be in any specific city to observe this event; you only need clear skies to observe that it gets brighter. It’s also when Mars is closest to Earth, so you’ll see more details in a telescope.
Want a quick and easy way to illustrate what opposition is for Jupiter, Saturn, Mars, or other outer worlds? Follow the instructions on our Toolkit Hack: Illustrating Opposition with Exploring the Solar System page using our Exploring Our Solar System activity!
A mosaic of the Valles Marineris hemisphere of Mars projected into point perspective, a view similar to that which one would see from a spacecraft. The mosaic is composed of 102 Viking Orbiter images of Mars. NASA/JPL-Caltech Mars has fascinated humanity for centuries, with its earliest recorded observations dating back to the Bronze Age. By the 17th century, astronomers were able to identify features of the Martian surface, such as its ice caps and darker regions. Since the 1960s, exploration of the Red Planet has intensified with robotic missions from various space organizations. Currently, NASA has five active missions, including rovers and orbiters, with the future focused on human exploration and habitation. Mars will always fill us with a sense of wonder and adventure as we reach for its soil through initiatives such as the Moon to Mars Architecture and the Mars Sample Return campaign.
View the full article
-
By European Space Agency
Our understanding of planet formation in the Universe’s early days is challenged by new data from the NASA/ESA/CSA James Webb Space Telescope. Webb solved a puzzle by proving a controversial finding made with the NASA/ESA Hubble Space Telescope more than 20 years ago.
View the full article
-
By NASA
Webb Webb News Latest News Latest Images Blog (offsite) Awards X (offsite – login reqd) Instagram (offsite – login reqd) Facebook (offsite- login reqd) Youtube (offsite) Overview About Who is James Webb? Fact Sheet Impacts+Benefits FAQ Science Overview and Goals Early Universe Galaxies Over Time Star Lifecycle Other Worlds Observatory Overview Launch Orbit Mirrors Sunshield Instrument: NIRCam Instrument: MIRI Instrument: NIRSpec Instrument: FGS/NIRISS Optical Telescope Element Backplane Spacecraft Bus Instrument Module Multimedia About Webb Images Images Videos What is Webb Observing? 3d Webb in 3d Solar System Podcasts Webb Image Sonifications Team International Team People Of Webb More For the Media For Scientists For Educators For Fun/Learning 7 Min Read NASA’s Webb Finds Planet-Forming Disks Lived Longer in Early Universe
This is a James Webb Space Telescope image of NGC 346, a massive star cluster in the Small Magellanic Cloud, a dwarf galaxy that is one of the Milky Way’s nearest neighbors. Credits:
NASA, ESA, CSA, STScI, Olivia C. Jones (UK ATC), Guido De Marchi (ESTEC), Margaret Meixner (USRA) NASA’s James Webb Space Telescope just solved a conundrum by proving a controversial finding made with the agency’s Hubble Space Telescope more than 20 years ago.
In 2003, Hubble provided evidence of a massive planet around a very old star, almost as old as the universe. Such stars possess only small amounts of heavier elements that are the building blocks of planets. This implied that some planet formation happened when our universe was very young, and those planets had time to form and grow big inside their primordial disks, even bigger than Jupiter. But how? This was puzzling.
To answer this question, researchers used Webb to study stars in a nearby galaxy that, much like the early universe, lacks large amounts of heavy elements. They found that not only do some stars there have planet-forming disks, but that those disks are longer-lived than those seen around young stars in our Milky Way galaxy.
“With Webb, we have a really strong confirmation of what we saw with Hubble, and we must rethink how we model planet formation and early evolution in the young universe,” said study leader Guido De Marchi of the European Space Research and Technology Centre in Noordwijk, Netherlands.
Image A: Protoplanetary Disks in NGC 346 (NIRCam Image)
This is a James Webb Space Telescope image of NGC 346, a massive star cluster in the Small Magellanic Cloud, a dwarf galaxy that is one of the Milky Way’s nearest neighbors. With its relative lack of elements heavier than hydrogen and helium, the NGC 346 cluster serves as a nearby proxy for studying stellar environments with similar conditions in the early, distant universe. Ten, small, yellow circles overlaid on the image indicate the positions of the ten stars surveyed in this study. NASA, ESA, CSA, STScI, Olivia C. Jones (UK ATC), Guido De Marchi (ESTEC), Margaret Meixner (USRA) A Different Environment in Early Times
In the early universe, stars formed from mostly hydrogen and helium, and very few heavier elements such as carbon and iron, which came later through supernova explosions.
“Current models predict that with so few heavier elements, the disks around stars have a short lifetime, so short in fact that planets cannot grow big,” said the Webb study’s co-investigator Elena Sabbi, chief scientist for Gemini Observatory at the National Science Foundation’s NOIRLab in Tucson. “But Hubble did see those planets, so what if the models were not correct and disks could live longer?”
To test this idea, scientists trained Webb on the Small Magellanic Cloud, a dwarf galaxy that is one of the Milky Way’s nearest neighbors. In particular, they examined the massive, star-forming cluster NGC 346, which also has a relative lack of heavier elements. The cluster served as a nearby proxy for studying stellar environments with similar conditions in the early, distant universe.
Hubble observations of NGC 346 from the mid 2000s revealed many stars about 20 to 30 million years old that seemed to still have planet-forming disks around them. This went against the conventional belief that such disks would dissipate after 2 or 3 million years.
“The Hubble findings were controversial, going against not only empirical evidence in our galaxy but also against the current models,” said De Marchi. “This was intriguing, but without a way to obtain spectra of those stars, we could not really establish whether we were witnessing genuine accretion and the presence of disks, or just some artificial effects.”
Now, thanks to Webb’s sensitivity and resolution, scientists have the first-ever spectra of forming, Sun-like stars and their immediate environments in a nearby galaxy.
“We see that these stars are indeed surrounded by disks and are still in the process of gobbling material, even at the relatively old age of 20 or 30 million years,” said De Marchi. “This also implies that planets have more time to form and grow around these stars than in nearby star-forming regions in our own galaxy.”
Image B: Protoplanetary Disks in NGC 346 Spectra (NIRSpec)
This graph shows, on the bottom left in yellow, a spectrum of one of the 10 target stars in this study (as well as accompanying light from the immediate background environment). Spectral fingerprints of hot atomic helium, cold molecular hydrogen, and hot atomic hydrogen are highlighted. On the top left in magenta is a spectrum slightly offset from the star that includes only light from the background environment. This second spectrum lacks a spectral line of cold molecular hydrogen.
On the right is the comparison of the top and bottom lines. This comparison shows a large peak in the cold molecular hydrogen coming from the star but not its nebular environment. Also, atomic hydrogen shows a larger peak from the star. This indicates the presence of a protoplanetary disk immediately surrounding the star. The data was taken with the microshutter array on the James Webb Space Telescope’s NIRSpec (Near-Infrared Spectrometer) instrument. Illustration: NASA, ESA, CSA, Joseph Olmsted (STScI) A New Way of Thinking
This finding refutes previous theoretical predictions that when there are very few heavier elements in the gas around the disk, the star would very quickly blow away the disk. So the disk’s life would be very short, even less than a million years. But if a disk doesn’t stay around the star long enough for the dust grains to stick together and pebbles to form and become the core of a planet, how can planets form?
The researchers explained that there could be two distinct mechanisms, or even a combination, for planet-forming disks to persist in environments scarce in heavier elements.
First, to be able to blow away the disk, the star applies radiation pressure. For this pressure to be effective, elements heavier than hydrogen and helium would have to reside in the gas. But the massive star cluster NGC 346 only has about ten percent of the heavier elements that are present in the chemical composition of our Sun. Perhaps it simply takes longer for a star in this cluster to disperse its disk.
The second possibility is that, for a Sun-like star to form when there are few heavier elements, it would have to start from a larger cloud of gas. A bigger gas cloud will produce a bigger disk. So there is more mass in the disk and therefore it would take longer to blow the disk away, even if the radiation pressure were working in the same way.
“With more matter around the stars, the accretion lasts for a longer time,” said Sabbi. “The disks take ten times longer to disappear. This has implications for how you form a planet, and the type of system architecture that you can have in these different environments. This is so exciting.”
The science team’s paper appears in the Dec. 16 issue of The Astrophysical Journal.
Image C: NGC 346: Hubble and Webb Observations
Image Before/After The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt manages the telescope and mission operations. Lockheed Martin Space, based in Denver also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Downloads
Right click any image to save it or open a larger version in a new tab/window via the browser’s popup menu.
View/Download all image products at all resolutions for this article from the Space Telescope Science Institute.
View/Download the science paper from the The Astrophysical Journal.
Media Contacts
Laura Betz – laura.e.betz@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Ann Jenkins – jenkins@stsci.edu, Christine Pulliam – cpulliam@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
Related Information
Past releases on NGC 346: Webb NIRCam image and MIRI image
Article: Highlighting other Webb Star Formation Discoveries
Simulation Video: Planetary Systems and Origins of Life
Animation Video: Exploring star and planet formation (English), and in Spanish
More Images of NGC 346 on AstroPix
More Webb News
More Webb Images
Webb Science Themes
Webb Mission Page
Related For Kids
What is a planet?
What is the Webb Telescope?
SpacePlace for Kids
En Español
¿Qué es un planeta?
Ciencia de la NASA
NASA en español
Space Place para niños
Keep Exploring Related Topics
James Webb Space Telescope
Webb is the premier observatory of the next decade, serving thousands of astronomers worldwide. It studies every phase in the…
Stars
Galaxies
Universe
Share
Details
Last Updated Dec 15, 2024 Editor Marty McCoy Contact Laura Betz laura.e.betz@nasa.gov Related Terms
Astrophysics Galaxies Galaxies, Stars, & Black Holes Goddard Space Flight Center James Webb Space Telescope (JWST) Science & Research Stars The Universe View the full article
-
By NASA
5 Min Read NASA DAVINCI Mission’s Many ‘Firsts’ to Unlock Venus’ Hidden Secrets
The surface of Venus is an inferno with temperatures hot enough to melt lead. This image is a composite of data from NASA’s Magellan spacecraft and Pioneer Venus Orbiter. Credits:
NASA/JPL-Caltech NASA’s DAVINCI — Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging — mission embodies the spirit of innovation and exploration that its namesake, Leonardo da Vinci, was famous for.
Scheduled to launch in the early 2030s, DAVINCI will explore Venus with both a spacecraft and a descent probe. DAVINCI’s probe will be the first in the 21st century to brave Venus’ atmosphere as it descends from above the planet’s clouds down to its surface. Two other missions, NASA’s VERITAS and ESA’s (European Space Agency) Envision, will also explore Venus in the 2030s from the planet’s orbit.
The DAVINCI spacecraft will study Venus’ clouds and highlands during two flybys. It also will release a spherical probe, about 3 feet wide, that will plunge through the planet’s thick atmosphere and corrosive clouds, taking measurements and capturing high-resolution images of the Venusian surface as it descends below the clouds.
Here are some of DAVINCI’s coming “firsts” in Venus exploration:
Exploring Solar System’s One-of-a-Kind Terrain
The DAVINCI mission will be the first to closely explore Alpha Regio, a region known as a “tessera.” So far found only on Venus, where they make up about 8% of the surface, tesserae are highland regions similar in appearance to rugged mountains on Earth. Previous missions discovered these features using radar instruments, but of the many international spacecraft that dove through Venus’ atmosphere between 1966 and 1985, none studied or photographed tesserae.
Thought to be ancient continents, tesserae like Alpha Regio may be among the oldest surfaces on the planet, offering scientists access to rocks that are billions of years old.
By studying these rocks from above Alpha Regio, DAVINCI scientists may learn whether ancient Venus had continents and oceans, and how water may have influenced the surface.
Photographing One of the Oldest Surfaces on Venus
The DAVINCI probe will capture the first close-up views of Alpha Regio with its infrared and optical cameras; these will also be the first photos of the planet’s surface taken in more than 40 years.
With surface temperatures reaching 900° F and air pressure 90 times that of Earth’s, Venus’ harsh environment makes exploration challenging, while its opaque atmosphere obscures direct views. Typically, scientists rely on radar instruments from Earth or Venus-orbiting spacecraft to study its terrain.
But DAVINCI’s probe will descend through the atmosphere and below the clouds for a clear view of the mountains and plains. It will capture images comparable to an airplane’s landing view of Earth’s surface. Scientists will use the photos to compile 3D maps of Alpha Regio that will provide more detail than ever of Venus’ terrain, helping them look for rocks that are usually only made in association with water.
Unveiling Secrets of Venus’ Mysterious Lower Atmosphere
The DAVINCI mission will be the first to analyze the chemical composition of Venus’ lower atmosphere through measurements taken at regular intervals, starting from approximately 90,000 feet above the surface and continuing until just before impact.
This region is critical because it contains gases and chemical compounds that may originate from Venus’ lower clouds, surface, or even subsurface.
For example, sulfur compounds detected here could indicate whether Venusian volcanoes are currently active or were active in the recent past. Noble gases (like helium or xenon), on the other hand, remain chemically inert and maintain stable concentrations, offering invaluable clues about Venus’ ancient history, such as the planet’s past water inventory.
By comparing Venus’ noble gas composition with that of Earth and Mars, scientists can better understand why these planets — despite forming from similar starting materials — evolved into dramatically different worlds.
Moreover, DAVINCI’s measurements of isotopes and trace gases in the lower atmosphere will shed light on Venus’ water history, from ancient times to the present, and the processes that triggered the planet’s extreme greenhouse effect.
State-of-the-Art Technology to Study Venus in Detail
Thanks to modern technology, the DAVINCI probe will be able to do things 1980s-era spacecraft couldn’t.
The descent probe will be better equipped than previous probes to protect the sensitive electronics inside of it, as it will be lined on the inside with high-temperature, multi-layer insulation — layers of advanced ceramic and silica fabrics separated by aluminum sheets.
Venus’ super thick atmosphere will slow the probe’s descent, but a parachute will also be released to slow it down further. Most Earth-friendly parachute fabrics, like nylon, would dissolve in Venus’ sulfuric acid clouds, so DAVINCI will have to use a different type of material than previous Venus missions did: one that’s resistant to acids and five times stronger than steel.
Read More: Old Data Yields New Secrets as NASA’s DAVINCI Preps for Venus Trip
By Lauren Colvin, with Lonnie Shekhtman
NASA’s Goddard Space Flight Center, Greenbelt, Md.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is the principal investigator institution for DAVINCI and will perform project management for the mission, provide science instruments, as well as project systems engineering to develop the in-situ probe flight system that will enter the atmosphere of Venus. Goddard also leads the overall science for the mission with an external science team from across the United States. Lockheed Martin Space in Denver, Colorado, will build the carrier/relay spacecraft. DAVINCI is a mission within the Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.
View the full article
-
By NASA
Artist’s concept depicts new research that has expanded our understanding of exoplanet WASP-69 b’s “tail.” NASA/JPL-Caltech/R. Hurt (IPAC) The Planet
WASP-69 b
The Discovery
The exoplanet WASP-69 b has a “tail,” leaving a trail of gas in its wake.
Key Takeaway
WASP-69 b is slowly losing its atmosphere as light hydrogen and helium particles in the planet’s outer atmosphere escape the planet over time. But those gas particles don’t escape evenly around the planet, instead they are swept into a tail of gas by the stellar wind coming from the planet’s star.
Details
Hot Jupiters like WASP-69 b are super-hot gas giants orbiting their host stars closely. When radiation coming from a star heats up a planet’s outer atmosphere, the planet can experience photoevaporation, a process in which lightweight gases like hydrogen and helium are heated by this radiation and launched outward into space. Essentially, WASP-69 b’s star strips gas from the planet’s outer atmosphere over time.
What’s more, something called the stellar wind can shape this escaping gas into an exoplanetary tail.
The stellar wind is a continuous stream of charged particles that flow outwards into space from a star’s outer atmosphere, or corona. On Earth, the Sun’s stellar wind interacts with our planet’s magnetic field which can create beautiful auroras like the Northern Lights.
On WASP-69 b, the stellar wind coming from its host star actually shapes the gas escaping from the planet’s outer atmosphere. So, instead of gas just escaping evenly around the planet, “strong stellar winds can sculpt that outflow in tails that trail behind the planet,” said lead author Dakotah Tyler, an astrophysicist at the University of California, Los Angeles, likening this gaseous tail to a comet’s tail.
Because this tail is created by the stellar wind, however, that means it’s subject to change.
“If the stellar wind were to taper down, then you could imagine that the planet is still losing some of its atmosphere, but it just isn’t getting shaped into the tail,” Tyler said, adding that, without the stellar wind, that gas escaping on all sides of the planet would be spherical and symmetrical. “But if you crank up the stellar wind, that atmosphere then gets sculpted into a tail.”
Tyler likened the process to a windsock blowing in the breeze, with the sock forming a more structured shape when the wind picks up and it fills with air.
The tail that Tyler and his research team observed on WASP-69 b extended more than 7.5 times the radius of the planet, or over 350,000 miles. But it’s possible that the tail is even longer. The team had to end observations with the telescope before the tail’s signal disappeared, so this measurement is a lower limit on the tail’s true length at the time.
However, keep in mind that because the tail is influenced by the stellar wind, changes in the stellar wind could change the tail’s size and shape over time. Additionally changes in the stellar wind influence the tail’s size and shape, but since the tail is visible when illuminated by starlight, changes in stellar activity can also affect tail observations.
Exoplanet tails are still a bit mysterious, especially because they are subject to change. The study of exoplanet tails could help scientists to better understand how these tails form as well as the ever-changing relationship between the stellar and planetary atmospheres. Additionally, because these exoplanetary tails are shaped by stellar activity, they could serve as indicators of stellar behavior over time. This could be helpful for scientists as they seek to learn more about the stellar winds of stars other than the star we know the most about, our very own Sun.
Fun Facts
WASP-69 b is losing a lot of gas — about 200,000 tons per second. But it’s losing this gaseous atmosphere very slowly — so slowly in fact that there is no danger of the planet being totally stripped or disappearing. In general, every billion years, the planet is losing an amount of material that equals the mass of planet Earth.
The solar system that WASP-69 b inhabits is about 7 billion years old, so even though the rate of atmosphere loss will vary over time, you might estimate that this planet has lost the equivalent of seven Earths (in mass) of gas over that period.
The Discoverers
A team of scientists led by Dakotah Tyler of the University of California, Los Angeles published a paper in January, 2024 on their discovery, “WASP-69b’s Escaping Envelope Is Confined to a Tail Extending at Least 7 Rp,” in the journal, “The Astrophysical Journal.” The observations described in this paper were made by Keck/NIRSPEC (NIRSPEC is a spectrograph designed for Keck II).
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.