NASA Astronomy Picture of the Day

November 1, 2024

Spiral Galaxy NGC 6744

Big, beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo but appears as only a faint smudge in the eyepiece of a small telescope. We see the disk of the nearby island universe tilted towards our line of sight in this remarkably deep and detailed galaxy portrait, a telescopic image that spans an area about the angular size of a full moon. In it, the giant galaxy's elongated yellowish core is dominated by the light from old, cool stars. Beyond the core, grand spiral arms are filled with young blue star clusters and speckled with pinkish star forming regions. An extended arm sweeps past smaller satellite galaxy NGC 6744A at the upper left. NGC 6744's galactic companion is reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud.

https://apod.nasa.gov/apod/astropix.html

NASA’s Perseverance Captures ‘Googly Eye’ During Solar Eclipse

Oct 30, 2024

The tiny, potato-shaped moon Phobos, one of two Martian moons, cast a silhouette as it passed in front of the Sun, creating an eye in Mars’ sky.

From its perch on the western wall of Mars’ Jezero Crater, NASA’s Perseverance rover recently spied a “googly eye” peering down from space.

The pupil in this celestial gaze is the Martian moon Phobos, and the iris is our Sun.

Captured by the rover’s Mastcam-Z on Sept. 30, the 1,285th Martian day of Perseverance’s mission, the event took place when the potato-shaped moon passed directly between the Sun and a point on the surface of Mars, obscuring a large part of the Sun’s disc.

At the same time that Phobos appeared as a large black disc rapidly moving across the face of the Sun, its shadow, or antumbra, moved across the planet’s surface.

Astronomer Asaph Hall named the potato-shaped moon in 1877, after the god of fear and panic in Greek mythology; the word “phobia” comes from Phobos.

(And the word for fear of potatoes, and perhaps potato-shaped moons, is potnonomicaphobia.) He named Mars’ other moon Deimos, after Phobos’ mythological twin brother.

Roughly 157 times smaller in diameter than Earth’s Moon, Phobos is only about 17 miles (27 kilometers) at its widest point. Deimos is even smaller.

Rapid Transit

Because Phobos’ orbit is almost perfectly in line with the Martian equator and relatively close to the planet’s surface, transits of the moon occur on most days of the Martian year.

Due to its quick orbit (about 7.6 hours to do a full loop around Mars), a transit of Phobos usually lasts only 30 seconds or so.

This is not the first time that a NASA rover has witnessed Phobos blocking the Sun’s rays.

Perseverance has captured several Phobos transits since landing at Mars’ Jezero Crater in February 2021. Curiosity captured a video in 2019.

And Opportunity captured an image in 2004.

By comparing the various images, scientists can refine their understanding of the moon’s orbit to learn how it’s changing.

Phobos is getting closer to Mars and is predicted to collide with it in about 50 million years.

https://www.nasa.gov/missions/mars-2020-perseverance/perseverance-rover/nasas-perseverance-captures-googly-eye-during-solar-eclipse/

Sun Releases Strong Solar Flare

October 31, 2024

The Sun emitted a strong solar flare, peaking at 5:20 p.m. ET on Oct. 31, 2024. NASA’s Solar Dynamics Observatory, which watches the Sun constantly, captured an image of the event.

Solar flares are powerful bursts of energy. Flares and solar eruptions can impact radio communications, electric power grids, navigation signals, and pose risks to spacecraft and astronauts.

This flare is classified as an X2.0 flare. X-class denotes the most intense flares, while the number provides more information about its strength.

To see how such space weather may affect Earth, please visit NOAA’s Space Weather Prediction Center https://spaceweather.gov/, the U.S. government’s official source for space weather forecasts, watches, warnings, and alerts.

NASA works as a research arm of the nation’s space weather effort. NASA observes the Sun and our space environment constantly with a fleet of spacecraft that study everything from the Sun’s activity to the solar atmosphere, and to the particles and magnetic fields in the space surrounding Earth.

https://blogs.nasa.gov/solarcycle25/2024/10/31/sun-releases-strong-solar-flare-19/

https://www.spaceweather.gov/

International SWOT Satellite Spots Planet-Rumbling Greenland Tsunami

Oct 31, 2024

The international Surface Water and Ocean Topography (SWOT) satellite mission, a collaboration between NASA and France’s CNES (Centre National d’Études Spatiales), detected the unique contours of a tsunami that sloshed within the steep walls of a fjord in Greenland in September 2023.

Triggered by a massive rockslide, the tsunami generated a seismic rumble that reverberated around the world for nine days.

An international research team that included seismologists, geophysicists, and oceanographers recently reported on the event after a year of analyzing data.

The SWOT satellite collected water elevation measurements in Dickson Fjord on Sept. 17, 2023, the day after the initial rockslide and tsunami.

The data was compared with measurements made under normal conditions a few weeks prior, on Aug. 6, 2023.

In the data visualization (above), colors toward the red end of the scale indicate higher water levels, and blue colors indicate lower-than-normal levels.

The data suggests that water levels at some points along the north side of the fjord were as much as 4 feet (1.2 meters) higher than on the south.

“SWOT happened to fly over at a time when the water had piled up pretty high against the north wall of the fjord,” said Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California.

“Seeing the shape of the wave — that’s something we could never do before SWOT.”

In a paper published recently in Science, researchers traced a seismic signal back to a tsunami that began when more than 880 million cubic feet of rock and ice (25 million cubic meters) fell into Dickson Fjord.

Part of a network of channels on Greenland’s eastern coast, the fjord is about 1,772 feet (540 meters) deep and 1.7 miles (2.7 kilometers) wide, with walls taller than 6,000 feet (1,830 meters).

Far from the open ocean, in a confined space, the energy of the tsunami’s motion had limited opportunity to dissipate, so the wave moved back and forth about every 90 seconds for nine days.

It caused tremors recorded on seismic instruments thousands of miles away.

From about 560 miles (900 kilometers) above, SWOT uses its sophisticated Ka-band Radar Interferometer (KaRIn) instrument to measure the height of nearly all water on Earth’s surface, including the ocean and freshwater lakes, reservoirs, and rivers.

“This observation also shows SWOT’s ability to monitor hazards, potentially helping in disaster preparedness and risk reduction,” said SWOT program scientist Nadya Vinogradova Shiffer at NASA Headquarters in Washington.

It can also see into fjords, as it turns out.

“The KaRIn radar’s resolution was fine enough to make observations between the relatively narrow walls of the fjord,” said Lee-Lueng Fu, the SWOT project scientist.

“The footprint of the conventional altimeters used to measure ocean height is too large to resolve such a small body of water.”

https://www.nasa.gov/missions/swot/international-swot-satellite-spots-planet-rumbling-greenland-tsunami/

Witch Nebula Casts Starry Spell

Oct 31, 2024

This 2013 image taken by NASA’s Wide-Field Infrared Survey Explorer, or WISE, captures a nebula that looks like a witch screaming.

Perhaps that imagined scream is a creation spell, for the Witch Hat nebula’s billowy clouds are a star nursery.

We can see these clouds thanks to massive stars lighting them up; dust in the cloud is being hit with starlight, causing it to glow with infrared light, which was picked up by WISE’s detectors.

WISE launched to near-Earth orbit on Dec. 14, 2009, and surveyed the full sky in four infrared wavelength bands until the frozen hydrogen cooling the telescope was depleted in September 2010.

The spacecraft was placed into hibernation in February 2011, having completed its primary astrophysics mission.

In late 2013, the spacecraft was resurrected – no incantation needed – when NASA’s Planetary Science Division gave it a new mission and a new name: NEOWISE.

The spacecraft began helping NASA identify and describe near-Earth objects (NEOs).

NEOs are comets and asteroids that have been nudged into orbits that allow them to enter Earth’s neighborhood.

NEOWISE was decommissioned Aug. 8, 2024, and placed into hibernation for the last time, ending its career as an active asteroid hunter.

https://www.nasa.gov/image-article/witch-nebula-casts-starry-spell/

2024 Antarctic ozone hole ranks 7th-smallest since recovery began

October 30, 2024

Healing continues in the atmosphere over the Antarctic: A hole that opens annually in the ozone layer over Earth's southern pole was relatively small in 2024 compared to other years.

NOAA and NASA scientists project the ozone layer could fully recover by 2066.

During the peak of ozone depletion season from September 7 through October 13, the 2024 area of the ozone hole ranked the seventh-smallest since recovery began in 1992.

That’s when the Montreal Protocol, a landmark international agreement to phase out ozone-depleting chemicals, started to take effect.

At almost 8 million square miles (20 million square kilometers), the monthly average ozone-depleted region in the Antarctic this year was nearly three times the size of the contiguous U.S.

The hole reached its greatest one-day extent for the year on September 28 at 8.5 million square miles (22.4 million square kilometers).

The improvement this year is due to a combination of continuing declines in chlorofluorocarbons, an ozone-depleting chemical phased out by the Montreal Protocol, along with an unexpected infusion of ozone carried by air currents from north of the Antarctic, scientists said.

“The 2024 Antarctic hole is smaller than ozone holes seen in the early 2000s,” said Paul Newman, leader of NASA’s ozone research team and chief scientist for Earth sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“The gradual improvement we’ve seen in the past two decades shows that international efforts that curbed ozone-destroying chemicals are working.”

In previous years, NOAA and NASA have reported the ozone hole ranking using a time period dating back to 1979, when scientists started tracking Antarctic ozone levels with satellite data.

Using that longer record, which includes the years prior to recovery spurred by the Montreal Protocol, this year's hole ranked 20th-smallest in area across 45 years of observations.

The ozone-rich layer high in the atmosphere acts as a planetary sunscreen that helps shield us from harmful ultraviolet (UV) radiation from the sun.

Areas with depleted ozone allow more UV radiation through, resulting in increased cases of skin cancer and cataracts.

Excessive exposure to UV light can also reduce agricultural yields as well as damage aquatic plants and animals in vital ecosystems.

Scientists were alarmed in the 1970s at the prospect that chlorofluorocarbon (CFC) chemicals could eat away at atmospheric ozone.

By the mid-1980s, the ozone layer had been depleted so much that a broad swath of the Antarctic stratosphere was essentially devoid of ozone by early October each year.

Sources of damaging CFCs included coolants in refrigerators and air conditioners, as well as aerosols in hairspray, antiperspirant and spray paint.

CFCs were also released in the manufacture of insulating foams and as components of industrial fire suppression systems.

The Montreal Protocol was signed in 1987 to phase out CFC-based products and processes. Countries worldwide agreed to replace the chemicals with more environmentally-friendly alternatives by 2010.

The release of CFC compounds has dramatically decreased due to the Montreal Protocol. But CFCs already in the air will take many decades to break down.

As existing CFC levels gradually decline, ozone in the upper atmosphere will rebound globally, and ozone holes will shrink.

"For 2024, we can see that the ozone hole’s severity is below average compared to other years in the past three decades, but the ozone layer is still far from being fully healed,” said Stephen Montzka, senior scientist with NOAA’s Global Monitoring Laboratory.

Scientists expect atmospheric ozone to return to levels that eliminate holes over the poles in the second half of this century.

Researchers rely on a combination of systems to monitor the ozone layer.

They include instruments on NASA’s Aura satellite, and NOAA’s polar orbiting satellites: The NOAA-20 and NOAA-21 satellites and the Suomi National Polar-orbiting Partnership satellite, jointly operated by NOAA and NASA.

NOAA scientists also release instrumented weather balloons from the South Pole Baseline Atmospheric Observatory to observe ozone concentrations directly overhead in a measurement called Dobson Units.

The 2024 concentration reached its lowest value of 109 Dobson Units on October 5. The lowest value ever recorded over the South Pole was 92 Dobson Units in October 2006.

NASA and NOAA satellite observations of ozone concentrations cover the entire ozone hole, which can produce a slightly smaller value for the lowest Dobson Unit measurement.

"This is well below the 225 Dobson Units that was typical of the ozone cover above the Antarctic in 1979,” said NOAA Research Chemist Bryan Johnson.

https://www.noaa.gov/news-release/2024-antarctic-ozone-hole-ranks-7th-smallest-since-recovery-began

Frenchman and German arrested at Russian space site in Kazakhstan

November 1, 20244:44 AM PDT

A French man and a German man have been arrested for unauthorised entry to the Baikonur cosmodrome in Kazakhstan that Russia uses for space launches, Russian state media reported on Friday.

RIA news agency quoted a Kazakh prosecutor as saying the pair were detained for one day and then removed from the complex.

It said the 21-year-old Frenchman and 26-year-old German were tourists who undertook an "unauthorised walk" around the facility because they wanted to see a Russian Energiya rocket.

In July, two Dutch citizens and a Belgian were arrested while trying to enter Baikonur. The previous month, a French citizen died of dehydration while attempting to walk there.

The cosmodrome, which is leased from Kazakhstan by Russia, is located in a remote desert area and access to it is restricted, although tours are sold for those who want to witness a spacecraft launch.

https://www.reuters.com/world/frenchman-german-arrested-russian-space-site-kazakhstan-2024-11-01/

ISRO launches India’s first analog space mission in Leh: All about the project to simulate extraterrestrial life

1 Nov 2024, 04:10 PM IST

The Indian Space Research Organisation (ISRO) launched the country's first analog space mission in Leh, Ladakh, on Friday.

The mission was developed by a partnership of the Human Spaceflight Centre, ISRO, AAKA Space Studio, the University of Ladakh, and IIT Delhi.

It is also supported by the Ladakh Autonomous Hill Development Council.

ISRO announced the novel initiative while sharing the picture on X. “India’s first analog space mission kicks off in Leh!

A collaborative effort by Human Spaceflight Centre, ISRO, AAKA Space Studio, University of Ladakh, IIT Bombay, and supported by Ladakh Autonomous Hill Development Council, this mission will simulate life in an interplanetary habitat to tackle the challenges of a base station beyond Earth,” ISRO wrote on X.

The mission aims to simulate conditions similar to those on Mars and the Moon while considering Ladakh’s extreme climate and geographical terrain.

The mission tries to replicate the challenges that astronauts would face in extreme conditions of celestial bodies.

Ladakh is a cold desert and the climate is a mix of desert and arctic regions. The temperature in the region may range from 3 to 35 °C in summers and −20 to −35 °C in winters.

The region experiences heavy snowfall during winter.

According to NASA, analog missions are field tests in locations that are similar to extreme space environments.

"NASA engineers and scientists work with government agencies, academia, and industry to gather requirements for testing in harsh environments before they are used in space," NASA said.

The mission aims to save time, money and manpower by mimicking a similar environment on Earth before investing in space, it added.

These field tests include new technologies, robotic equipment, vehicles, habitats, communications, power generation, mobility, infrastructure, and storage.

Behavioural effects such as isolation and confinement, team dynamics, menu fatigue, and others, are also observed.

“Analog missions prepare us for near-term and future exploration to asteroids, Mars, and the Moon. Analogs play a significant role in problem-solving for spaceflight research,” NASA said.

https://www.livemint.com/news/isro-launches-indias-first-analog-space-mission-in-leh-all-about-the-project-to-simulate-extraterrestrial-life-11730454394646.html

NASA astronaut Suni Williams sends Happy Diwali wishes from ISS

November 1, 2024

As millions of people around the world celebrate Diwali, the Hindu festival of lights, NASA astronaut Sunita Williams radioed home a message of festive cheer.

"I want to extend my warmest wishes for a Happy Diwali to everyone celebrating the festival of lights today at the White House and around the world," Williams said in a recent video message sent from the International Space Station.

"This year, I have the unique opportunity to celebrate Diwali from 260 miles above the Earth on the ISS."

Speaking from the ISS' window-filled cupola with Earth as her backdrop, Williams, who is an American with Indian heritage, spoke about her father's efforts to keep Indian culture alive after he migrated to the United States in 1957.

She also touched upon the symbolism of Diwali — the triumph of good over evil, light over darkness and hope over despair.

"Diwali is a time of joy as goodness in the world prevails," she said.

Williams’ holiday message was played earlier this week at the White House, where President Joe Biden hosted a Diwali reception that was attended by over 600 Indian-American congresspersons and business leaders from across the nation.

"It was the chance to wish my staff happy Diwali, but it was also a chance to thank them for their service to our country," Biden said during his speech.

"Astronauts talk about that thin blue line that separates Earth from space, life from destruction, lightness from darkness," he added.

"But we thought what a wonderful way to celebrate the festival of lights at the White House, by looking up into the heavens, to keep our heads high as we seek the spirit of Diwali — knowledge over ignorance, goodness over hate, unity over division — and to look up focused on the North Star of our nation."

Williams and fellow NASA astronaut Butch Wilmore are now scheduled to return in February 2025 in a SpaceX Crew Dragon capsule after their original ride, Boeing's Starliner, malfunctioned in space and returned to Earth empty in September.

NASA said last week it is still working on the issues even as Boeing is reportedly considering selling the vehicle, along with other aspects of its space business, due to mounting financial issues.

On Thursday (Oct. 31), the night of the new moon and the most important day of the five-day festival, people across faiths and continents outfitted their homes and places of worship with oil lamps, prayed, feasted, and set off fireworks.

In what appears to have become a custom alongside the yearly celebration, a satellite image billed to show India lit for Diwali resurfaced on social media sites for the 12th year in a row.

Multiple news organizations have debunked the image over the years, clarifying that it does come from satellite data but is a color-composite created back in 2003 by scientists intending to highlight the country's population growth over time.

NASA once chimed in with a real image of India on Diwali night, noting any extra light produced during Diwali is so subtle it's imperceptible from space — including the ISS.

https://www.space.com/space-exploration/international-space-station/nasa-astronaut-suni-williams-sends-happy-diwali-wishes-from-iss-video

Spooky Earths seen by Hera’s HyperScout

31/10/2024

This spooky-tinged multiplicity of planet Earths comes especially for Halloween, as observed through the various spectral bands of the Hera asteroid mission’s HyperScout H instrument out in deep space.

Hera’s HyperScout H is a hyperspectral imager that observes its targets in more colours than the human eye can distinguish, across 25 spectral bands from the visible to near infrared 650–950 nm wavelength spectral range.

These close-up images of Earth were produced by separating these wavelengths to show how the instrument operates in practice, as observed on 11 October 11 between 01:59 to 18:09 UTC.

The false colour images are visualised using the TwilightShifted palette: a colour map ranging across bluish black through purplish white into reddish black to represent light intensity levels.

“This allows us to observe cloud patterns on our planet from a distance of nearly 2 000 000 km away and to test the sharpness of our data processing algorithms,” says instrument team member Marcel Popescu of the University of Craiova in Romania.

“To quote Carl Sagan, all our lives are contained within these few pixels.”

Following a successful launch on 7 October 2024, Hera’s instruments were switched on for the first time as part of the spacecraft’s ongoing Near-Earth Commissioning Phase.

On Thursday 10 October and Friday 11 October, Hera’s topside Asteroid Deck, which houses the spacecraft’s instruments, was pointed back towards our planet so that its instruments could capture their first images of Earth and the Moon from a distance of more than one million km away.

“Once Hera reaches the Dimorphos asteroid HyperScout H will prospect its mineral make-up,” explains instrument principal investigator Julia de León of Instituto de Astrofísica de Canarias.

“This first calibration test was an exciting experience, which showed that both the instrument and its data processing chain are working well.”

The shoebox-sized HyperScout H is the latest in a family of HyperScout imagers previously flown in terrestrial orbit for Earth observation, produced by cosine Remote Sensing in the Netherlands with ESA support.

Next March HyperScout H will also be among the Hera instruments trained on Mars and martian moon Deimos as the mission performs a swingby of the red planet.

Marco Esposito, cosine Remote Sensing’s Managing Director, comments: “It is fantastic to have the Earth-Moon system as our first target, observing this unique relationship and capturing it spectrally as we move swiftly toward Mars.”

https://www.esa.int/ESA_Multimedia/Images/2024/10/Spooky_Earths_seen_by_Hera_s_HyperScout