Nancy has been with Universe Today since 2004, and has published over 6,000 articles on space exploration, astronomy, science and technology. She is the author of two books: "Eight Years to the Moon: the History of the Apollo Missions," (2019) which shares the stories of 60 engineers and scientists who worked behind the scenes to make landing on the Moon possible; and "Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos" (2016) tells the stories of those who work on NASA's robotic missions to explore the Solar System and beyond.
Follow Nancy on Twitter at https://twitter.com/Nancy_A and and Instagram at and https://www.instagram.com/nancyatkinson_ut/
The Parkes radio telescope, one of the telescopes comprising CSIRO’s Australia Telescope National Facility. Credit: CSIRO
This year’s International Astronautical Congress is being held in Adelaide, Australia and the opening ceremonies of this meeting of ‘all things space’ included a special announcement. The Australian government announced that it will establish a new national space agency, with the hopes of growing Australia’s already vibrant space industry.
Michaelia Cash, Australian’s acting Minister of Industry, Innovation and Science was quoted as saying that Australia will not have a NASA but an agency “right for our nation, right for our industry … that will provide the vehicle for Australia to have a long-term strategic plan for space – a plan that supports the innovative application of space technologies and grows our domestic space industry, including through defense space procurement.”
Australia’s space industry is worth about $4 billion and already employs about 11,500 people. But proponents for creating a space agency for the country say it will help coordinate and expand the efforts.
Of course Australia has been very active in space exploration, being part of every deep-space mission NASA has flown with tracking and communications as part the Deep Space Network and the precursor system of dishes around the world. The tracking and communications dish at Parkes, Honeysuckle Creek, Tidbinbilla and Canberra were notoriously part of the Apollo missions, and several other large radio dishes in Australia have been listening to space to tease out astronomical details. Additionally, the Square Kilometer Array being built in Australia, New Zealand and South Africa will help us answer fundamental questions in astronomy and cosmology.
But still, many have said that Australia is one of the few major developed countries that do not have a space agency. New Zealand established their space agency last year. You can see a list of all the world’s space agencies from Heather Archuletta’s Pillownaut website.
Reportedly, the plan is to double the size of Australia’s current space capacity within five years and add thousands of new jobs, while taking advantage of new technology such as cubesats.
“We have longstanding ties with NASA, exploring space together and generating all of these jobs. And that’s the key point, it is a jobs industry-first agency,” astrophysicist Alan Duffy told ABC. “It’s designed to create satellites and new uses for the images that come from those satellites, and I don’t mean giant, bus-sized satellites of the ‘60s and ‘70s. Thanks to smartphones something the size of a toaster has the same capabilities as some of these historic launches. So we get to space cheaper and we can do more when we’re there.”
Reportedly, more details of the new space agency will be announced this week during the IAC, which is a gathering of thousands of global space experts, heads of other space agencies and private companies.
Artist concept of Cassini's last moments at Saturn. Credit: NASA/JPL.
Until the very end, Cassini displayed just how robust and enduring this spacecraft has been throughout its entire 20 years in space and its 13-year mission at Saturn. As Cassini plummeted through the ringed-planet’s atmosphere, its thrusters fought the good fight to keep the antenna pointed at Earth for as long as possible, sending as much of the last drops of science data as it could.
Cassini endured about 40 seconds longer than expected before loss of signal was called at 11:55:46 UTC
“I hope you’re all deeply proud of this accomplishment,” said Cassini Project Manager Earl Maize in JPL’s Mission Control Center after Cassini’s signal was lost. “This has been an incredible mission, and incredible spacecraft and an incredible team. I’m going to call this the end of mission. Project Manager off the net.”
Of course, the actual demise of Cassini took place about an hour and 23 minutes before, as it took that long for the signal to travel the 1.5 billion km distance from Saturn to Earth.
“This is a bittersweet moment for all of us,” said JPL Director Mike Watkins, “but I think it is more sweet than bitter because Cassini has been such an incredible mission. This is a great time to celebrate the hard work and dedication of those who have worked on this mission.”
Watkins added that almost everything we know about Saturn comes from the Cassini mission. “It made discoveries so compelling that we have to back,” he said. “We will go back and fly through the geysers of Encleadus and we’ll go back to explore Titan… These are incredibly compelling targets.”
Cassini program manager at JPL, Earl Maize, left, and spacecraft operations team manager for the Cassini mission at Saturn, Julie Webster, right, embrace after the Cassini spacecraft plunged into Saturn, Friday, Sept. 15, 2017 at NASA’s Jet Propulsion Laboratory in Pasadena, California. Photo Credit: (NASA/Joel Kowsky)
Our spacecraft has entered Saturn’s atmosphere, and we have received its final transmission.
Cassini launched on Oct. 15, 1997, and arrived at Saturn’s in 2004. It studied Saturn’s rings and sent back postcards almost every day of its journeys around the Saturn system, pictures of complex moons, the intriguing rings and the giant gas planet.
It revealed the moon Enceladus as one of the most geothermally active places in our solar system, showing it to be one of the prime targets in the search for life beyond Earth.
Saturn’s active, ocean-bearing moon Enceladus sinks behind the giant planet in a farewell portrait from NASA’s Cassini spacecraft. Credits: NASA/JPL-Caltech/Space Science Institute
Also, piggybacking along was the Huygens probe to study Saturn’s largest moon, Titan. This landing in 2005 was the first spacecraft to land in the outer solar system.
During its final plunge, Cassini’s instruments captured data on Saturn’s atmosphere, sending a strong signal throughout. As planned, data from eight of Cassini’s science instruments will be providing new insights about Saturn, including hints about the planet’s formation and evolution, and processes occurring in its atmosphere.
This death plunge ensures Saturn’s moons will remain pristine for future exploration.
Over 260 scientists from 17 countries and hundreds of engineers worked with Cassini throughout the entire mission. During Cassini’s final days, mission team members from all around the world gathered at JPL to celebrate the achievements of this historic mission.
Here is the last picture taken by Cassini’s cameras, showing the place where Cassini likely met its demise:
This monochrome view is the last image taken by the imaging cameras on NASA’s Cassini spacecraft. It looks toward the planet’s night side, lit by reflected light from the rings, and shows the location at which the spacecraft would enter the planet’s atmosphere hours later. Credit: NASA/JPL-Caltech/Space Science Institute
Artist rendition of the Cassini spacecraft over Saturn. Credit: NASA/JPL-Caltech/SSI/Kevin M. Gill.
“With Cassini, we had a rare opportunity and we seized it,” said Linda Spilker, Cassini Mission Scientist.
And on Friday, September 15, we say goodbye to this incredible spacecraft.
Since 2004, Cassini has been orbiting Saturn, exploring the magnificent gas giant planet while weaving through an incredibly diverse assortment of 60-plus icy moons, and skimming along the edges of the complex but iconic icy rings.
Cassini’s findings have revolutionized our understanding of the entire Saturn system, providing intriguing insights on Saturn itself as well as revealing secrets held by moons such as Enceladus, which should be a big iceball but instead is one of the most geothermally active places in our solar system. And thanks to the Huygens lander, we now know Saturn’s largest moon, Titan is eerily Earthlike, but yet totally alien.
“The lasting story of Cassini will likely be its longevity and the monumental amount of scientific discovery,” Cassini Project Manager Earl Maize told me last year. “It was absolutely the right spacecraft in the right place at the right time to capture a huge array of phenomena at Saturn.”
But after 20 years in space, the Cassini spacecraft is running out of fuel, and so Cassini will conduct a sacred act known as ‘planetary protection.’ This self-sacrifice will ensure any potentially habitable moons of Saturn won’t be contaminated sometime in the future if the drifting, unpowered spacecraft were to accidentally crash land there. Microbes from Earth might still be adhering to Cassini, and its RTG power source still generates warmth. It could melt through the icy crust of one of Saturn’s moons, possibly, and reach a subsurface ocean.
Diagram of Cassini’s final week, showing some of the milestones as the spacecraft heads for its plunge into Saturn. Credit: NASA/JPL-Caltech
For a mission this big, this long and this unprecedented, it will end in spectacular fashion. Called the Grand Finale — which actually began last spring — Cassini has made 22 close passes through the small gap between Saturn’s cloud tops and the innermost ring. This series of orbits has sent the spacecraft on an inevitable path towards destruction.
And tomorrow, on its final orbit, Cassini will plunge into Saturn’s atmosphere at tens of thousands of kilometers per hour. Like the science-churning machine it has been throughout its mission, Cassini will continue to conduct science observations until the very end, sending back long-sought after data about Saturn’s atmosphere. But eventually, the spacecraft will be utterly destroyed by the gas planet’s heat and pressure. It will burn up like a meteor, and become part of the planet itself.
There’s no real way to sum up this amazing mission in one article, and so I’ll leave some links and information below for you to peruse.
But I’ll also leave you with this: Instead of feeling like the mission is over, I prefer to think of Cassini as living forever, because of all the data it provided that has yet to be studied. Linda Spilker told me this last year:
“In one way,” Spilker said, “the mission will end. But we have collected this treasure trove of data, so we have decades of additional work ahead of us. With this firehose of data coming back basically every day, we have only been able to skim the cream off the top of the best images and data. But imagine how many new discoveries we haven’t made yet! The search for a more complete understanding of the Saturn system continues, and we leave that legacy to those who come after, as we dream of future missions to continue the exploration we began.”
But if you want to say goodbye to Cassini, scientist Sarah Hörst might have suggested the best way to do it:
Maybe step outside in the dark before Fri morning, find Saturn and take a moment to say hello and goodbye to @CassiniSaturn one final time
Imaging wizard Kevin Gill has put together a “Visions of Cassini” video with a great compilation of images from the mission. Here’s a shorter two minute version:
Or a longer, two and a half hour version!
These are one of the highest-resolution color images of any part of Saturn’s rings, taken on taken on July 6, 2017, with the Cassini spacecraft narrow-angle camera. This image shows a portion of the inner-central part of the planet’s B Ring. Credit: NASA/JPL-Caltech/Space Science Institute
The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime view of the Category 5 Hurricane Irma in the early hours of September 5, 2017. When the image was acquired, the storm’s center was moving due west. A National Hurricane Center forecast called for the hurricane to turn west-northwest toward the northern Leeward Islands. Credit: NASA, NOAA, Suomi NPP - VIIRS.
Record-setting Hurricane Irma barreled over the Caribbean islands of St. Martin, St. Barthelemy and Anguilla early Wednesday, destroying buildings with its sustained winds of 185 mph (297 kph), with rains and storm surges causing major flooding. The US National Hurricane Center listed the Category 5 Irma as the strongest Atlantic hurricane ever recorded north of the Caribbean and east of the Gulf of Mexico. The storm continues to roar on a path toward the U.S. and British Virgin Islands, Puerto Rico and possibly Florida, or along the southeast coast of the US.
This animation of NOAA’s GOES East satellite imagery from Sept. 3 at 8:15 a.m. EDT (1215 UTC) to Sept. 6 ending at 8:15 a.m. EDT (1215 UTC) shows Category 5 Hurricane Irma as it moved west and track over St. Martin by 8 a.m. EDT on Sept. 6:
Different models have Irma traveling on slightly different paths and officials from all the areas that might possibly be hit are telling people to prepare and follow evacuation orders. National Hurricane Center scientist Eric Blake said via twitter that some models had the storm going one way, and some another. But he cautioned everyone in a potential path should take precautions. “Model trends can be quite misleading- could just change right back. It is all probabilistic at this point. It could still miss [one particular area]. But chances of an extreme event is rising.”
The fleet of Earth-observing satellites are providing incredible views of this monster storm, and even astronauts on board the International Space Station are capturing views:
The International Space Station’s external cameras captured a dramatic view of Hurricane Irma as it moved across the Atlantic Ocean Sept. 5. pic.twitter.com/mc61pt2G8O
GOES-16 view of #HurricaneIrma at 30-second intervals covering 5-hour period ending at 352 AM CDT (9/6), including its passage over Barbuda. pic.twitter.com/WL6l6klPKw
While satellite views provide the most comprehensive view of Irma’s potential track, there’s also a more ‘hands-on’ approach to getting data on hurricanes. NOAA hurricane hunter Nick Underwood posted this video while his plane flew into Hurricane Irma yesterday. The plane’s specialized instruments can take readings on the storm that forecasters can’t get anywhere else:
In the meantime, a launch is scheduled from Cape Canaveral on Thursday, September 7. SpaceX is hoping to launch the US Air Force’s X-37B reusable spaceplane, but current forecasts put only a 50% chance of weather suitable enough on Thursday, and only 40% on Friday. We’ll keep you posted.
For the latest satellite views, the Twitter accounts above are posting regular updates.
On Sept. 4 at 17:24 UTC, NASA-NOAA’s Suomi NPP satellite captured this view of Hurricane Irma as a Category 4 hurricane approaching the Leeward Islands. Credits: NOAA/NASA Goddard MODIS Rapid Response Team.
Elon Musk shared a photo on Instagram of SpaceX's spacesuit design. Credit: Elon Musk.
SpaceX CEO and founder Elon Musk made public the first official photo of the commercial space company’s spacesuit design with a post on Instagram today. He indicated he’ll have more details soon and said this first ‘reveal’ isn’t just a prototype design; it’s a real, working spacesuit.
“Worth noting that this actually works (not a mockup)” Musk said. “Already tested to double vacuum pressure.”
The person inside the suit – in what looks to be a computer generated photo – looks much like Musk himself, although the face is rather hard to make out.
Following the design of many previous spacesuits, it comes in white. Musk said in designing the suit, it was “incredibly hard to balance esthetics and function. Easy to do either separately.”
There has been some discussion on social media about the orientation of the flag, as it appears to many to be “backward.” However, this follows US military custom of flags on uniforms, positioned on the right shoulder in this same orientation, with stars facing forward. This gives the effect of the flag “flying in the breeze” as the person in the uniform/spacesuit moves forward.
These are the spacesuits that will be worn by the astronauts who make the first flights on the Dragon Capsule to the International Space Station as part of the commercial crew program. The target for the first humans aboard Dragon is next year, mid-2018.
If you are looking for a spacesuit that has a little more pop of color — as well as a heart-felt mission — NASA also held a special news conference from the International Space Station today revealing a colorful new spacesuit created by children around the world who are suffering from cancer.
Touched…what an inspiring project @spacesuitart is.These children are such an amazing example of the strength of humanity working together pic.twitter.com/6HfucuWoJc
The Space Suit Art Project is a collaboration between NASA, spacesuit maker ILC Dover and children in hospitals around the world. This suit, called Unity, is the third in a series of suits. The suits are made of colorful patches made by young cancer patients, giving the kids an opportunity to be part of a lasting and out-of-this-world project.
Astronaut Jack Fischer donned the special (non-functioning) spacesuit and said it was tricky to get into, just like a real spacesuit. But this suit, Fischer said, “gives you the honor to represent the bravest kids in the world, who put it together.” Fischer’s daughter Bethany, is a cancer survivor.
Totality of the August 21, 2017 solar eclipse, as seen from Waterloo, Illinois. Credit and copyright: Rob Sparks.
Holy moly, that was awesome! Incredible, fantastic, amazing…there just aren’t the words to describe what it is like to experience totality. While I’m trying to come down to Earth and figure out how to explain how wonderful this was, enjoy the beautiful images captured by our readers from across the US and those from across the world who traveled to capture one of nature’s most spectacular events: a total solar eclipse.
The images from those seeing partial eclipses are wonderful, as well, and we’ll keep adding them as they come in (update, we just got some from Europe too). Great job everyone!
Eclipse panorama. Got some cool Baily’s Beads and that prominence is nuts! Shot at 2000mm on an old Celestron 8in telescope! Credit and copyright: Kenneth Brandon.2017 Solar Eclipse from Clayton GA, USA. Celestron C8 Telescope on CGEM. Canon T3i (Modified IR enhanced), Solar Filter. Credit and copyright: Michael Bee.The August 21, 2017 total solar eclipse over the Grand Tetons as seen from the Teton Valley in Idaho, near Driggs. ..This is from a 700-frame time-lapse and is of second contact just as the diamond ring is ending and the dark shadow of the Moon is approaching from the west at right, darkening the sky at right, and beginning to touch the Sun. The peaks of the Tetons are not yet in the umbral shadow and are still lit by the partially eclipsed Sun. ..With the Canon 6D and 14mm SP Rokinon lens at f/2.5 for 1/10 second at ISO 100. Credit and copyright: Alan Dyer.Total Solar Eclipse, August 21, 2017 as seen from Tellico Plains, Tennessee. New City Expedition, photo by Igor Kuskovsky.Total Solar Eclipse, Aug. 21, 2017, as seen from Charleston, South Carolina. Credit and copyright: Jason MajorPartial Eclipse montage from Charlottesville, Virginia. Credit and copyright: David Murr.Partial Solar Eclipse August 21st 2017, as seen from Fullerton California USA. Sky: Partially Cloudy. Telescope: Nexstar 102 SLT Refractor, Camera: Fujifilm X-T1 @ Prime Focus. Credit and copyright: Jimmy CD.From the total solar eclipse as seen in Columbia, Missouri, on Aug. 21, 2017. Credit and copyright: Wildhaven Creative.Total Eclipse from Shaw Air Force Base (August 21, 2017). It was magical. Credit and copyright: Michael Seeley.
Great American Eclipse, 21-08-2017. Silver Falls Oregon 10:17-10:19 local time. Raw straight out of the camera. 65mm Refractor / Canon 700D. Credit and copyright: Alexandra Hart.
Stars and the limb of Earth seen in the background of the International Space Station on July 29, 2017. Credit: NASA/Jack Fischer.
I’ve often been asked the question, “Can the astronauts on the Space Station see the stars?” Astronaut Jack Fischer provides an unequivocal answer of “yes!” with a recent post on Twitter of a timelapse he took from the ISS. Fischer captured the arc of the Milky Way in all its glory, saying it “paints the heavens in a thick coat of awesome-sauce!”
Can you see stars from up here? Oh yeah baby! Check out the Milky Way as it spins & paints the heavens in a thick coat of awesome-sauce! pic.twitter.com/MsXeNHPxLF
But, you might be saying, “how can this be? I thought the astronauts on the Moon couldn’t see any stars, so how can anyone see stars in space?”
John W. Young on the Moon during Apollo 16 mission. Charles M. Duke Jr. took this picture. The LM Orion is on the left. April 21, 1972. Credit: NASA
It is a common misconception that the Apollo astronauts didn’t see any stars. While stars don’t show up in the pictures from the Apollo missions, that’s because the camera exposures were set to allow for good images of the bright sunlit lunar surface, which included astronauts in bright white space suits and shiny spacecraft. Apollo astronauts reported they could see the brighter stars if they stood in the shadow of the Lunar Module, and also they saw stars while orbiting the far side of the Moon. Al Worden from Apollo 15 has said the sky was “awash with stars” in the view from the far side of the Moon that was not in daylight.
Just like stargazers on Earth need dark skies to see stars, so too when you’re in space.
The cool thing about being in the ISS is that astronauts experience nighttime 16 times a day (in 45 minute intervals) as they orbit the Earth every 90 minutes, and can have extremely dark skies when they are on the “dark” side of Earth. Here’s another recent picture from Fischer where stars can be seen:
Twinkle, twinkle, little star… Up above the world so high Like a diamond in the sky… pic.twitter.com/8H7CshyP0p
For stars to show up in any image, its all about the exposure settings. For example, if you are outside (on Earth) on a dark night and can see thousands of stars, if you just take your camera or phone camera and snap a quick picture, you’ll just get a darkness. Earth-bound astrophotographers need long-exposure shots to capture the Milky Way. Same is true with ISS astronauts: if they take long-exposure shots, they can get stunning images like this one:
This long exposure image of the night sky over Earth was taken on August 9, 2015 by a member of the Expedition 44 crew on board the International Space Station. Credit: NASA.
This image, set to capture the bright solar arrays and the rather bright Earth (even though its in twilight) reveals no stars:
Sometimes you look out the window and it just takes your breath away from how beautiful Earth is. Today is one of those times… #EarthShapespic.twitter.com/53UqL9BFH1
If you are looking forward to the August 21 solar eclipse as much as we are, you’ll want to check out a new series on CuriosityStream called “Eclipse Across America.”
The four-part series takes an inside preview at this highly anticipated event. NASA experts, an international group of astronomers and seasoned eclipse chasers reveal secret viewing spots and tips on how to safely view what could be for millions of people a once-in-a-lifetime opportunity to see one of the most spectacular sights in nature: a total solar eclipse.
Our friend and Astronomy Cast co-host Dr. Pamela Gay, who is also the Director of Technology at the Astronomical Society of the Pacific, is part of the all-star “astronomy cast” (pun intended) of experts, and she talked with us about her part in the show.
“I get to talk about the really cool parts of an eclipse, where you can experience totality and actually feel the temperature change,” she said. Using state-of-the-art special effects, Pamela gets to show off what the eclipse will likely look like at spots around her location in the St. Louis, MO area. “There’s the fickleness of it, where some buildings will see totality and another won’t,” she said. “Of course, the closer you get to the centerline the longer totality will be, and there are some beautiful locations where you can see it.”
A special effects image from CuriosityStream showing how the solar eclipse could look in St. Louis, Missouri. Credit: CuriosityStream.
The really fun part of this particular eclipse is that it takes a path across the entire continental U.S. I asked Pamela if, given the rather divisive political and social climate these days in this country, could this total solar eclipse become a possible unifying moment?
“I think that during the event there will be a lot of overwhelming experiences that people sometimes have of being in a crowd – such as will there be enough bathrooms,” she said. “But afterwards, I think it will be this shared ‘do you remember when’ moment that we’ll have for the rest of our lives. We all have certain moments that we remember and currently here in the US a lot of those memories are ‘where were you when 911 happened? Or where were you when we started bombing Iraq.’ This will be ‘where you when the sun was eclipsed,’ and that is so much better than ‘where were you when the towers fell down.’”
If you already have a CuriosityStream account, you can watch the series starting with Episode One here. If you don’t, you can take advantage of a 7-day free trial in order to watch this series, and all the other great science offerings available, such as Stephen Hawking’s Universe, Brian Cox’s Wonders of Life, and other topics from astronomy observing tips to info about various missions to theoretical physics. Check it out. If you’re interested in continuing after your free trial, the ad-free streaming service costs $2.99, $5.99 and $11.99 per month for standard definition, high definition, and ultra high definition 4K respectively.
The partial lunar eclipse on August 7, 2017 as seen from Bucharest, Romania. Credit and copyright: Loredana Jucan.
Just to get you in the mood for the upcoming total solar eclipse — now less than two weeks away — our Solar System put on a little eclipse display of the lunar kind on August 7. The full Moon passed through part of the Earth’s umbral shadow, and the timing made this partial lunar eclipse visible in parts of Europe and Africa.
Thanks to our friends around the world who posted in Universe Today’s Flickr page, we’ve got images to share! Enjoy the views! Click on all the images to see larger versions of them on Flickr. The lead image link is here.
And for those of you in the path of the August 21 solar eclipse, please feel free to share your images on our Flickr page, and we may feature them in an upcoming article.
A composite of images take during the August 2017 lunar eclipse, as see from Kuala Lumpur. Credit and copyright: Shahrin Ahmad.Partial lunar eclipse seen from Lausanne’s lakeshore in Switzerland … The Moon had just moved up from behind the Tour d’Aï Peaks. Credit and copyright: Hicham Dennaoui.Partial Eclipse of Moon over the Church of Our Lady of the Bell in Casarano, Sicily, Italy. Single photo taken with a Konus 80/400 telescope and Canon 700d camera. Credit and copyright: Gianluca Belgrado. Eclipsed full moon over the eastern horizon as seen from Treppendorf, Brandenburg, Germany. Credit and copyright: Andreas Schnabel.Partial lunar eclipse of August 7th 2017, as seen from Bavaria, Germany at around 19:17 UTC. Shot with an EOS 550D mounted to a Meade ETX 70 Telescope. Exposure was 1/125 seconds with ISO 100. Credit and copyright: Stephan Haverland. The partial lunar eclipse as see from Czolpino, Pomerania, Poland. Credit and copyright: Pawel Warchal. A view of the partial lunar eclipse on August 7, 2017 as seen from Malta in the Mediterranean Sea. Credit and copyright: Leonard Ellul-Mercer.
Here is a video of additional images from Leonard Mercer:
You can watch a reply of a live webcast from the Virtual Telescope Project of the partial lunar eclipse seen from Rome:
New Horizon's July 2015 flyby of Pluto captured this iconic image of the heart-shaped region called Tombaugh Regio. Credit:
NASA/JHUAPL/SwRI.
It was two years ago this morning that we awoke to see the now iconic image of Pluto that the New Horizons spacecraft had sent to Earth during the night. You, of course, know the picture I’m talking about – the one with a clear view of the giant heart-shaped region on the distant, little world (see above).
This image was taken just 16 hours before the spacecraft would make its closest approach to Pluto. Then, during that seemingly brief flyby (after traveling nine-and-a-half years and 3 billion miles to get there), the spacecraft gathered as much data as possible and we’ve been swooning over the images and pondering the findings from New Horizons ever since.
“This is what we came for – these images, spectra and other data types that are helping us understand the origin and the evolution of the Pluto system for the first time,” New Horizons principal investigator Alan Stern told me last year. “We’re seeing that Pluto is a scientific wonderland. The images have been just magical. It’s breathtaking.”
See a stunning new video created from flbyby footage in honor of the two-year anniversary of the flyby:
All the images have shown us that Pluto is a complex world with incredible diversity, in its geology and also in its atmosphere.
While the iconic “heart” image shows a clear and cloudless view of Pluto, a later image showed incredible detail of Pluto’s hazy atmosphere, with over two dozen concentric layers that stretches more than 200 km high in Pluto’s sky.
With all those layers and all that haze, could there be clouds on Pluto too?
The smooth expanse of the informally named Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 11,000 feet (3,500 meters) high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. The backlighting highlights more than a dozen layers of haze in Pluto’s tenuous but distended atmosphere. Credit: NASA/JHUAPL/SwRI.
This is a question Stern and his fellow scientists have been asking for a long time, actually, as they have been studying Pluto for decades from afar. Now with data from New Horizons, they’ve been able to look closer. While Stern and his colleagues have been discussing how they found possible clouds on Pluto for a few months, they have now detailed their findings in a paper published last month.
“Numerous planets in our solar system, including Venus, Earth, Mars, Titan, and all four of the giant planets possess atmospheres that contain clouds, i.e., discrete atmospheric condensation structures,” the team wrote in their paper. “This said, it has long been known that Pluto’s current atmosphere is not extensively cloudy at optical or infrared wavelengths.”
They explained that evidence for this came primarily from the “high amplitude and temporal stability of Pluto’s lightcurve,” however, because no high spatial resolution imagery of Pluto was possible before New Horizons, it remained to be seen if clouds occur over a small fraction of Pluto’s surface area.
But now with flyby images in hand, the team set out to do searches for clouds on Pluto, looking at all available imagery from the Long Range Reconnaissance Imager and the Multispectral Visible Imaging Camera, looking at both the disk of Pluto and near and on the limb. Since an automated cloud search was nearly impossible, it was all done by visual inspection of the images by the scientists.
They looked for features in the atmosphere that including brightness, fuzzy or fluffy-looking edges and isolated borders.
Seven Possible Cloud Candidates (PCCs) identified by the New Horizons team. Two of these images (3, 4) were taken by MVIC; the other five (1, 2, 5, 6, 7) were taken by LORRI. Arrows indicate each PCC. Credit: Stern et al, 2017.
In all, they found seven bright, discrete possible cloud candidates. The seven candidates share several different attributes including small size, low altitude, they all were visible either early or late in the day local time, and were only visible at oblique geometry – which is basically a sideways look from the spacecraft.
Also, several cloud candidates also coincided with brighter surface features below, so the team is still pondering the correlation.
“The seven candidates are all similar in that they are very low altitude,” Stern said last fall at the Division of Planetary Sciences meeting, “and they are all low-lying, isolated small features, so no broad cloud decks or fields. When we map them over the surface, they all lie near the terminator, so they occur near dawn or dusk. This is all suggestive they are clouds because low-lying regions and dawn or dusk provide cooler conditions where clouds may occur.”
While haze was detected as high as 220 km, the possible clouds were found at very low altitudes. Stern told Universe Today that these possible, rare condensation clouds could be made of ethane, acetylene, hydrogen cyanide or methane under the right conditions. Stern added these clouds are probably short-lived phenomena – again, likely occurring only at dawn or dusk. A day on Pluto is 6.4 days on Earth.
But all in all, they concluded that at the current time Pluto’s atmosphere is almost entirely free of clouds – in fact the dwarf planet’s sky was 99% cloud free the day that New Horizons whizzed by.
“But if there are clouds, it would mean the weather on Pluto is even more complex than we imagined,” Stern said last year.
The seven cloud candidates cannot be confirmed as clouds because none are in the region where there was stereo imaging or other available ways to cross-check it. They concluded that further modeling would be needed, but specifically a Pluto orbiter mission would be the only way to “search for clouds more thoroughly than time and space and was possible during the brief reconnaissance flyby by New Horizons.”
