NASA will make a “surprising” announcement about Jupiter’s moon Europa on Monday, Sept. 26th, at 2:00 PM EDT. They haven’t said much, other than there is “surprising evidence of activity that may be related to the presence of a subsurface ocean on Europa.” Europa is a prime target for the search for life because of its subsurface ocean.
The new evidence is from a “unique Europa observing campaign” aimed at the icy moon. The Hubble Space Telescope captured the images in these new findings, so maybe we’ll be treated to some more of the beautiful images that we’re accustomed to seeing from the Hubble.
Images from NASA’s Galileo spacecraft show the intricate detail of Europa’s icy surface. Image: NASA/JPL-Caltech/ SETI Institute
We always welcome beautiful images, of course. But the real interest in Europa lies in its suitability for harboring life. Europa has a frozen surface, but underneath that ice there is probably an ocean. The frozen surface is thought to be about 10 – 30 km thick, and the ocean may be about 100 km (62 miles) thick. That’s a lot of water, perhaps double what Earth has, and that water is probably salty.
Back in 2012, the Hubble captured evidence of plumes of water vapor escaping from Europa’s south pole. Hubble didn’t directly image the water vapor, but it “spectroscopically detected auroral emissions from oxygen and hydrogen” according to a NASA news release at the time.
This artist’s illustration shows what plumes of water vapour might look like being ejected from Europa’s south pole. Image: NASA, ESA, L. Roth (Southwest Research Institute, USA/University of Cologne, Germany) and M. Kornmesser.
There are other lines of evidence that support the existence of a sub-surface ocean on Europa. But there are a lot of questions. Will the frozen top layer be several tens of kilometres thick, or only a few hundred meters thick? Will the sub-surface ocean be warm, liquid water? Or will it be frozen too, but warmer than the surface ice and still convective?
Two models of the interior of Europa. Image: NASA/JPL.
Hopefully, new evidence from the Hubble will answer these questions definitively. Stay tuned to Monday’s teleconference to find out what NASA has to tell us.
These are the scientists who will be involved in the teleconference:
Paul Hertz, director of the Astrophysics Division at NASA Headquarters in Washington
William Sparks, astronomer with the Space Telescope Science Institute in Baltimore
Britney Schmidt, assistant professor at the School of Earth and Atmospheric Sciences at Georgia Institute of Technology in Atlanta
Jennifer Wiseman, senior Hubble project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland
The NASA website will stream audio from the teleconference.
SpaceX founder and CEO Elon Musk. Credit: Ken Kremer/kenkremer.com
For Elon Musk, it’s always been about Mars. Musk, and his company SpaceX, haven’t always been explicit about how exactly they’ll get to Mars. But SpaceX’s fourteen years of effort in rocketry have been aimed at getting people into space cheaper, and getting people to Mars.
Musk has revealed hints along the way. One of the boldest was his statement at Code Conference 2016. At that conference he said, “I think, if things go according to plan, we should be able to launch people probably in 2024, with arrival in 2025.”
He went on to explain it this way: “The basic game plan is we’re going to send a mission to Mars with every Mars opportunity from 2018 onwards. They occur approximately every 26 months. We’re establishing cargo flights to Mars that people can count on for cargo.”
Those comments certainly removed any lingering doubt that Mars is the goal.
But a recent Tweet from Musk has us wondering if Mars will just be a stepping stone to more distant destinations in our Solar System. On Sept. 16th, Musk tweeted:
Turns out MCT can go well beyond Mars, so will need a new name…
And the new name is Interplanetary Transport System (ITS).
So, is SpaceX developing plans to go beyond Mars? Is the plan to establish cargo flights to Mars still central to the whole endeavour? Does the name change from Mars Cargo Transporter (MCT) to Interplanetary Transport System (ITS) signal a change in focus? These questions may be answered soon, on September 27th, when Musk will speak at the International Astronautical Congress (IAC), in Guadalajara, Mexico.
Musk hinted back in January that he would be revealing some major details of the MCT at the IAC later this month. In January, he said at the StartmeupHK Festival in Hong Kong that “I’m hoping to describe that architecture later this year at IAC … and I think that will be quite exciting.”
So, lots of hints. And these hints bring questions. Is SpaceX developing a super heavy rocket of some type? A BFR? If the Mars Colonial Transport system can go much further than Mars, maybe to the moons of the gas giants, won’t that require a much larger rocket than the Falcon Heavy?
In the past, SpaceX has conceptualized about larger rockets and the engines that would power them. At the 2010 American Institute of Aeronautics and Astronautics (AIAA) Joint Propulsion Conference, SpaceX presented some of these conceptual designs. They featured a super-heavy lift vehicle larger than the Falcon Heavy, dubbed the Falcon X. Beyond that, and in increasingly powerful designs, were the Falcon X Heavy, and the Falcon XX Heavy.
These were only concepts, but it’s six years later now. Surely, any further thinking around a super-heavy lift vehicle would have started there. And if the MCT can now go well beyond Mars, as Musk said in his Tweet, there must be a more powerful rocket. Mustn’t there?
So with one tweet, Musk has sucked the air out of the room, and got everybody speculating. But Musk isn’t the only one with eyes on building a greater human presence in space. He has a competitor: Jeff Bezos, former Amazon CEO, and his company Blue Origin.
The New Shepard reusable rocket is Blue Origin’s flagship. Image: Blue Origin
The original space race pitted the USA against the USSR in a battle for scientific supremacy and prestige. The USA won that race, and they’re still reaping the benefits of that technological victory. But a new race might be brewing between Musk and Bezos, between SpaceX and Blue Origin.
The two companies haven’t been directly competing. They’ve both been working on reusable rockets, but Blue Origin has concerned itself with sub-orbital rocketry designed to take people into space for a few minutes. Space tourism, if you will. SpaceX’s focus has always been on orbital capability, and more.
But not to be outdone by SpaceX, Blue Origin has recently announced the New Glenn orbital launch vehicle, to be powered by seven of their new, powerful, BE-4 engines.
In rocketry, size definitely matters. Image: Blue Origin
There’s definitely some one-upmanship going on between Musk and Bezos. So far, it’s mostly been civil, with each acknowledging each other’s achievements and milestones in rocketry. But they’re also both quick to point out why they’re better than the other.
Bezos, with the announcement of the New Glenn orbital launch vehicle, and the BE-4 engines that will power it, took every opportunity to mention the fact that his company spends zero tax dollars, while SpaceX benefits from financial arrangements with NASA. Musk, on the other hand, likes to point out the fact that Blue Origin has never delivered anything into orbit, while SpaceX has delivered numerous payloads into orbit successfully.
But for now, anyway, the focus is on SpaceX, and what Musk will reveal at the upcoming IAC Congress. If he reveals a solid plan for recurring cargo missions to Mars, the excitement will be palpable. And if he reveals plans to go further than Mars, with much larger rockets, we may never catch our breaths.
Israel's Shavit 2 (Comet) rocket carried the Ofek-11 (Horizon) satellite into orbit on Sept. 13, 2016. Israeli media report that the satellite is malfunctioning. Image: Israeli Ministry of Defence.
Israel launched a Shavit2 rocket from its facility at Palmachim airbase on Sept. 13. The launch was the 10th one for the Shavit rocket system, which had its initial launch in 1988. The launch and delivery were successful, but Israeli media is reporting that the payload, the Ofek-11 satellite, is malfunctioning.
The Ofek-11 satellite in Tuesday’s launch is an optical imaging satellite, basically a spy satellite, operated by the Isreali Ministry of Defence. It operates at an altitude of 600 km. It’s orbital path is designed to pass over Israel’s region 6 times per day, allowing the Ministry of Defence to focus on targets of interest in their nation’s region.
Officials involved with the launch have successfully contacted the satellite. Amnon Harari, head of the Defence Ministry’s Space Department, told the Times of Israel that it was “not clear that everything was in order,” hours after the launch.
Doron Ofer is CEO of the Israel Aerospace Industries’ Space Division, the company that makes the Shavit rocket. He told the Times of Israel that due to the satellite’s path, and the rotation of the Earth, the satellite can only be contacted a few times per day. This complicates efforts to correct the satellite.
“We have downloaded some figures, and we are now checking them. It’s not functioning exactly the way we expected, and we don’t know what it’s status is,” Ofer said. “We are now working to stabilize it, but it will take some time because of the small amount of communication we have with it when it comes in our area.”
The Ofek-11 will be the 11th satellite that provides intelligence to the Israeli forces, but not much is known about its exact capabilities. For obvious reasons, the Israeli Defence Ministry is keeping things secret.
It is widely believed that this newest satellite is among the world’s most advanced satellite recon systems. It’s enhanced imaging system purportedly collects images at a ground resolution of 0.5 meters from its 600-Kilometer orbit.
The Ofek-11 surpasses its predecessor, Ofek-9, launched in 2010, which had only a 0.7 meter resolution. The Ofek-10 was a radar imaging satellite launched in 2014 to capture all-weather, day and night images at a resolution less than 1 meter. The overlapping nature of Israel’s satellite system eliminates any gaps in their ability to monitor their region.
Two weeks ago, Israel had another failure in its satellite efforts, though that one was much more catastrophic. The Amos-6 civilian communications satellite was going to be Israel’s largest satellite to date. However, the SpaceX rocket tasked with taking Amos-6 into orbit exploded on its Cape Canaveral launch pad.
Israel is the 8th country in the world to develop their own orbital launch capabilities. They launched their first satellite, the Ofek-1, aboard the maiden flight of their Shavit-1 rocket in 1988. Including that first launch, Israel has attempted 10 launches, and has been successful 8 times. All of those have been Ofek satellites, operated by the military.
All but one of Israel’s Ofek satellites have been launched by Israel’s Shavit-1 and Shavit-2 rockets. The lone exception is Ofek-8, also known as TecSar, launched aboard the Indian Polar Satellite Launch Vehicle (PSLV).
An image of the circum-stellar disk around HD 207129. The three circled objects are background objects and are not part of the disk. Image: Hubble Space Telescope, Glenn Schneider et al 2016.
A team using the Hubble Space Telescope has imaged circumstellar disk structures (CDSs) around three stars similar to our Sun. The stars are all G-type solar analogs, and the disks themselves share similarities with our Solar System’s own Kuiper Belt. Studying these CDSs will help us better understand their ring-like structure, and the formation of solar systems.
The team behind the study was led by Glenn Schneider of the Seward Observatory at the University of Arizona. They used the Hubble’s Space Telescope Imaging Spectrograph to capture the images. The stars in the study are HD 207917, HD 207129, and HD 202628.
Theoretical models of circumstellar disk dynamics suggest the presence of CDSs. Direct observation confirms their presence, though not many of these disks are within observational range. These new deep images of three solar analog CDSs are important. Studying the structure of these rings should lead to a better understanding of the formation of solar systems themselves.
A is the observed image of HD 207917. B is the best-fit debris ring model of the same star. Image: Hubble, G. Schneider et. al. 2016.
Debris disks like these are separate from protoplanetary disks. Protoplanetary disks are a mixture of both gas and dust which exist around younger stars. They are the source material out of which planetesimals form. Those planetesimals then become planets.
Protoplanetary disks are much shorter-lived than CDSs. Whatever material is left over after planet formation is typically expelled from the host solar system by the star’s radiation pressure.
In circumstellar debris disks like the ones imaged in this study, the solar system is older, and the planets have already formed. CDSs like these have lasted this long by replenishing themselves. Collisions between larger bodies in the solar system create more debris. The resulting debris is continually ground down to smaller sizes by repeated collisions.
This process requires gravitational perturbation, either from planets in the system, or by binary stars. In fact, the presence of a CDSs is a strong hint that the solar system contains terrestrial planets.
A circumstellar disk of debris around a mature stellar system could indicate the presence of Earth-like planets. Credit: NASA/JPL
The three disks in this study were viewed at intermediate inclinations. They scatter starlight, and are more easily observed than edge-on disks. Each of the three circumstellar disk structures possess “ring-like components that are more massive analogs of our solar system’s Edgeworth–Kuiper Belt,” according to the study.
The study authors expect that the images of these three disk structures will be studied in more detail, both by themselves and by others in future research. They also say that the James Webb Space Telescope will be a powerful tool for examining CDSs.
The Milky Way is like NGC 4594 (pictured), a disc shaped spiral galaxy with around 200 billion stars. The three main features are the central bulge, the disk, and the halo. Credit: ESO
Maybe we take our beloved Milky Way galaxy for granted. As far as humanity is concerned, it’s always been here. But how did it form? What is its history?
Our Milky Way galaxy has three recognized stellar components. They are the central bulge, the disk , and the halo. How these three were formed and how they evolved are prominent, fundamental questions in astronomy. Now, a team of researchers have used the unique property of a certain type of star to help answer these fundamental questions.
The type of star in question is called the blue horizontal-branch star (BHB star), and it produces different colors depending on its age. It’s the only type of star to do that. The researchers, from the University of Notre Dame, used this property of BHB’s to create a detailed chronographic (time) map of the Milky Way’s formation.
This map has confirmed what theories and models have predicted for some time: the Milky Way galaxy formed through mergers and accretions of small haloes of gas and dust. Furthermore, the oldest stars in our galaxy are at the center, and younger stars and galaxies joined the Milky Way over billions of years, drawn in by the galaxy’s growing gravitational pull.
The team who produced this study includes astrophysicist Daniela Carollo, research assistant professor in the Department of Physics at the University of Notre Dame, and Timothy Beers, Notre Dame Chair of Astrophysics. Research assistant professor Vinicius Placco, and other colleagues rounded out the team.
“We haven’t previously known much about the age of the most ancient component of the Milky Way, which is the Halo System,” Carollo said. “But now we have demonstrated conclusively for the first time that ancient stars are in the center of the galaxy and the younger stars are found at longer distances. This is another piece of information that we can use to understand the assembly process of the galaxy, and how galaxies in general formed.”
This dazzling infrared image from NASA’s Spitzer Space Telescope shows hundreds of thousands of stars crowded into the swirling core of our spiral Milky Way galaxy. Credit: NASA/JPL-Caltech
The Sloan Digital Sky Survey (SDSS) played a key role in these findings. The team used data from the SDSS to identify over 130,000 BHB’s. Since these stars literally “show their age”, mapping them throughout the Milky Way produced a chronographic map which clearly shows the oldest stars near the center of the galaxy, and youngest stars further away.
“The colors, when the stars are at that stage of their evolution, are directly related to the amount of time that star has been alive, so we can estimate the age,” Beers said. “Once you have a map, then you can determine which stars came in first and the ages of those portions of the galaxy. We can now actually visualize how our galaxy was built up and inspect the stellar debris from some of the other small galaxies being destroyed by their interaction with ours during its assembly.”
Astronomers infer, from various data-driven approaches, that different structural parts of the galaxy have different ages. They’ve assigned ages to different parts of the galaxy, like the bulge. That makes sense, since everything can’t be the same age. Not in a galaxy that’s this old. But this map makes it even clearer.
As the authors say in their paper, “What has been missing, until only recently, is the ability to assign ages to individual stellar populations, so that the full chemo-dynamical history of the Milky Way can be assessed.”
This new map, with over 130,000 stars as data points, is a pretty important step in understanding the evolution of the Milky Way. It takes something that was based more on models and theory, however sound they were, and reinforces it with more constrained data.
Update: The chronographic map, as well as a .gif, can be viewed here.
Freddie Mercury on stage in 1977. Image: By FreddieMercurySinging21978.jpg: Carl Lender derivative work: Lošmi - FreddieMercurySinging21978.jpg, CC BY-SA 3.0
Freddie Mercury, the frontman from the rock band Queen, is getting his name etched in the night sky. No, they’re not naming another planet after him. That would be confusing. Instead, an asteroid will bear the name of the iconic singer.
If you don’t know much about the band Queen, there’s a connection between them and astronomy. Brian May, the band’s guitarist, holds a PhD. in astrophysics. He studied reflected light from interplanetary dust and the velocity of dust in the plane of the Solar System. But when Queen became mega-popular in the 70’s, he abandoned astrophysics, for the most part.
Brian May is still involved with space, and has an interest in asteroids. He helped the ESA launch Asteroid Day in June 2016, to raise awareness of the threat that asteroids pose to Earth. So there’s the connection.
As for the asteroid that will bear Freddie Mercury’s name, it was previously named Asteroid 17473, but will now be known as Asteroid FreddieMercury 17473. It’s a rock about 3.5 km in diameter in the asteroid belt between Mars and Jupiter.
Today would have been Freddie’s 70th birthday, if he were still alive. So this naming is a fitting commemorative gesture. According to the International Astronomical Union, who handles the naming of objects in space, the naming of the asteroid is in honour of “Freddie’s outstanding influence in the world.”
Brian May explains things in this video:
We’re mostly science-minded people, so you may be skeptical of Freddie’s influence in the world. He was no scientist, that’s for sure. But if you lived through Queen’s heyday, as I did, you can sort of see it.
Freddie Mercury was a very polished entertainer, with a great voice and fantastic stage presence. He mastered the theatrical side of performing as a rock frontman, and his voice spanned four octaves. The music he made with his band-members in Queen was very original. Mercury was a creative force, that’s for sure.
Check out “Killer Queen” from 1974.
Plus, William Shatner (aka Captain James Tiberius Kirk) clearly had a warm spot in his heart for Freddie and the rest of Queen. How else to explain his version of Queen’s timeless tune “Bohemian Rhapsody?”
If that isn’t a ringing endorsement of Freddie Mercury and Queen, I don’t know what is.
The asteroid that will bear Freddie Mercury’s name was discovered by Belgian astronomer Henri Debehogne in 1991. It travels an elliptical path around the Sun, and never comes closer than 350 million km to Earth. It isn’t very reflective, so only powerful telescopes can see it. But there it’ll be, for anyone with a powerful enough telescope to look with, as long as human civilization lasts.
Freddie Mercury isn’t the first entertainer to have something in space bear his name. In fact, he’s not even the first member of Queen to have that honor. An asteroid first seen in 1998 now bears the name Asteroid 52665 Brianmay, in honor of the guitarist from Queen.
Other musicians and singers who’ve had space rocks named after them include the Beatles, Enya, Frank Zappa, David Bowie, Aretha Franklin, Yes, and Bruce Springsteen. Authors Kurt Vonnegut, Vladimir Nabokov, and Douglas Adams and the characters Don Quixote, James Bond, Sherlock Holmes and Dr Watson also have the honor.
As for the rock itself, Oxford astrophysics professor Chris Lintott told the Guardian, “I think it’s wonderful to name an asteroid after Freddie Mercury. Pleasingly, it’s on a slightly eccentric orbit about the sun, just as the man himself was.”
Freddie died in 1991 from complications from AIDS, but his music still lives on. Maybe Asteroid FreddieMercury 17473 will help us remember him.
JunoCam captured this image of Jupiter's north pole region from a distance of 78,000 km (48,000 miles) above the planet.
Juno is sending data from Jupiter back to us, courtesy of the Deep Space Network, and the first images are meeting our hyped-up expectations. On August 27, the Juno spacecraft came within about 4,200 km. (2,500 miles) of Jupiter’s cloud tops. All of Juno’s instruments were active, and along with some high-quality images in visual and infrared, Juno also captured the sound that Jupiter produces.
Juno has captured the first images of Jupiter’s north pole. Beyond their interest as pure, unprecedented eye candy, the images of the pole reveal things never before seen. They show storm activity and weather patterns that are seen nowhere else in our solar system. Even on the other gas giants.
“…like nothing we have seen or imagined before.”
“First glimpse of Jupiter’s north pole, and it looks like nothing we have seen or imagined before,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. “It’s bluer in color up there than other parts of the planet, and there are a lot of storms. There is no sign of the latitudinal bands or zone and belts that we are used to — this image is hardly recognizable as Jupiter. We’re seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features.”
The iconic storm bands of Jupiter are absent in this JunoCam image of Jupiter’s northern polar region. Instead, the region is dominated by swirling storm patterns reminiscent of hurricanes here on Earth. Image: NASA/JPL-Caltech/SwRI/MSSS
The visible light images of Jupiter’s north pole are very different from our usual perception of Jupiter. People have been looking at Jupiter for a long time, and the gas giant’s storm bands, and the Great Red Spot, are iconic. But the north polar region looks completely different, with whirling, rotating storms similar to hurricanes here on Earth.
The Junocam instrument is responsible for the visible light pictures of Jupiter that we all enjoy. But the Jovian Infrared Auroral Mapper (JIRAM) is showing us a side of Jupiter that the naked eye will never see.
The Juno Infrared Auroral Mapper (JIRAM) captured this infrared image of Jupiter’s south pole. This part of Jupiter cannot be seen from Earth. Image: NASA/JPL-Caltech/SwRI/MSSS
“JIRAM is getting under Jupiter’s skin, giving us our first infrared close-ups of the planet,” said Alberto Adriani, JIRAM co-investigator from Istituto di Astrofisica e Planetologia Spaziali, Rome. “These first infrared views of Jupiter’s north and south poles are revealing warm and hot spots that have never been seen before. And while we knew that the first-ever infrared views of Jupiter’s south pole could reveal the planet’s southern aurora, we were amazed to see it for the first time.”
“No other instruments, both from Earth or space, have been able to see the southern aurora.”
Even when we’re prepared to be amazed by what Juno and other spacecraft show us, we are still amazed. It’s impossible to see Jupiter’s south pole from Earth, so these are everybody’s first glimpses of it.
“No other instruments, both from Earth or space, have been able to see the southern aurora,” said Adriani. “Now, with JIRAM, we see that it appears to be very bright and well-structured. The high level of detail in the images will tell us more about the aurora’s morphology and dynamics.”
Beyond the juicy images of Jupiter are some sound recordings. It’s been known since about the 1950’s that Jupiter is a noisy planet. Now Juno’s Radio/Plasma Wave Experiment (WAVE) has captured a recording of that sound.
“Jupiter is talking to us in a way only gas-giant worlds can,” said Bill Kurth, co-investigator for the Waves instrument from the University of Iowa, Iowa City. “Waves detected the signature emissions of the energetic particles that generate the massive auroras which encircle Jupiter’s north pole. These emissions are the strongest in the solar system. Now we are going to try to figure out where the electrons come from that are generating them.”
Oddly enough, that’s pretty much exactly what I expected Jupiter to sound like. Like something from an early sci-fi film.
There’s much more to come from Juno. These images and recordings of Jupiter are just the result of Juno’s first orbit. There are over 30 more orbits to come, as Juno examines the gas giant as it orbits beneath it.
NASA's new app, the Globe Observer, will allow users to collect observations of clouds, and engage in a little citizen science. Image: NASA GLOBE Observer
It’s long been humanity’s dream to do something useful with our smartphones. Sure, we can take selfies, and post pictures of our meals, but true smartphone greatness has eluded us. Until now, that is.
Thanks to NASA, we can now do some citizen science with our ubiquitous devices.
For over 20 years, and in schools in over 110 countries, NASA’s Global Learning and Observations to Benefit the Environment (GLOBE) program has helped students understand their local environment in a global context. Now NASA has released the GLOBE Observer app, which allows users to capture images of clouds in their local environment, and share them with scientists studying the Earth’s climate.
“With the launch of GLOBE Observer, the GLOBE program is expanding beyond the classroom to invite everyone to become a citizen Earth scientist,” said Holli Riebeek Kohl, NASA lead of GLOBE Observer. The app will initially be used to capture cloud observations and images because they’re such an important part of the global climate system. But eventually, GLOBE Observer will also be used to observe land cover, and to identify types of mosquito larvae.
GLOBE has two purposes. One is to collect solid scientific data, the other is to increase users’ awareness of their own environments. “Once you collect environmental observations with the app, they are sent to the GLOBE data and information system for use by scientists and students studying the Earth,” said Kohl. “You can also use these observations for your own investigations and interact with a vibrant community of individuals from around the world who care about Earth system science and our global environment.”
Clouds are a dynamic part of the Earth’s climate system. Depending on their type, their altitude, and even the size of their water droplets, they either trap heat in the atmosphere, or reflect sunlight back into space. We have satellites to observe and study clouds, but they have their limitations. An army of citizen scientists observing their local cloud population will add a lot to the efforts of the satellites.
“Clouds are one of the most important factors in understanding how climate is changing now and how it’s going to change in the future,” Kohl said. “NASA studies clouds from satellites that provide either a top view or a vertical slice of the clouds. The ground-up view from citizen scientists is valuable in validating and understanding the satellite observations. It also provides a more complete picture of clouds around the world.”
The observations collected by GLOBE users could end up as part of NASA’s Earth Observatory, which tracks the cloud fraction around the world. Image: NASA/NASA Earth Observation.
The GLOBE team has issued a challenge to any interested citizen scientists who want to use the app. Over the next two weeks, the team is hoping that users will make ground observations of clouds at the same time as a cloud-observing satellite passes overhead. “We really encourage all citizen scientists to look up in the sky and take observations while the satellites are passing over through Sept. 14,” said Kohl.
The app makes this easy to do. It informs users when a satellite will be passing overhead, so we can do a quick observation at that time. We can also use Facebook or Twitter to view daily maps of the satellite’s path.
“Ground measurements are critical to validate measurements taken from space through remote sensing,” said Erika Podest, an Earth scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who is working with GLOBE data. “There are some places in the world where we have no ground data, so citizen scientists can greatly contribute to advancing our knowledge this important part of the Earth system.”
The app itself seems pretty straightforward. I checked for upcoming satellite flyovers and was notified of 6 flyovers that day. It’s pretty quick and easy to step outside and take an observation at one of those times.
I did a quick observation from the street in front of my house and it took about 2 minutes. To identify cloud types, you just match what you see with in-app photos of the different types of clouds. Then you estimate the percentage of cloud cover, or specify if the sky is obscured by blowing snow, or fog, or something else. You can also add pictures, and the app guides you in aiming the camera properly.
The GLOBE Observer app is easy to use, and kind of fun. It’s simple enough to fit a quick cloud observation in between selfies and meal pictures.
Download it and try it out.
You can download the IOS version from the App Store, and the Android version from Google Play.
Artist's concept of Sagittarius A, the supermassive black hole at the center of our galaxy. Credit: NASA/JPL
6 million years ago, when our first human ancestors were doing their thing here on Earth, the black hole at the center of the Milky Way was a ferocious place. Our middle-aged, hibernating black hole only munches lazily on small amounts of hydrogen gas these days. But when the first hominins walked the Earth, Sagittarius A was gobbling up matter and expelling gas at speeds reaching 1,000 km/sec. (2 million mph.)
The evidence for this hyperactive phase in Sagittarius’ life, when it was an Active Galactic Nucleus (AGN), came while astronomers were searching for something else: the Milky Way’s missing mass.
There’s a funny problem in our understanding of our galactic environment. Well, it’s not that funny. It’s actually kind of serious, if you’re serious about understanding the universe. The problem is that we can calculate how much matter we should be able to see in our galaxy, but when we go looking for it, it’s not there. This isn’t just a problems in the Milky Way, it’s a problem in other galaxies, too. The entire universe, in fact.
Our measurements show that the Milky Way has a mass about 1-2 trillion times greater than the Sun. Dark matter, that mysterious and invisible hobgoblin that haunts cosmologists’ nightmares, makes up about five sixths of that mass. Regular, normal matter makes up the last sixth of the galaxy’s mass, about 150-300 billion solar masses. But we can only find about 65 billion solar masses of that normal matter, made up of the familiar protons, neutrons, and electrons. The rest is missing in action.
Astrophysicists at the Harvard-Smithsonian Center for Astrophysics have been looking for that mass, and have written up their results in a new paper.
“We played a cosmic game of hide-and-seek. And we asked ourselves, where could the missing mass be hiding?” says lead author Fabrizio Nicastro, a research associate at the Harvard-Smithsonian Center for Astrophysics (CfA) and astrophysicist at the Italian National Institute of Astrophysics (INAF).
“We analyzed archival X-ray observations from the XMM-Newton spacecraft and found that the missing mass is in the form of a million-degree gaseous fog permeating our galaxy. That fog absorbs X-rays from more distant background sources,” Nicastro continued.
Artist’s impression of the ESA’s XMM Newton Spacecraft. Image credit: ESA
Nicastro and the other scientists behind the paper analyzed how the x-rays were absorbed and were able to calculate the amount and distribution of normal matter in that fog. The team relied heavily on computer models, and on the XMM-Newton data. But their results did not match up with a uniform distribution of the gaseous fog. Instead, there is an empty “bubble”, where this is no gas. And that bubble extends from the center of the galaxy two-thirds of the way to Earth.
What can explain the bubble? Why would the gaseous fog not be spread more uniformly through the galaxy?
Clearing gas from an area that large would require an enormous amount of energy, and the authors point out that an active black hole would do it. They surmise that Sagittarius A was very active at that time, both feeding on gas falling into itself, and pumping out streams of hot gas at up to 1000 km/sec.
Which brings us to present day, 6 million years later, when the shock-wave caused by that activity has travelled 20,000 light years, creating the bubble around the center of the galaxy.
Another piece of evidence corroborates all this. Near the galactic center is a population of 6 million year old stars, formed from the same material that at one time flowed toward the black hole.
“The different lines of evidence all tie together very well,” says Smithsonian co-author Martin Elvis (CfA). “This active phase lasted for 4 to 8 million years, which is reasonable for a quasar.”
The numbers all match up, too. The gas accounted for in the team’s models and observations add up to 130 billion solar masses. That number wraps everything up pretty nicely, since the missing matter in the galaxy is thought to be between 85 billion and 235 billion solar masses.
This is intriguing stuff, though it’s certainly not the final word on the Milky Way’s missing mass. Two future missions, the European Space Agency’s Athena X-ray Observatory, planned for launch in 2028, and NASA’s proposed X-Ray Surveyor could provide more answers.
Who knows? Maybe not only will we learn more about the missing matter in the Milky Way and other galaxies, we may learn more about the activity at the center of the galaxy, and what ebbs and flows it has gone through, and how that has shaped galactic evolution.
An artist's concept of the Europa mission. The multi-year mission would conduct fly-bys of Europa designed to protect it from the extreme environment there. Image: NASA/JPL-Caltech
Jupiter’s moon Europa is a juicy target for exploration. Beneath its surface of ice there’s a warm salty, ocean. Or potentially, at least. And if Earth is our guide, wherever you find a warm, salty, ocean, you find life. But finding it requires a dedicated, and unique, mission.
If each of the bodies in our Solar System weren’t so different from each other, we could just have one or two types of missions. Things would be much easier, but also much more boring. But Europa isn’t boring, and it won’t be easy to explore. Exploring it will require a complex, custom mission. That means expensive.
NASA’s proposed mission to Europa is called the Europa Clipper. It’s been in the works for a few years now. But as the mission takes shape, and as the science gets worked out, a parallel process of budget wrangling is also ongoing. And as reported by SpaceNews.com there could be bad news incoming for the first-ever mission to Europa.
Images from NASA’s Galileo spacecraft show the intricate detail of Europa’s icy surface. Image: NASA/JPL-Caltech/ SETI Institute
At issue is next year’s funding for the Europa Clipper. Officials with NASA’s Outer Planets Assessment Group are looking for ways to economize and cut costs for Fiscal Year (FY) 2017, while still staying on track for a mission launch in 2022.
According to Bob Pappalardo, Europa Clipper’s project scientist at the Jet Propulsion Laboratory, funding will be squeezed in 2017. “There is this squeeze in FY17 that we have,” said Pappalardo. “We’re asking the instrument teams and various other aspects of the project, given that squeeze, what will it take in the out years to maintain that ’22 launch.”
As for the actual dollar amounts, there are different numbers floating around, and they don’t all jive with each other. In 2016, the Europa Mission received $175 million from Congress, but in the administration’s budget proposal for 2017, they only requested $49.6 million.
There’s clearly some uncertainty in these numbers, and that uncertainty is reflected in Congress, too. An FY 2017 House bill earmarks $260 million for the Europa mission. And the Senate has crafted a bill in support of the mission, but doesn’t allocate any funding for it. Neither the Senate nor the Congress has passed their bills.
This is not the first time that a mis-alignment has appeared between NASA and the different levels of government when it comes to funding. It’s pretty common. It’s also pretty common for the higher level of funding to prevail. But it’s odd that NASA’s requested amount is so low. NASA’s own low figure of $49.6 million is fuelling the perception that they themselves are losing interest in the Europa Clipper.
But SpaceNews.com is reporting that that is not the case. According to Curt Niebur, NASA’s program scientist for the Europa mission, “Everyone is aware of how supportive and generous Congress has been of this mission, and I’m happy to say that that support and encouragement is now shared by the administration, and by NASA as well. Everybody is on board the Europa Clipper and getting this mission to the launch pad as soon as our technical challenges and our budget will allow.”
What all this seems to mean is that the initial science and instrumentation for the mission will be maintained, but no additional capacity will be added. NASA is no longer considering things like free-flying probes to measure the plumes of water ice coming off the moon. According to Niebur, “The additional science value provided by these additions was not commensurate with the associated impact to resources, to accommodation, to cost. There just wasn’t enough science there to balance that out.”
The Europa Clipper will be a direct shot to Europa, without any gravity assist on the way. It will likely be powered by the Space Launch System. The main goal of the mission is to learn more about the icy moon’s potential habitability. There are tantalizing clues that it has an ocean about 100 km thick, kept warm by the gravity-tidal interactions with Jupiter, and possibly by radioactive decay in the rocky mantle. There’s also some evidence that the composition of the sub-surface ocean is similar to Earth’s.
Mars is a fascinating target, no doubt about it. But as far as harbouring life, Europa might be a better bet. Europa’s warm, salty ocean versus Mar’s dry, cold surface? A lot of resources have been spent studying Mars, and the Europa mission represents a shift in resources in that regard.
It’s unfortunate that a few tens of million dollars here or there can hamper our search for life beyond Earth. But the USA is a democracy, so that’s the way it is. These discrepancies and possible disputes between NASA and the different levels of government may seem disconcerting, but that’s the way these things get done.
