"Space weather scientist Liz MacDonald has seen auroras more than five times in her life, but it was the aurora she didn't see that affected her the most. On the evening of Oct. 24, 2011, MacDonald was sitting in front of her computer at her home in Los Alamos, New Mexico. Forecasts predicted a geomagnetic storm would hit Earth that night and potentially create beautiful aurora. The aurora didn't come to Los Alamos, but MacDonald was still amazed -- not by any bright, dancing lights in the sky, but by the number of aurora-related tweets on her computer screen. People across the eastern United States, from Alabama to Chicago, tweeted about seeing the aurora in real-time. This storm became one of the first wide-scale documentations of aurora activity with social media."
Recently in Citizen Science Category
We investigate the development of scientific content knowledge of volunteers participating in online citizen science projects in the Zooniverse (www.zooniverse.org), including the astronomy projects Galaxy Zoo (www.galaxyzoo.org) and Planet Hunters (www.planethunters.org). We use econometric methods to test how measures of project participation relate to success in a science quiz, controlling for factors known to correlate with scientific knowledge. Citizen scientists believe they are learning about both the content and processes of science through their participation. Won't don't directly test the latter, but we find evidence to support the former - that more actively engaged participants perform better in a project-specific science knowledge quiz, even after controlling for their general science knowledge. We interpret this as evidence of learning of science content inspired by participation in online citizen science.
"We have developed a crowdsourcing web application for image quality control employed by the Dark Energy Survey. Dubbed the "DES exposure checker", it renders science-grade images directly to a web browser and allows users to mark problematic features from a set of predefined classes. Users can also generate custom labels and thus help identify previously unknown problem classes. User reports are fed back to hardware and software experts to help mitigate and eliminate recognized issues. We report on the implementation of the application and our experience with its over 100 users, the majority of which are professional or prospective astronomers but not data management experts. We discuss aspects of user training and engagement, and demonstrate how problem reports have been pivotal to rapidly correct artifacts which would likely have been too subtle or infrequent to be recognized otherwise. We conclude with a number of important lessons learned, suggest possible improvements, and recommend this collective exploratory approach for future astronomical surveys or other extensive data sets with a sufficiently large user base."
"So you want to be a citizen scientist? The National Science Foundation (NSF) has got you covered. NSF supports citizen science and crowdsourcing efforts across all areas of science, whether your passion is to scan the night sky, explore your own backyard or play video games. Projects such as these are highlighted at a White House Forum on Citizen Science and Crowdsourcing, a celebration of open science and innovation on Sept. 30. Citizen science not only opens new research avenues, but brings diverse perspectives and skill sets to research, and allows everyone to deepen their understanding and appreciation for science."
"Around 37,000 citizen scientists combed through 430,000 images to help an international team of researchers to discover 29 new gravitational lens candidates through Space Warps, an online classification system which guides citizen scientists to become lens hunters. Gravitational lens systems are massive galaxies that act like special lenses through their gravity, bending the light coming from a distant galaxy in the background and distorting its image. Dark matter around these massive galaxies also contributes to this lensing effect, and so studying these gravitational lenses gives scientists a way to study this exotic matter that emits no light. Since gravitational lenses are rare, only about 500 of them have been discovered to date, and the universe is enormous, it made sense for researchers to call on an extra pair of eyes to help scour through the mountain of images taken from the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). Details of the discoveries will be published in Monthly Notices of the Royal Astronomical Society."
"Trained volunteers are as good as professional astronomers at finding jets shooting from massive black holes and matching them to their host galaxies, research suggests. Scientists working on citizen science project Radio Galaxy Zoo developed an online tutorial to teach volunteers how to spot black holes and other objects that emit large amounts of energy through radio waves. Through the project, volunteers are given telescope images taken in both the radio and infrared part of the electromagnetic spectrum and asked to compare the pictures and match the "radio source" to the galaxy it lives in. The results from the first year of the Radio Galaxy Zoo project, led by Dr Julie Banfield of the ARC Centre of Excellence for All-Sky Astrophysics and Dr Ivy Wong at the International Centre for Radio Astronomy Research, were published today in the Monthly Notices of the Royal Astronomical Society."
The questions about the origin and type of cosmic particles are not only fascinating for scientists in astrophysics, but also for young enthusiastic high school students. To familiarize them with research in astroparticle physics, the Pierre Auger Collaboration agreed to make 1% of its data publicly available. The Pierre Auger Observatory investigates cosmic rays at the highest energies and consists of more than 1600 water Cherenkov detectors, located near Malargüe, Argentina. With publicly available data from the experiment, students can perform their own hands-on analysis. In the framework of a so-called Astroparticle Masterclass organized alongside the context of the German outreach network Netzwerk Teilchenwelt, students get a valuable insight into cosmic ray physics and scientific research concepts. We present the project and experiences with students.
"A new NASA challenge is looking for evidence to support a theory that electromagnetic pulses (EMP) may precede an earthquake, potentially offering a warning to those in the quake's path. The "Quest for Quakes" two-week algorithm challenge seeks to develop new software codes or algorithms to search through data and identify electromagnetic pulses that may precede an earthquake. Some researchers have speculated such pulses originating from the ground near earthquake epicenters could signal the onset of some quakes. "Developing a reliable approach that can separate potential earthquake-induced electromagnetic pulses from the myriad of natural and anthropogenic sources has been a significant challenge," said Craig Dobson, program scientist at NASA Headquarters in Washington. "We look forward to seeing the innovative ideas from this competition and learning more about this controversial phenomenon.""
"Science-team members for NASA's Mars Reconnaissance Orbiter are soliciting help from the public to analyze exotic features near the south pole of Mars. By categorizing features visible in images from the orbiter's Context Camera (CTX), volunteers are using their own computers to help the team identify specific areas for even more detailed examination with the orbiter's High Resolution Imaging Science Experiment (HiRISE) camera. HiRISE can reveal more detail than any other camera ever put into orbit around Mars. Planet Four: Terrains is on a new platform released by the Zooniverse, an organization that currently hosts 30 projects that enlist people worldwide to contribute to discoveries in fields ranging from astronomy to zoology. The new platform is designed to make it easier than ever for a researcher needing help with data analysis to set up a task to involve volunteers."
"A 15-yr-old schoolboy has discovered a new planet orbiting a star 1000 light years away in our galaxy. Tom Wagg was doing work-experience at Keele University when he spotted the planet by finding a tiny dip in the light of a star as a planet passed in front of it. ``I'm hugely excited to have a found a new planet, and I'm very impressed that we can find them so far away'', says Tom, now aged 17. It has taken two years of further observations to prove that Tom's discovery really is a planet."
"As millions of people regroup from the impact of the earthquakes in Nepal, a team of international volunteers is combing through satellite imagery of the region to identify additional hazardsearthquake-induced landslides. As part of a disaster relief response to the 7.8-magnitude Nepal earthquake and its aftershocks, Kirschbaum and Jeff Kargel, glaciologist at University of Arizona, are leading a group of volunteer scientists identifying where and when the landslides are occurring in earthquake-affected areas. Together, the team has mapped nearly one thousand landslides from April 25, the date of the first earthquake, to May 20."
"Every morning at seven, Andrew Welch wakes up, cooks breakfast and checks the rain gauge sitting on a five-foot post in his backyard. He writes down the measurement, sends his kid off to school and then heads out to his workplace as a structural engineer. Welch is a citizen scientist. Around the world, hundreds of citizen scientists like him are collecting precipitation measurements from the ground that are useful for NASA's Global Precipitation Measurement (GPM) mission. GPM is an international satellite mission led by NASA and the Japan Aerospace Exploration Agency that provides rain and snow observations from space around the globe every three hours. GPM's data will improve our understanding of water and energy cycles and extreme weather events, such as hurricanes, monsoons and droughts."
"The Citizen science Asteroid Data, Education, and Tools (CADET) is a joint solicitation of the Near Earth Objects (NEO) Program within NASA's Science Mission Directorate (SMD) and the Asteroid Grand Challenge (AGC) program within NASA's Office of the Chief Technologist (OCT). It seeks innovative proposals to adapt, develop, and web-enable software tools for asteroid data analysis and to make them accessible and easily usable by nonprofessionals, including amateur astronomers, students, and citizen scientists."
"A team of highly determined high school students discovered a never-before-seen pulsar by painstakingly analyzing data from the National Science Foundation's (NSF) Robert C. Byrd Green Bank Telescope (GBT). Further observations by astronomers using the GBT revealed that this pulsar has the widest orbit of any around a neutron star and is part of only a handful of double neutron star systems. This impressive find will help astronomers better understand how binary neutron star systems form and evolve. This pulsar, which received the official designation PSR J1930-1852, was discovered in 2012 by Cecilia McGough, who was a student at Strasburg High School in Virginia at the time, and De'Shang Ray, who was a student at Paul Laurence Dunbar High School in Baltimore, Maryland."
"More than 40,000 amateur astronomers have classified two million unidentified heavenly bodies found by the SkyMapper telescope at The Australian National University (ANU). Among the haystack of celestial data, the volunteers uncovered five sought-after supernovas, extremely bright exploding stars, which provide crucial information about the history and future of the universe. "It was a huge success, everyone was really excited to take part," said Dr Richard Scalzo, from the ANU Research School of Astronomy and Astrophysics. "One volunteer was so determined to find a supernova that he stayed online for 25 hours. Unfortunately he didn't find one, but he did find an unusual variable star, which we think might explode in the next 700 million years or so." The SkyMapper telescope, at the Siding Spring Observatory near Coonabarabran in central New South Wales, is creating a digital survey of the entire southern sky with a detailed record of more than a billion stars and galaxies."
"NASA has announced the release of Vesta Trek, a free, web-based application that provides detailed visualizations of Vesta, one of the largest asteroids in our solar system. NASA's Dawn spacecraft studied Vesta from July 2011 to September 2012. Data gathered from multiple instruments aboard Dawn have been compiled into Vesta Trek's user-friendly set of tools, enabling citizen scientists and students to study the asteroid's features. Vesta Trek was developed by NASA's Lunar Mapping and Modeling Project (LMMP), which provides mission planners, lunar scientists and the public with analysis and data visualization tools for our moon, spanning multiple instruments on multiple missions. Vesta Trek represents the first application of LMMP's capabilities to another world beyond the moon. LMMP-based portals for other worlds in our Solar System are currently in development."
"We find that the RGZ citizen scientists are as effective as the science experts at identifying the radio sources and their host galaxies. Based upon our results from 1 year of operation, we find the RGZ host galaxies reside in 3 primary loci of mid-infrared colour space. The mid-infrared colour space is defined by the WISE filter bands: W1, W2 and W3, corresponding to 3.4, 4.6 and 12 microns; respectively."
"On 2015 March 20, a total solar eclipse will occur in the North Atlantic, with the Kingdom of Denmark's Faroe Islands and Norway's Svalbard archipelago (formerly Spitzbergen) being the only options for land-based observing. The region is known for wild, unpredictable, and often cloudy conditions, which potentially pose a serious threat for people hoping to view the spectacle. We report on a citizen-science, weather-monitoring project, based in the Faroe Islands, which was conducted in March 2014 - one year prior to the eclipse. The project aimed to promote awareness of the eclipse among the local communities, with the data collected providing a quantitative overview of typical weather conditions that may be expected in 2015. It also allows us to validate the usefulness of short-term weather forecasts, which may be used to increase the probability of observing the eclipse."
"We develop a method to enable collaborative modelling of gravitational lenses and lens candidates, that could be used by non-professional lens enthusiasts. It uses an existing free-form modelling program (glass), but enables the input to this code to be provided in a novel way, via a user-generated diagram that is essentially a sketch of an arrival-time surface. We report on an implementation of this method, SpaghettiLens, which has been tested in a modelling challenge using 29 simulated lenses drawn from a larger set created for the Space Warps citizen science strong lens search. We find that volunteers from this online community asserted the image parities and time ordering consistently in some lenses, but made errors in other lenses depending on the image morphology."
The NOAA National Severe Storms Laboratory is collecting public weather reports through a free app available for smart phones or mobile devices. The app is called "mPING," for Meteorological Phenomena Identification Near the Ground. mPING reports are immediately archived into a database at NSSL, and are displayed on a map accessible to anyone. To use the app, reporters select the type of weather that is occurring, and tap "submit." The anonymous reports can be submitted as often as every minute.
"The search for life in space involves scientists of all stripes--biologists, physicists, astronomers, chemists...and geologists? NASA-funded UW-Madison geoscientists use Earth's rock and fossil record to shape the search for life in our solar system and beyond. At this DIY event, you'll explore the creative ways these researchers are trying to answer the age-old question: Are we alone? This event is in collaboration with the Department of Geoscience and NASA-funded UW-Madison geoscientists part of the NASA Astrobiology Institute."
"A NASA-sponsored website designed to crowdsource analysis of data from the agency's Wide-field Infrared Survey Explorer (WISE) mission has reached an impressive milestone. In less than a year, citizen scientists using DiskDetective.org have logged 1 million classifications of potential debris disks and disks surrounding young stellar objects (YSO). This data will help provide a crucial set of targets for future planet-hunting missions. "This is absolutely mind-boggling," said Marc Kuchner, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the project's principal investigator. "We've already broken new ground with the data, and we are hugely grateful to everyone who has contributed to Disk Detective so far."
Students from Connetquot High School in Bohemia, New York, used astronaut imagery of Earth to compare impact craters on Earth with those on other planets. The images were provided through the Expedition Earth and Beyond (EEAB) program, which connects students in grades 5 and higher with pictures taken by astronauts aboard the International Space Station. "The images provide a hook for students to formulate questions, think about how to collect and analyze data, and then draw their own conclusions," says EEAB Director Paige Graff. "The whole idea is authentic science you can do in the classroom, to give students an experience based on their interests and motivation."
"Why do we need your help? The images you're looking at come from Landsat images taken every 16 days from 1984 to the present. When one of our project scientists first began working with these images, he had hoped he could just throw the hundreds of thousands of images into some image classification software, and have the software tell him where kelp was located. There's just one problem: Kelp is tricky. Landsat was not designed to be able to see kelp. Kelp's reflectance signature is just at the edge of its detection abilities."
NASA in partnership with the U.S. Geological Survey (USGS) is offering more than $35,000 in prizes to citizen scientists for ideas that make use of climate data to address vulnerabilities faced by the United States in coping with climate change. The Climate Resilience Data Challenge, conducted through the NASA Tournament Lab, a partnership with Harvard University hosted on Appirio/Topcoder, kicks off Monday, Dec 15 and runs through March 2015. The challenge supports the efforts of the White House Climate Data Initiative, a broad effort to leverage the federal government's extensive, freely available climate-relevant data resources to spur innovation and private-sector entrepreneurship in order to advance awareness of and preparedness for the impacts of climate change. The challenge was announced by the White House Office of Science and Technology Policy Dec. 9.
"Help us to georeference the position of cities which appear in the ISS images. We are members of the Group of Extragalactic Astrophysics and Astronomical Instrumentation from the of Universidad Coplutense de Madrid. Among our activities is a study of light pollution and the energy consumption derived from it. We use images taken from the International Space Station as part of our investigations, provided by Earth Science and Remote Sensing Unit, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth." To compare the images with the different light sources on the earth, we need to know the city's location. Due to the large number of images, we need your help. Some of these pictures are from unknown locations for us, and it is very difficult to identify them in the pictures. However, a lot of people around the world will know the cities. We need you to identify the cities and connect them with their position point on the map. This application allows you to do this."
"I discovered that one amateur astronomer had already posted online about how he had detected a known exoplanet using a digital single-lens reflex (DSLR) camera outfitted with a telephoto lens. He was able to discern the dip in the brightness of a star as an orbiting planet passed in front of it - a technique known as transit detection. The exoplanet he chose to go after was a gas giant that belongs to a binary star system variously named HD 189733, HIP 98505, or V452 Vulpeculae, depending on the star catalog."
More: DIY Exoplanet Detector, IEEE Spectrum
Also: Detect known exoplanet with DSLR/telephote lens, Cloudy Nights
"4-H groups were soon cratering their neighborhoods and farmers tilling their fields in search of otherworldly harvest. The project surely marks the only official liaison between NASA's Goddard Space Flight Center in Maryland and Pottawattamie County, Iowa's Agricultural Extension; the latter reported being "swamped with samples worthy of a geological museum." A mountain of would-be moon material was submitted for testing at NASA's Ames Research Center in California. Promising specimens were crushed, examined by microscope and spectrograph, then probed for evidence of the superheating and cosmic-ray activity characteristic of exposure to space and atmospheric entry to Earth. Yet the project's final harvest, including smokestack clinkers (bits of residue blasted aloft during burning or smelting) and even fossils, produced nothing extraterrestrial. So the effort, after running just short of a year, ended in March 1965, with each sample returned to its sender, along with a letter of thanks."
More: Searching for Moon Rocks in Iowa, Air & Space
"The app lets citizen scientists like you measure how bright the night sky is, by seeing which stars you are able to see. The more faint stars you can see, the more natural your sky is. Your results are then shared with the GLOBE at Night project, and will be used to track how the night sky is changing in response to widespread adoption of LED lights."
In winter time, when nights become longer and darker, stargazing can be a fantastic experience and family activity. But in urban areas, the stars disappear behind the skyglow caused by waste light that shines up into the sky. This light pollution is not only a problem for astronomy. Scientists from the interdisciplinary project "Loss of the Night" study how it affects health, society, and the environment. In order to measure how skyglow is changing, they have developed an app for smartphones, which allows citizen scientists to count the number of visible stars in the night sky. The app, originally only available for Android, has now been expanded to support Apple's iOS."
"Skybox Imaging, one of the more recent acquisitions of Google, announced at the company's yearly Geo for Good User Summit that it is launching the Skybox for Good program. Under the program, Google and Skybox will be providing updated satellite images to several projects that "save lives, protect the environment, promote education, and positively impact humanity," wrote Julian Mann, co-founder of Skybox and Develop Advocate for Google Earth Outreach, on the official blog for Skybox. According to Mann, when Skybox started in 2009, the founding members already knew that the company's imaging services could bring positive changes to the world. As soon as the company's SkySat-1 imaging satellite was launched to orbit, Skybox already started monitoring critical sites for the tracking of climate change. One of these locations is Greenland's Helheim Glacier."
Measurements by thousands of citizen scientists in the Netherlands using their smartphones and the iSPEX add-on are delivering accurate data on dust particles in the atmosphere that add valuable information to professional measurements. The iSPEX team, led by Frans Snik of Leiden University, analyzed all measurements from three days in 2013 and combined them into unique maps of dust particles above the Netherlands. The results match and sometimes even exceed those of ground-based measurement networks and satellite instruments.
"NASA is inviting people around the globe to step outside during Earth Science Week, Oct. 12-18, observe the sky and share their observations as citizen scientists. NASA's #SkyScience activity is part of an annual educational event organized by the American Geosciences Institute to encourage the public to engage in Earth sciences. Citizen scientists can participate in this global Earth science data collection event by observing, photographing and reporting on clouds over their location as a NASA satellite passes over. Reports and photos will be compared to data collected by NASA Earth-observing instruments as a way to assess the satellite measurements."
Citizen Scientists Probe Early Galaxies, Sky and Telescope
"Now, astronomers using data collected by Galaxy Zoo -- a crowd-sourced astronomy project that invites the public to analyze fuzzy images of distant galaxies -- are peering deeper into the universe in search of these barred galaxies. "Galaxy Zoo works because spotting features in galaxies is a task well suited to humans. We as a species are great at pattern recognition," says project astronomer Brooke Simmons (Oxford, U.K.). "And you don't need to be an astrophysicist to recognize a boxy shape inside a rounded disk."
"The increasing importance of digital sky surveys collecting many millions of galaxy images has reinforced the need for robust methods that can perform morphological analysis of large galaxy image databases. Citizen science initiatives such as Galaxy Zoo showed that large datasets of galaxy images can be analyzed effectively by non-scientist volunteers, but since databases generated by robotic telescopes grow much faster than the processing power of any group of citizen scientists, it is clear that computer analysis is required. Here we propose to use citizen science data for training machine learning systems, and show experimental results demonstrating that machine learning systems can be trained with citizen science data. Our findings show that the performance of machine learning depends on the quality of the data, which can be improved by using samples that have a high degree of agreement between the citizen scientists. The source code of the method is publicly available."
"NASA announced Saturday the opening of registration for its Mars Balance Mass Challenge and the launch of its new website, NASA Solve, at the World Maker Faire in New York. "NASA is committed to engaging the public, and specifically the maker community through innovative activities like the Mars Balance Mass Challenge," said NASA Chief Technologist David Miller. "And NASA Solve is a great way for members of the public, makers and other citizen scientists to see all NASA challenges and prizes in one location."
"The knowledge commons research framework is applied to a case of commons governance grounded in research in modern astronomy. The case, Galaxy Zoo, is a leading example of at least three different contemporary phenomena."
"The most productive citizen astronomy projects involve close collaboration between the professionals and amateurs involved, and occupy scientific niches not easily filled by great observatories or machine learning methods: citizen astronomers are most strongly motivated by being of service to science. In the coming years we expect participation and productivity in citizen astronomy to increase, as survey datasets get larger and citizen science platforms become more efficient. Opportunities include engaging the public in ever more advanced analyses, and facilitating citizen-led enquiry by designing professional user interfaces and analysis tools with citizens in mind."
"Digitizing the ~500,000 glass plate images covering the full sky will foster new scientific discoveries for the currently 'hot' field of studying variability of astronomical objects, or time domain astronomy, as we bring to light these long-hidden archives," says Harvard professor Josh Grindlay, the leader of the Digital Access to a Sky Century at Harvard (DASCH) project. The telescope logbooks record vital information associated with a 100-year-long effort to record images of the sky. By transcribing logbook text to put those historical observations in context, volunteers can help to unlock hidden discoveries."
The Influence of Social Movements on Space Astronomy Policy, Hannah E. Harris, Pedro Russo
"Public engagement (PE) initiatives can lead to a long term public support of science. However most of the real impact of PE initiatives within the context of long-term science policy is not completely understood. An examination of the National Aeronautics and Space Administration's (NASA) Hubble Space Telescope, James Webb Space Telescope, and International Sun-Earth Explorer 3 reveal how large grassroots movements led by citizen scientists and space aficionados can have profound effects on public policy. We explore the role and relevance of public grassroots movements in the policy of space astronomy initiatives, present some recent cases which illustrate policy decisions involving broader interest groups, and consider new avenues of PE including crowdfunding and crowdsourcing."
Accepted for publication in Space Policy journal. Full Paper
"With the help of a distributed science project called Stardust@home, volunteer space enthusiasts from around the world combed through the video, flagging tracks they believed were created by interstellar dust."
Space Aliens Are Already Here, Huffington Post
"A critical aspect of this was the dedication and hard work of the citizen scientists who worked on this," Westphal said. "We couldn't have done it without them." In fact, two of those Dusters, Bruce Hudson from Midland, Ontario, Canada, and Naomi Wordsworth from Wexbury, South Buckinghamshire, United Kingdom, were allowed to name the interstellar particles they found: Orion and Hylabrook, respectively. They are listed with the 66 scientist co-authors of the Science paper. Weshphal himself discovered the third interstellar dust track in the aerogels and called it Sorok, the Russian word for 40, the number attached to the track."
"NASA is launching two challenges to give the public an opportunity to create innovative ways to use data from the agency's Earth science satellites. The challenges will use the Open NASA Earth Exchange. OpenNEX is a data, supercomputing and knowledge platform where users can share modeling and analysis codes, scientific results, knowledge and expertise to solve big data challenges in the Earth sciences. A component of the NASA Earth Exchange, OpenNEX provides users a large collection of climate and Earth science satellite data sets, including global land surface images, vegetation conditions, climate observations and climate projections."
'Hot or Not?' Trinity Astrophysicists Ask Public to Rank Sunspots, Trinity College Dublin
'Sunspots' and 'solar storms' are the feature of an ambitious project being launched internationally by astrophysicists at Trinity College Dublin today. Members of the public will work as part of a global team to better understand sunspot and solar storm phenomena and their impacts on Earth. They will do this by 'rating' the relative complexity of each sunspot image they see on the Sunspotter website, based on its size, shape and arrangement of 'magnetic blobs'.
"We present Brut, an algorithm to identify bubbles in infrared images of the Galactic midplane. Brut is based on the Random Forest algorithm, and uses bubbles identified by >35,000 citizen scientists from the Milky Way Project to discover the identifying characteristics of bubbles in images from the Spitzer Space Telescope. We demonstrate that Brut's ability to identify bubbles is comparable to expert astronomers. We use Brut to re-assess the bubbles in the Milky Way Project catalog, and find that 10-30% of the objects in this catalog are non-bubble interlopers."