A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the surface topography and composition of the sample. The electron beam is scanned in a raster scan pattern, and the position of the beam is combined with the intensity of the detected signal to produce an image. In the most common SEM mode, secondary electrons emitted by atoms excited by the electron beam are detected using a secondary electron detector. The number of secondary electrons that can be detected, and thus the signal intensity, depends, among other things, on specimen topography. Some SEMs can achieve resolutions better than 1 nanometer.
In astronomy, the interstellar medium (ISM) is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space. The energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation field.
Outer space is the expanse that exists beyond Earth and between celestial bodies. Outer space is not completely empty—it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays. The baseline temperature of outer space, as set by the background radiation from the Big Bang, is 2.7 kelvins. The plasma between galaxies is thought to account for about half of the baryonic (ordinary) matter in the universe, having a number density of less than one hydrogen atom per cubic metre and a temperature of millions of kelvins. Local concentrations of matter have condensed into stars and galaxies. Studies indicate that 90% of the mass in most galaxies is in an unknown form, called dark matter, which interacts with other matter through gravitational but not electromagnetic forces. Observations suggest that the majority of the mass-energy in the observable universe is dark energy, a type of vacuum energy that is poorly understood. Intergalactic space takes up most of the volume of the universe, but even galaxies and star systems consist almost entirely of empty space.
Stardust was a 390-kilogram robotic space probe launched by NASA on 7 February 1999. Its primary mission was to collect dust samples from the coma of comet Wild 2, as well as samples of cosmic dust, and return these to Earth for analysis. It was the first sample return mission of its kind. En route to comet Wild 2, the craft also flew by and studied the asteroid 5535 Annefrank. The primary mission was successfully completed on 15 January 2006, when the sample return capsule returned to Earth.
The University of Hawaiʻi System, formally the University of Hawaiʻi and popularly known as UH, is a public college and university system that confers associate, bachelor's, master's, and doctoral degrees through three universities, seven community colleges, an employment training center, three university centers, four education centers and various other research facilities distributed across six islands throughout the state of Hawaii in the United States. All schools of the University of Hawaiʻi system are accredited by the Western Association of Schools and Colleges. The UH system's main administrative offices are located on the property of the University of Hawaiʻi at Mānoa in Honolulu CDP.
The Copernican Period in the lunar geologic timescale runs from approximately 1.1 billion years ago to the present day. The base of the Copernican period is defined by impact craters that possess bright optically immature ray systems. The crater Copernicus is a prominent example of rayed crater, but it does not mark the base of the Copernican period.
Thomas Eugene Everhart FREng is an American educator and physicist. His area of expertise is the physics of electron beams. Together with Richard F. M. Thornley he designed the Everhart–Thornley detector. These detectors are still in use in scanning electron microscopes, even though the first such detector was made available as early as 1956.
An electron microprobe (EMP), also known as an electron probe microanalyzer (EPMA) or electron micro probe analyzer (EMPA), is an analytical tool used to non-destructively determine the chemical composition of small volumes of solid materials. It works similarly to a scanning electron microscope: the sample is bombarded with an electron beam, emitting x-rays at wavelengths characteristic to the elements being analyzed. This enables the abundances of elements present within small sample volumes to be determined, when a conventional accelerating voltage of 15-20 kV is used. The concentrations of elements from lithium to plutonium may be measured at levels as low as 100 parts per million (ppm), material dependent, although with care, levels below 10 ppm are possible The ability to quantify lithium by EPMA became a reality in 2008.
Cosmic dust, also called extraterrestrial dust or space dust, is dust which exists in outer space, or has fallen on Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm. Larger particles are called meteoroids. Cosmic dust can be further distinguished by its astronomical location: intergalactic dust, interstellar dust, interplanetary dust and circumplanetary dust.
The Department of Materials at the University of Oxford, England was founded in the 1950s as the Department of Metallurgy, by William Hume-Rothery, who was a reader in Oxford's Department of Inorganic Chemistry. It is part of the university's Mathematical, Physical and Life Sciences Division
Dante S. Lauretta is a professor of planetary science and cosmochemistry at the University of Arizona's Lunar and Planetary Laboratory. He is currently serving as the principal investigator on NASA's OSIRIS-REx mission.
Klaus Keil is a professor at the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawai'i at Manoa. He is the former Director of the Hawaii Institute of Geophysics and Planetology. He is also the former director of the University of New Mexico Institute of Meteoritics. Klaus pioneered the use of the electron microprobe to study meteorite samples. He is one of the co-inventors of the Energy dispersive X-ray spectrometer.
Characterization, when used in materials science, refers to the broad and general process by which a material's structure and properties are probed and measured. It is a fundamental process in the field of materials science, without which no scientific understanding of engineering materials could be ascertained. The scope of the term often differs; some definitions limit the term's use to techniques which study the microscopic structure and properties of materials, while others use the term to refer to any materials analysis process including macroscopic techniques such as mechanical testing, thermal analysis and density calculation. The scale of the structures observed in materials characterization ranges from angstroms, such as in the imaging of individual atoms and chemical bonds, up to centimeters, such as in the imaging of coarse grain structures in metals.
Henrik Svensmark is a physicist and professor in the Division of Solar System Physics at the Danish National Space Institute in Copenhagen. He is known for his work on the hypothesis that cosmic rays are an indirect cause of global warming via cloud formation.
Nanometrology is a subfield of metrology, concerned with the science of measurement at the nanoscale level. Nanometrology has a crucial role in order to produce nanomaterials and devices with a high degree of accuracy and reliability in nanomanufacturing.
Space research is scientific study carried out in outer space, and by studying outer space. From the use of space technology to the observable universe, space research is a wide research field. Earth science, materials science, biology, medicine, and physics all apply to the space research environment. The term includes scientific payloads at any altitude from deep space to low Earth orbit, extended to include sounding rocket research in the upper atmosphere, and high-altitude balloons.
Eberhard Grün is a German planetary scientist specialized in cosmic dust research. He is an active emeritus at the Max Planck Institute for Nuclear Physics , Heidelberg (Germany), research associate at the Laboratory for Atmospheric and Space Physics (LASP) in Boulder (Colorado), and was a Professor at the University of Heidelberg until his retirement in 2007. Eberhard Grün has a leading role in international cosmic dust science since over 30 years.
Planetary science or, more rarely, planetology, is the scientific study of planets, moons, and planetary systems and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history. It is a strongly interdisciplinary field, originally growing from astronomy and earth science, but which now incorporates many disciplines, including planetary geology, cosmochemistry, atmospheric science, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology. Allied disciplines include space physics, when concerned with the effects of the Sun on the bodies of the Solar System, and astrobiology.
The Interstellar Mapping and Acceleration Probe(IMAP) is a heliophysics mission that will simultaneously investigate two important and coupled science topics in the heliosphere: the acceleration of energetic particles and interaction of the solar wind with the local interstellar medium. These science topics are coupled because particles accelerated in the inner heliosphere play crucial roles in the outer heliospheric interaction. In 2018, NASA selected a team led by David J. McComas of Princeton University to implement the mission, which is currently planned to launch in February 2025. IMAP will be a Sun-tracking spin-stabilized satellite in orbit about the Sun–Earth L1 Lagrange point with a science payload of ten instruments. IMAP will also continuously broadcast real-time in-situ data that can be used for space weather prediction.
Lindsay Erin Glesener is an assistant professor in the University of Minnesota Institute for Astrophysics. She is a National Science Foundation CAREER Award researcher and lead investigator on the FOXSI Sounding Rocket.
