Space-Based Observations

Although vastly superior to ground-based observations, infrared observations from space are not completely background free. The primary source of infrared background radiation in space is refiection and emission by zodiacal dust. This is dust in our solar system that is distributed mainly in plane of the planets or zodiac. As shown in Fig. 9, there are two minima in the background radiation, one at 3 pm and another at 400 pm. 

FIGURE 9 The emission spectrum as seen from space by Leinert et al. The O2 and OH airglow are terrestrial emissions and are not seen from space. 

Source From Leinert, Ch. etal. Astron. Astrophys. Suppl. 127,1 (1998). 

Although there have been few space infrared missions, the missions carried out to date have proved quite successful. Due to the advantages of space infrared observations, there are also several missions in the planning stage. We will review a few of the major missions here. 

The IRAS was the first orbital space mission devoted solely to observations at infrared wavelengths. The advantage of space observation are clearly demonstrated by noting that IRAS, with a diameter of only 60 cm, vastly outperformed ground-based observations with even the 5-m Mt. Palomar observatory, the largest major observatory at the time. IRAS, launched January 1983, surveyed the sky for a little less than a year. Observations of approximately 96% of the sky were made in broad photometric bands at 12,25,60 and 100 /xm, with an array of discrete Ge detectors. Its nearly polar orbit meant that in the survey mode it covered the sky in strips that overlapped at the equator 

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How can weather forecast duration and reliability be improved by new space-based observations, data assimilation, and modeling ... 

Tiny solid cosmic particles - often referred to as dust - are the ultimate source of solids from which rocky planets, planetesimals, moons, and everything on them form. The study of the dust particles genesis and their evolution from interstellar space through protoplanetary disks into forming planetesimals provides us with a bottom-up picture on planet formation. These studies are essential to understand what determines the bulk composition of rocky planets and, ultimately, to decipher the formation history of the Solar System. Dust in many astrophysical settings is readily observable and recent ground- and space-based observations have transformed our understanding on the physics and chemistry of these tiny particles. 

Martin, R. V, D. I Jacob, K. Chance, T. R Kurosu, P. I. Palmer, and M. J. Evans (2003) Global inventory of nitrogen oxide emissions constrained by space-based observations of NO2 columns. Journal of Geophysical Research 108, 4537, doi 10.1029/2003JD003453... 

Supermolecular absorption determines significant features of the atmospheres of the planets and their large moons, such as the vertical temperature profile and the high-altitude haze distribution, and offers opportunities for the determination of abundance ratios of helium and hydrogen, ortho- and para-H2, etc. [390, 396]. In certain spectral bands the spectra may sometimes be obtained by Earth-based observations. More commonly, the spectra will be obtained in space missions, such as IRIS of Voyager I and II future missions (Infrared Space Observatory) will doubtlessly enhance the available information significantly. 

There has been a growing interest in the food industry for a color space based on a polar model. In 1976 when CIELAB was adopted, the CIE recommended an alternative color scale known as CIELCH or L C H. Of the three dimensions of color, the hue is the most critical in terms of perceptibility and acceptability for normal color observers. The L C H color space identifies the hue as one of the three dimensions. A color is located using cylindrical coordinates with L being the same as in CIELAB and C and H computed from a and b. The coordinates of CIELCH (also see Fig. F5.1.11) are ... 

S02 was first retrieved from space-based measurements using TOMS data (Krueger, 1983 Krueger et d., 1995 1996). Successful observations have been made on... 

Why use X-rays for cluster studies since they are relatively difficult to observe and require space-based observatories As clusters provide a unique window on the Universe, X-ray observations provide a unique window on clusters. 

The research of Roy Jackson combines theory and experiment in a distinctive fashion. First, the theory incorporates, in a simple manner, inertial collisions through relations based on kinetic theory, contact friction via the classical treatment of Coulomb, and, in some cases, momentum exchange with the gas. The critical feature is a conservation equation for the pseudo-thermal temperature, the microscopic variable characterizing the state of the particle phase. Second, each of the basic flows relevant to processes or laboratory tests, such as plane shear, chutes, standpipes, hoppers, and transport lines, is addressed and the flow regimes and multiple steady states arising from the nonlinearities (Fig. 6) are explored in detail. Third, the experiments are scaled to explore appropriate ranges of parameter space and observe the multiple steady states (Fig. 7). One of the more striking results is the... 

Abstract In this chapter we review recent advances in our understanding of the chemical and isotopic evolution of protoplanetary disks and the solar nebula. Current observational and meteoritic constraints on physical conditions and chemical composition of gas and dust in these systems are presented. A variety of chemical and photochemical processes that occur in planet-forming zones and beyond, both in the gas phase and on grain surfaces, are overviewed. The discussion is based upon radio-interferometric, meteoritic, space-borne, and laboratory-based observations, measurements and theories. Linkage between cosmochemical and astrochemical data are presented, and interesting research puzzles are discussed. 

Fig. 12. View of the intermolecular S S interactions in (ET)2Br04. The top figure indicates the interstack S S contact distances less than the van der Waals sum of 3.60 A (298/125 K) d, = 3.581(2)/3.505(2), d2 = 3.499(2)/3.448(2), d3 = 3.583(2)/3.483(2), d4 = 3.628(2)/3.550(2), d5 = 3.466(2)/3.402(2), d6 = 3.497(2)/3.450(2), d7 = 3.516(2)/3.434(2), and d8 = 3.475(2)/3.427(2) A. The S S contact distances, d9-d16 (bottom), are, by contrast, all longer than 3.60 A even at 125 K. In addition the loose zig-zag molecular packing of ET molecules is such that they are not equally spaced, D, = 4.01/3.95 A and D2 = 3.69/3.60 A. As a result of the (apparently) weak intrastack and strong interstack interactions, (ET)2X molecular metals are structurally different from the previously discovered (TMTSF)2X based organic superconductors. Almost identical S S distances and interplanar spacings are observed in (ET)2Re04 at both 298 and 125 K. Only theoretical calculations will reveal the extent, if any, of chemical bonding associated with the various S S distances observed in (ET) X systems.

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