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Yamazaki A, Yamada M, Lee YJ, Watanabe S, Horinouchi T, Murakami SY, Kouyama T, Ogohara K, Imamura T, Sato TM, Yamamoto Y, Fukuhara T, Ando H, Sugiyama KI, Takagi S, Kashimura H, Ohtsuki S, Hirata N, Hashimoto GL, Suzuki M, Hirose C, Ueno M, Satoh T, Abe T, Ishii N, Nakamura M. Ultraviolet imager on Venus orbiter Akatsuki and its initial results. EARTH, PLANETS, AND SPACE : EPS 2018; 70:23. [PMID: 31983883 PMCID: PMC6954016 DOI: 10.1186/s40623-017-0772-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 12/25/2017] [Indexed: 05/28/2023]
Abstract
The ultraviolet imager (UVI) has been developed for the Akatsuki spacecraft (Venus Climate Orbiter mission). The UVI takes ultraviolet (UV) images of the solar radiation reflected by the Venusian clouds with narrow bandpass filters centered at the 283 and 365 nm wavelengths. There are absorption bands of SO2 and unknown absorbers in these wavelength regions. The UV images provide the spatial distribution of SO2 and the unknown absorber around cloud top altitudes. The images also allow us to understand the cloud top morphologies and haze properties. Nominal sequential images with 2-h intervals are used to understand the dynamics of the Venusian atmosphere by estimating the wind vectors at the cloud top altitude, as well as the mass transportation of UV absorbers. The UVI is equipped with off-axial catadioptric optics, two bandpass filters, a diffuser installed in a filter wheel moving with a step motor, and a high sensitivity charge-coupled device with UV coating. The UVI images have spatial resolutions ranging from 200 m to 86 km at sub-spacecraft points. The UVI has been kept in good condition during the extended interplanetary cruise by carefully designed operations that have maintained its temperature maintenance and avoided solar radiation damage. The images have signal-to-noise ratios of over 100 after onboard desmear processing.
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Affiliation(s)
- Atsushi Yamazaki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Manabu Yamada
- Planetary Exploration Research Center (PERC), Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 Japan
| | - Yeon Joo Lee
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
- Present Address: Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 Japan
| | - Shigeto Watanabe
- Hokkaido Information University, 59-2 Nishinopporo, Ebetsu, Hokkaido 069-8585 Japan
| | - Takeshi Horinouchi
- Faculty of Environmental Earth Science, Hokkaido University, N10W5, Sapporo, Hokkaido 060-0810 Japan
| | - Shin-ya Murakami
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
| | - Toru Kouyama
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, 2-3-26 Aomi, Koto-ku, Tokyo, 135-0064 Japan
| | - Kazunori Ogohara
- School of Engineering, University of Shiga Prefecture, 2500 Hassaka-cho, Hikone, Shiga 522-8533 Japan
| | - Takeshi Imamura
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 Japan
| | - Takao M. Sato
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
| | - Yukio Yamamoto
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
| | - Tetsuya Fukuhara
- Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501 Japan
| | - Hiroki Ando
- Faculty of Science, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto, Kyoto 603-8555 Japan
| | - Ko-ichiro Sugiyama
- Department of Information Engineering, National Institute of Technology, Matsue College, 14-4 Nishi-Ikuma, Matsue, Shimane 690-8518 Japan
| | - Seiko Takagi
- Research and Information Center, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 Japan
- Present Address: Hokkaido University, N10W5, Sapporo, Hokkaido 060-0810 Japan
| | - Hiroki Kashimura
- Department of Planetology/Center for Planetary Science, Kobe University, 7-1-48, Minamimachi, Minatojima Chuo-ku, Kobe, 650-0047 Japan
| | - Shoko Ohtsuki
- School of Commerce, Senshu University, 2-1-1 Higashimita, Tama-ku, Kawasaki, Kabagawa 214-8580 Japan
| | - Naru Hirata
- School of Computer Science and Engineering, The University of Aizu, 90 Kami-Iawase, Tsuruga, Ikki-machi, Aizu-Wakamatsu, Fukushima 965-8580 Japan
| | - George L. Hashimoto
- Department of Earth Science, Okayama University, 3-1-1 Tsushimanaka, Kita, Okayama 700-8530 Japan
| | - Makoto Suzuki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
| | - Chikako Hirose
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
| | - Munetaka Ueno
- Center for Planetary Science (CPS), Graduate School of Science, Kobe University, 7-1-48 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 Japan
| | - Takehiko Satoh
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
- Department of Space and Astronautical Science, School of Physical Sciences, SOKENDAI, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
| | - Takumi Abe
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
- Department of Space and Astronautical Science, School of Physical Sciences, SOKENDAI, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
| | - Nobuaki Ishii
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
| | - Masato Nakamura
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan
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Limaye SS, Watanabe S, Yamazaki A, Yamada M, Satoh T, Sato TM, Nakamura M, Taguchi M, Fukuhara T, Imamura T, Kouyama T, Lee YJ, Horinouchi T, Peralta J, Iwagami N, Hashimoto GL, Takagi S, Ohtsuki S, Murakami SY, Yamamoto Y, Ogohara K, Ando H, Sugiyama KI, Ishii N, Abe T, Hirose C, Suzuki M, Hirata N, Young EF, Ocampo AC. Venus looks different from day to night across wavelengths: morphology from Akatsuki multispectral images. EARTH, PLANETS, AND SPACE : EPS 2018; 70:24. [PMID: 31983884 PMCID: PMC6954018 DOI: 10.1186/s40623-018-0789-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 01/24/2018] [Indexed: 05/28/2023]
Abstract
Since insertion into orbit on December 7, 2015, the Akatsuki orbiter has returned global images of Venus from its four imaging cameras at eleven discrete wavelengths from ultraviolet (283 and 365 nm) and near infrared (0.9-2.3 µm), to the thermal infrared (8-12 µm) from a near-equatorial orbit. The Venus Express and Pioneer Venus Orbiter missions have also monitored the planet for long periods but from polar or near-polar orbits. The wavelength coverage and views of the planet also differ for all three missions. In reflected light, the images reveal features seen near the cloud tops (~ 70 km altitude), whereas in the near-infrared images of the nightside, features seen are at mid- to lower cloud levels (~ 48-60 km altitude). The dayside cloud cover imaged at the ultraviolet wavelengths shows morphologies similar to what was observed from Mariner 10, Pioneer Venus, Galileo, Venus Express and MESSENGER. The daytime images at 0.9 and 2.02 µm also reveal some interesting features which bear similarity to the ultraviolet images. The nighttime images at 1.74, 2.26 and 2.32 µm and at 8-12 µm reveal features not seen before and show new details of the nightside including narrow wavy ribbons, curved string-like features, long-scale waves, long dark streaks, isolated bright spots, sharp boundaries and even mesoscale vortices. Some features previously seen such as circum-equatorial belts (CEBs) and occasional areal brightenings at ultraviolet (seen in Venus Express observations) of the cloud cover at ultraviolet wavelengths have not been observed thus far. Evidence for the hemispheric vortex organization of the global circulation can be seen at all wavelengths on the day- and nightsides. Akatsuki images reveal new and puzzling morphology of the complex nightside cloud cover. The cloud morphologies provide some clues to the processes occurring in the atmosphere and are thus, a key diagnostic tool when quantitative dynamical analysis is not feasible due to insufficient information.
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Affiliation(s)
- Sanjay S. Limaye
- Space Science and Engineering Center, University of Wisconsin, Madison, WI 53706 USA
| | - Shigeto Watanabe
- Space Information Center, Hokkaido Information University, Ebetsu, Hokkaido 069-8585 Japan
| | - Atsushi Yamazaki
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Manabu Yamada
- Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1, Tsudanuma, Narashino, Chiba 275-0016 Japan
| | - Takehiko Satoh
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Takao M. Sato
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Masato Nakamura
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Makoto Taguchi
- College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501 Japan
| | - Tetsuya Fukuhara
- College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501 Japan
| | - Takeshi Imamura
- Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, Kiban-tou 4H7, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 Japan
| | - Toru Kouyama
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Yeon Joo Lee
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
- Present Address: Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, Kiban-tou 4E5, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 Japan
| | - Takeshi Horinouchi
- Faculty of Environmental Earth Science, Hokkaido University, N10W5, Sapporo, Hokkaido 060-0810 Japan
| | - Javier Peralta
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Naomoto Iwagami
- School of Commerce, Senshu University, 2-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8580 Japan
| | - George L. Hashimoto
- Department of Earth Sciences, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama, 700-8530 Japan
| | - Seiko Takagi
- Tokai University, Research and Information Center, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292 Japan
| | - Shoko Ohtsuki
- School of Commerce, Senshu University, 2-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8580 Japan
| | - Shin-ya Murakami
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Yukio Yamamoto
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Kazunori Ogohara
- School of Engineering, University of Shiga Prefecture, Hikone, Japan
| | - Hiroki Ando
- Faculty of Science, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto-City, 603-8555 Japan
| | - Ko-ichiro Sugiyama
- Department of Information Engineering, National Institute of Technology, Matsue College, 14-4 Nishi-Ikuma, Matsue, Shimane 690-8518 Japan
| | - Nobuaki Ishii
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Takumi Abe
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Chikako Hirose
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Makoto Suzuki
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Japan
| | - Naru Hirata
- ARC-Space, CAIST, The University of Aizu, 90 Kami-Iawase, Tsuruga, Ikki-machi, Aizu-Wakamatsu, Fukushima 965-8580 Japan
| | - Eliot F. Young
- Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302 USA
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Morris SC. Predicting what extra-terrestrials will be like: and preparing for the worst. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:555-571. [PMID: 21220280 DOI: 10.1098/rsta.2010.0276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
It is difficult to imagine evolution in alien biospheres operating in any manner other than Darwinian. Yet, it is also widely assumed that alien life-forms will be just that: strange, un-nerving and probably repulsive. There are two reasons for this view. First, it is assumed that the range of habitable environments available to extra-terrestrial life is far wider than on Earth. I suggest, however, that terrestrial life is close to the physical and chemical limits of life anywhere. Second, it is a neo-Darwinian orthodoxy that evolution lacks predictability; imagining what extra-terrestrial life would look like in any detail is a futile exercise. To the contrary, I suggest that the outcomes of evolution are remarkably predictable. This, however, leads us to consider two opposites, both of which should make our blood run cold. The first, and actually extremely unlikely, is that alien biospheres will be strikingly similar to our terrestrial equivalent and that in such biospheres intelligence will inevitably emerge. The reasons for this revolve around the ubiquity of evolutionary convergence, the determinate structure of the Tree of Life and molecular inherency. But if something like a human is an inevitability, why do I also claim that the first possibility is 'extremely unlikely'? Simply because the other possibility is actually the correct answer. Paradoxically, we and our biosphere are completely alone. So which is worse? Meeting ourselves or meeting nobody?
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Affiliation(s)
- Simon Conway Morris
- Department of Earth Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EQ, UK.
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