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Iván Almár

Eötvös Loránd University, Astronomy, Emeritus

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I am a Hungarian astronomer involved in space research since 1958. Researcher, now researcher emeritus of the Hungarian Academy of Sciences, honorary professor of the L. Eötvös University, Budapest. Honorary member of the International Academy of Astronautics. Interested in SETI, in models of the upper-atmosphere, in satellite geodesy etc.
Address: Hungary

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Jayjit Majumdar

University of Kalyani

Jorge Castillo-Sepúlveda

Universidad de Santiago de Chile

Kansas State University

Armando Marques-Guedes

UNL - New University of Lisbon

University of Aberdeen

Mariafelicia De Laurentis

Università degli Studi di Napoli "Federico II"

University of Pretoria

Homi Bhabha National Institute (HBNI, BARC, MUMBAI)

University of Groningen

Lund University

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Papers by Iván Almár

Atmospheric Effects on Earth Satellites

Dynamical Astronomy, 1985

The Benefit of the London Scale for Astrobiology

Journal of Astrobiology & Outreach, 2018

Una determinazione della densita' dell'alta atmosfera usando il programma

Outreach Activity in Astrobiology: Illusions and Overstatements

Journal of Astrobiology & Outreach, 2014

Old and New from SETI: a Review

Proceedings of Frontier Research in Astrophysics — PoS(FRAPWS2014), May 10, 2016

This brief review of 55 years of SETI (Search for Extraterrestrial Intelligence) is intended to e... more This brief review of 55 years of SETI (Search for Extraterrestrial Intelligence) is intended to emphasize the recent paradigm change both in search strategy and in philosophy. The almost monopolistic situation of microwave radio searches after interstellar messages (old SETI) gave place to a much more diversified variety of methods and goals (new SETI). There is no positive result yet, but the tendency is promising

Investigation and modelling of an improved geomagnetic term for the CIRA'86 model at low latitudes

Advances in Space Research, 1996

Total density data based on CACTUS microaccelerometer measurements-carried out between 230 and 70... more Total density data based on CACTUS microaccelerometer measurements-carried out between 230 and 700 km altitudes at low latitudes in the period 1975-79-have been compared to corresponding MSIS'86 = CIRA'86 model values. A Dst dependent geomagnetic term is presented with height dependent term in the generalisation of the dependent coefficients (hMSIS) to replace the inadequate Kp otherwise unchanged model. This new geomagnetic term is the previously published function to altitudes below 400 km.

On the possibility of revealing irregular oscillations in the upper atmosphere

Byull. Stantsij Optichesk. Nablyud. Iskusstv. Sputnikov Zemli, 1971

Photoelectric Observations of Nova Her 1963

CoKon, 1966

Rotational Velocity of RS (23) Sextantis

On a Broader Concept of Circumstellar Habitable Zones

International Astronomical Union Colloquium, 1997

We suggest the possibility of a broader circumstellar habitable zone than considered so far. The ... more We suggest the possibility of a broader circumstellar habitable zone than considered so far. The factors taken into account – in addition to greenhouse effect – are tidal heating, and the role of ammonia (A) as a possible solvent instead of water (W) for biogenic materials. These factors can push the outer limit of the circumstellar habitable zones even further from their central stars.

A felsőlégköri geomágneses effektus összintenzitásának vizsgálata

Élet az Univerzumban: szabály vagy kivétel? | Life in the Universe: Rule or Exception?

Ivan Almar, professor of astronomy, examined the question: Life in the Universe – rule or excepti... more Ivan Almar, professor of astronomy, examined the question: Life in the Universe – rule or exception? On Earth, life was present almost since the very beginning, and, after billions of years, it has reached intelligence and technical civilization. Is this a possible route for other celestial bodies, or is it the result of an accidental chain of events that is highly unlikely to be repeated, making our Earth a rare, single exception in a lifeless Universe? Or is this the rule and the route of development for hundreds of billions of stars in the galaxies? Laws of mathematics, physics and chemistry are generally valid in the whole of the Universe, but is it also the case for laws of biology – as biology is based on the only known form of life, the life on Earth. Would we recognize alien life if we encountered it? Is there a future for life in the Universe, if it is limited to this single and fragile celestial body: Earth?

Observational results hinting at the coupling of the thermosphere with the ionosphere/magnetosphere system and with the middle atmosphere

Advances in Space Research, 1996

ABSTRACT Total density data based on CACTUS microaccelerometer measurements have been analysed be... more ABSTRACT Total density data based on CACTUS microaccelerometer measurements have been analysed between 220 and 700 km altitudes at low latitudes in the time interval 1975–79. Instantaneous residual density values with respect to atmospheric models for quiet as well as for disturbed days have been investigated as a function of local solar time (LST). It has been found that the density residuals present conspicuous increases of the variance in several LST intervals as well as a general broadening which can be in connection with various coupling mechanisms between the thermosphere and the ionosphere/magnetosphere on the one hand, and the middle atmosphere on the other. An attempt is made to select those mechanisms responsible for the observed features.

Space-VLBI: a new possibility to complement terrestrial microwave surveys

Acta Astronautica, 1998

ABSTRACT

Recommendations from the Ad Hoc Committee on SETI Nomenclature

arXiv: Popular Physics, 2018

The Ad Hoc Committee on SETI Nomenclature was convened at the suggestion of Frank Drake after the... more The Ad Hoc Committee on SETI Nomenclature was convened at the suggestion of Frank Drake after the Decoding Alien Intelligence Workshop at the SETI Institute in March 2018. The purpose of the committee was to recommend standardized definitions for terms, especially those that are used inconsistently in the literature and the scientific community. The committee sought to recommend definitions and terms that are a compromise among several desirable but occasionally inconsistent properties for such terms: 1) Consistency with the historical literature and common use in the field; 2) Consistency with the present literature and common use in the field; 3) Precision of meaning; 4) Consistency with the natural (i.e. everyday, non-jargon) meanings of terms; 5) Compatibility with non-English terms and definitions. The definitions in this report are restricted to technical, SETI contexts, where they may have jargon senses different from their everyday senses. In many cases we include terms only...

Commission 51: Bioastronomy: Search for Extraterrestrial Life

Reports on Astronomy, 1997

The past three years have been extraordinarily productive for the Bioastronomy community. In part... more The past three years have been extraordinarily productive for the Bioastronomy community. In particular, the detection of extrasolar planets and the possible evidence for fossil life on Mars have given substance to the concept of life elsewhere in the universe, and reinforced the connection between life on Earth and its cosmic origin. The structure of this report follows the agenda from the highly successful IAU Colloquium 161 on Bioastronomy, organized by Cristiano Cosmovici and Stuart Bowyer on the island of Capri in July 1996. The content has been provided by attendees of that Colloquium. Given the breadth of the subject matter covered by this Commission, this report could not have been generated any other way, and I am most grateful to all the contributors.

Rio 2.0: revising the Rio scale for SETI detections

International Journal of Astrobiology, 2018

The Rio scale is a tool for communicating the significance of a signal to the general public. It ... more The Rio scale is a tool for communicating the significance of a signal to the general public. It assigns scores to signals detected in searches for extraterrestrial intelligence (SETI), which characterizes both the consequences of a signal and the probability the signal is truly from ETI, in an easily digestible format for laypeople to interpret. In the 17 years since its construction, the number of groups actively conducting searches for evidence of intelligent life beyond the Earth has increased significantly, and theoretical work has established a new suite of observables that are capable of revealing the presence of ETI in a range of astronomical observations. In this paper, we revise the Rio scale, with the aim of (i) achieving consensus across academic disciplines on a scheme for classifying signals potentially indicating the existence of advanced extraterrestrial life, (ii) supplying a pedagogical tool to help inform the public about the process scientists go through to devel...

Comparison of the surface grooves on gaspra and phobos

Advances in Space Research, 2001

The influence of leader's spiritual values of servant leadership on employee motivational autonom... more

Investigation of the density wave activity in the thermosphere above 220 km

Advances in Space Research, 1997

Based on CACTUS (Capteur Accelerometrique Capacitif Triaxial Ultra Sensible) microaccelerometer m... more Based on CACTUS (Capteur Accelerometrique Capacitif Triaxial Ultra Sensible) microaccelerometer measurements it has been demonstrated that-after taking into account all effects included in the MSIS%=CIRA'86 &XW'AR. 1988) model-there are residual fluctuations in the density of the upper atmosphere much larger than that the accuracy of the measurements can account for. These fluctuations are attributed to some kind of wave activity fIll&Almdr, 1993, IlIPs-Alm& et al. 1996a). The average deviations from a model are considered as a measure of the amplitude of the waves in the atmosphere and are anaiysed as a function of geomagnetic coordinates. altitude and tocal solar time, in order to identify possible wave sources either in the lower lying atmosphere or in the thermosphere/ionosphere system. As a first step, the present investigation intends to make a map of the wave pattern by this method.

A proposal to improve the CIRA '86 model in the equatorial region: the ddMSIS model

Advances in Space Research, 2004

... Space Res. 13, p. 185. Abstract | PDF (1015 K) | View Record in Scopus | Cited By in Scopus (... more

Atmospheric Effects on Earth Satellites

Dynamical Astronomy, 1985

The Benefit of the London Scale for Astrobiology

Journal of Astrobiology & Outreach, 2018

Una determinazione della densita' dell'alta atmosfera usando il programma

Outreach Activity in Astrobiology: Illusions and Overstatements

Journal of Astrobiology & Outreach, 2014

Old and New from SETI: a Review

Proceedings of Frontier Research in Astrophysics — PoS(FRAPWS2014), May 10, 2016

This brief review of 55 years of SETI (Search for Extraterrestrial Intelligence) is intended to e... more This brief review of 55 years of SETI (Search for Extraterrestrial Intelligence) is intended to emphasize the recent paradigm change both in search strategy and in philosophy. The almost monopolistic situation of microwave radio searches after interstellar messages (old SETI) gave place to a much more diversified variety of methods and goals (new SETI). There is no positive result yet, but the tendency is promising

Investigation and modelling of an improved geomagnetic term for the CIRA'86 model at low latitudes

Advances in Space Research, 1996

Total density data based on CACTUS microaccelerometer measurements-carried out between 230 and 70... more Total density data based on CACTUS microaccelerometer measurements-carried out between 230 and 700 km altitudes at low latitudes in the period 1975-79-have been compared to corresponding MSIS'86 = CIRA'86 model values. A Dst dependent geomagnetic term is presented with height dependent term in the generalisation of the dependent coefficients (hMSIS) to replace the inadequate Kp otherwise unchanged model. This new geomagnetic term is the previously published function to altitudes below 400 km.

On the possibility of revealing irregular oscillations in the upper atmosphere

Byull. Stantsij Optichesk. Nablyud. Iskusstv. Sputnikov Zemli, 1971

Photoelectric Observations of Nova Her 1963

CoKon, 1966

Rotational Velocity of RS (23) Sextantis

On a Broader Concept of Circumstellar Habitable Zones

International Astronomical Union Colloquium, 1997

We suggest the possibility of a broader circumstellar habitable zone than considered so far. The ... more We suggest the possibility of a broader circumstellar habitable zone than considered so far. The factors taken into account – in addition to greenhouse effect – are tidal heating, and the role of ammonia (A) as a possible solvent instead of water (W) for biogenic materials. These factors can push the outer limit of the circumstellar habitable zones even further from their central stars.

A felsőlégköri geomágneses effektus összintenzitásának vizsgálata

Élet az Univerzumban: szabály vagy kivétel? | Life in the Universe: Rule or Exception?

Ivan Almar, professor of astronomy, examined the question: Life in the Universe – rule or excepti... more Ivan Almar, professor of astronomy, examined the question: Life in the Universe – rule or exception? On Earth, life was present almost since the very beginning, and, after billions of years, it has reached intelligence and technical civilization. Is this a possible route for other celestial bodies, or is it the result of an accidental chain of events that is highly unlikely to be repeated, making our Earth a rare, single exception in a lifeless Universe? Or is this the rule and the route of development for hundreds of billions of stars in the galaxies? Laws of mathematics, physics and chemistry are generally valid in the whole of the Universe, but is it also the case for laws of biology – as biology is based on the only known form of life, the life on Earth. Would we recognize alien life if we encountered it? Is there a future for life in the Universe, if it is limited to this single and fragile celestial body: Earth?

Observational results hinting at the coupling of the thermosphere with the ionosphere/magnetosphere system and with the middle atmosphere

Advances in Space Research, 1996

ABSTRACT Total density data based on CACTUS microaccelerometer measurements have been analysed be... more ABSTRACT Total density data based on CACTUS microaccelerometer measurements have been analysed between 220 and 700 km altitudes at low latitudes in the time interval 1975–79. Instantaneous residual density values with respect to atmospheric models for quiet as well as for disturbed days have been investigated as a function of local solar time (LST). It has been found that the density residuals present conspicuous increases of the variance in several LST intervals as well as a general broadening which can be in connection with various coupling mechanisms between the thermosphere and the ionosphere/magnetosphere on the one hand, and the middle atmosphere on the other. An attempt is made to select those mechanisms responsible for the observed features.

Space-VLBI: a new possibility to complement terrestrial microwave surveys

Acta Astronautica, 1998

ABSTRACT

Recommendations from the Ad Hoc Committee on SETI Nomenclature

arXiv: Popular Physics, 2018

The Ad Hoc Committee on SETI Nomenclature was convened at the suggestion of Frank Drake after the... more The Ad Hoc Committee on SETI Nomenclature was convened at the suggestion of Frank Drake after the Decoding Alien Intelligence Workshop at the SETI Institute in March 2018. The purpose of the committee was to recommend standardized definitions for terms, especially those that are used inconsistently in the literature and the scientific community. The committee sought to recommend definitions and terms that are a compromise among several desirable but occasionally inconsistent properties for such terms: 1) Consistency with the historical literature and common use in the field; 2) Consistency with the present literature and common use in the field; 3) Precision of meaning; 4) Consistency with the natural (i.e. everyday, non-jargon) meanings of terms; 5) Compatibility with non-English terms and definitions. The definitions in this report are restricted to technical, SETI contexts, where they may have jargon senses different from their everyday senses. In many cases we include terms only...

Commission 51: Bioastronomy: Search for Extraterrestrial Life

Reports on Astronomy, 1997

The past three years have been extraordinarily productive for the Bioastronomy community. In part... more The past three years have been extraordinarily productive for the Bioastronomy community. In particular, the detection of extrasolar planets and the possible evidence for fossil life on Mars have given substance to the concept of life elsewhere in the universe, and reinforced the connection between life on Earth and its cosmic origin. The structure of this report follows the agenda from the highly successful IAU Colloquium 161 on Bioastronomy, organized by Cristiano Cosmovici and Stuart Bowyer on the island of Capri in July 1996. The content has been provided by attendees of that Colloquium. Given the breadth of the subject matter covered by this Commission, this report could not have been generated any other way, and I am most grateful to all the contributors.

Rio 2.0: revising the Rio scale for SETI detections

International Journal of Astrobiology, 2018

The Rio scale is a tool for communicating the significance of a signal to the general public. It ... more The Rio scale is a tool for communicating the significance of a signal to the general public. It assigns scores to signals detected in searches for extraterrestrial intelligence (SETI), which characterizes both the consequences of a signal and the probability the signal is truly from ETI, in an easily digestible format for laypeople to interpret. In the 17 years since its construction, the number of groups actively conducting searches for evidence of intelligent life beyond the Earth has increased significantly, and theoretical work has established a new suite of observables that are capable of revealing the presence of ETI in a range of astronomical observations. In this paper, we revise the Rio scale, with the aim of (i) achieving consensus across academic disciplines on a scheme for classifying signals potentially indicating the existence of advanced extraterrestrial life, (ii) supplying a pedagogical tool to help inform the public about the process scientists go through to devel...

Comparison of the surface grooves on gaspra and phobos

Advances in Space Research, 2001

The influence of leader's spiritual values of servant leadership on employee motivational autonom... more

Investigation of the density wave activity in the thermosphere above 220 km

Advances in Space Research, 1997

Based on CACTUS (Capteur Accelerometrique Capacitif Triaxial Ultra Sensible) microaccelerometer m... more Based on CACTUS (Capteur Accelerometrique Capacitif Triaxial Ultra Sensible) microaccelerometer measurements it has been demonstrated that-after taking into account all effects included in the MSIS%=CIRA'86 &XW'AR. 1988) model-there are residual fluctuations in the density of the upper atmosphere much larger than that the accuracy of the measurements can account for. These fluctuations are attributed to some kind of wave activity fIll&Almdr, 1993, IlIPs-Alm& et al. 1996a). The average deviations from a model are considered as a measure of the amplitude of the waves in the atmosphere and are anaiysed as a function of geomagnetic coordinates. altitude and tocal solar time, in order to identify possible wave sources either in the lower lying atmosphere or in the thermosphere/ionosphere system. As a first step, the present investigation intends to make a map of the wave pattern by this method.

A proposal to improve the CIRA '86 model in the equatorial region: the ddMSIS model

Advances in Space Research, 2004

... Space Res. 13, p. 185. Abstract | PDF (1015 K) | View Record in Scopus | Cited By in Scopus (... more