Merav Opher

Last updated
Merav Opher
Alma mater University of São Paulo
Scientific career
Thesis Efeitos de plasma no universo primordial  (1998)

Merav Opher is a professor of astronomy at Boston University known for her work on the heliosphere, the cocoon formed by the wind emanated from the Sun as it travels in the Galaxy. In 2021 she was named a William Bentinck-Smith Fellow at the Harvard Radcliffe Institute.

Contents

Education and career

Opher was born in Israel and lived there until 1978 when she moved to Brazil with her parents. [1] In 1992 and 1998, Opher received her B.S. in physics and her Ph.D. in physics and astronomy from the University of São Paulo. [2] Following her Ph.D., Opher was a postdoctoral investigator at the University of California, Los Angeles from 1999 until 2001. She was a Caltech Scholar at NASA's Jet Propulsion Laboratory and at University of Michigan from 2001-2004. She was on the faculty of George Mason University from 2005 until 2010, at which point she moved to Boston University, where she was promoted to professor in 2020. [3]

Opher is the director of the SHIELD DRIVE Science Center at Boston University, a project funded by NASA that will study the shape of the heliosphere. [4] [5] She has served on the Space Studies Board at the National Academy of Sciences which evaluated the progress of space and solar physics. [6]

Research

Her research interests include computational and theoretical plasma physics in space and astrophysics, interaction of the Solar System with the interstellar medium, solar wind, and shocks in the lower corona, T-Tauri and Solar-Like Stars. [7] In 2001, Opher began work on the heliosphere while she was a postdoctoral student at the Jet Propulsion lab. [8] Her researcher focuses on how the solar wind shapes the heliosphere, the protective atmospheric shield between Earth and the rest of the galaxy, where she has shown the shape of the heliosphere is similar to a croissant and not a comet with a tail as previously thought. [9] [10] Opher's 2020 paper expanding on the crescent shape of the heliosphere was published in Nature Astronomy , featured on the cover of the July 2020 issue, [11] and covered by the media. [12] [13] In 2021, Opher's research revealed that the stability of the heliosphere originates from the neutral hydrogen particles that interact with the heliosphere. [14] [15] [16]

Opher has written in The Hill about the dangers of space tourism for people where she describes the radiation coming through space and the need to better understand how the heliosphere filters this radiation before people can travel safely to other planets. [17]

As of 2021, Opher's research has been cited more than 4400 times and she has an h-index of 37. [18]

Honors and awards

In 2008, Opher received an NSF Young Investigator Award, [7] a Presidential Early Career Award for Scientists and Engineers, [19] and she was named a Kavli Fellow by the National Academy of Sciences. [3] In 2021, Opher was named a William Bentinck-Smith Fellow at the Harvard Radcliffe Institute. [9]

Selected publications

Related Research Articles

<span class="mw-page-title-main">Magnetosphere</span> Region around an astronomical object in which its magnetic field affects charged particles

In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior dynamo.

<span class="mw-page-title-main">Sun</span> Star at the center of the Solar System

The Sun is the star at the center of the Solar System. It is a massive, hot ball of plasma, inflated and heated by energy produced by nuclear fusion reactions at its core. Part of this energy is emitted from its surface as light, ultraviolet, and infrared radiation, providing most of the energy for life on Earth. The Sun has been an object of veneration in many cultures. It has been a central subject for astronomical research since antiquity.

<span class="mw-page-title-main">Solar System</span> The Sun and objects orbiting it

The Solar System is the gravitationally bound system of the Sun and the objects that orbit it. It was formed 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc. The Sun is an ordinary star that maintains hydrostatic equilibrium by the thermonuclear fusion of hydrogen into helium at its core, releasing this energy from its photosphere.

<span class="mw-page-title-main">Solar wind</span> Stream of charged particles from the Sun

The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV. The composition of the solar wind plasma also includes a mixture of materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei of elements such as C, N, O, Ne, Mg, Si, S, and Fe. There are also rarer traces of some other nuclei and isotopes such as P, Ti, Cr, and 58Ni, 60Ni, and 62Ni. Superimposed with the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field. The boundary separating the corona from the solar wind is called the Alfvén surface.

<span class="mw-page-title-main">Outer space</span> Void between celestial bodies

Outer space is the expanse beyond celestial bodies and their atmospheres. Outer space is not completely empty; it is a near-perfect 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.

<span class="mw-page-title-main">Coronal mass ejection</span> Ejecta from the Suns corona

A coronal mass ejection (CME) is a significant ejection of magnetic field and accompanying plasma mass from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accepted theoretical understanding of these relationships has not been established.

<span class="mw-page-title-main">Plasma cosmology</span> Non-standard model of the universe; emphasizes the role of ionized gases

Plasma cosmology is a non-standard cosmology whose central postulate is that the dynamics of ionized gases and plasmas play important, if not dominant, roles in the physics of the universe at interstellar and intergalactic scales. In contrast, the current observations and models of cosmologists and astrophysicists explain the formation, development, and evolution of large-scale structures as dominated by gravity.

<span class="mw-page-title-main">Stellar atmosphere</span> Outer region of the volume of a star

The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone.

<span class="mw-page-title-main">Bow shock</span> Boundary between a magnetosphere and an ambient magnetized medium

In astrophysics, a bow shock occurs when the magnetosphere of an astrophysical object interacts with the nearby flowing ambient plasma such as the solar wind. For Earth and other magnetized planets, it is the boundary at which the speed of the stellar wind abruptly drops as a result of its approach to the magnetopause. For stars, this boundary is typically the edge of the astrosphere, where the stellar wind meets the interstellar medium.

<span class="mw-page-title-main">Heliosphere</span> Region of space dominated by the Sun

The heliosphere is the magnetosphere, astrosphere, and outermost atmospheric layer of the Sun. It takes the shape of a vast, tailed bubble-like region of space. In plasma physics terms, it is the cavity formed by the Sun in the surrounding interstellar medium. The "bubble" of the heliosphere is continuously "inflated" by plasma originating from the Sun, known as the solar wind. Outside the heliosphere, this solar plasma gives way to the interstellar plasma permeating the Milky Way. As part of the interplanetary magnetic field, the heliosphere shields the Solar System from significant amounts of cosmic ionizing radiation; uncharged gamma rays are, however, not affected. Its name was likely coined by Alexander J. Dessler, who is credited with the first use of the word in the scientific literature in 1967. The scientific study of the heliosphere is heliophysics, which includes space weather and space climate.

<span class="mw-page-title-main">Local Interstellar Cloud</span> Interstellar cloud in the Milky Way Galaxy

The Local Interstellar Cloud (LIC), also known as the Local Fluff, is an interstellar cloud roughly 30 light-years (9.2 pc) across, through which the Solar System is moving. This feature overlaps with a region around the Sun referred to as the solar neighborhood. It is unknown whether the Sun is embedded in the Local Interstellar Cloud, or is in the region where the Local Interstellar Cloud is interacting with the neighboring G-Cloud. Like the G-Cloud and others, the LIC is part of the Very Local Interstellar Medium which begins where the heliosphere and interplanetary medium end, the furthest that probes have traveled.

<span class="mw-page-title-main">Interplanetary medium</span> Material which fills the Solar System

The interplanetary medium (IPM) or interplanetary space consists of the mass and energy which fills the Solar System, and through which all the larger Solar System bodies, such as planets, dwarf planets, asteroids, and comets, move. The IPM stops at the heliopause, outside of which the interstellar medium begins. Before 1950, interplanetary space was widely considered to either be an empty vacuum, or consisting of "aether".

<span class="mw-page-title-main">Heliospheric current sheet</span> Surface of magnetic polarity change

The heliospheric current sheet, or interplanetary current sheet, is a surface separating regions of the heliosphere where the interplanetary magnetic field points toward and away from the Sun. A small electrical current with a current density of about 10−10 A/m2 flows within this surface, forming a current sheet confined to this surface. The shape of the current sheet results from the influence of the Sun's rotating magnetic field on the plasma in the interplanetary medium. The thickness of the current sheet is about 10,000 km (6,200 mi) near the orbit of the Earth.

Space physics, also known as space plasma physics, is the study of naturally occurring plasmas within Earth's upper atmosphere and the rest of the Solar System. It includes the topics of aeronomy, aurorae, planetary ionospheres and magnetospheres, radiation belts, and space weather. It also encompasses the discipline of heliophysics, which studies the solar physics of the Sun, its solar wind, the coronal heating problem, solar energetic particles, and the heliosphere.

<span class="mw-page-title-main">Heliophysics</span> Science of the heliosphere

Heliophysics is the physics of the Sun and its connection with the Solar System. NASA defines heliophysics as "(1) the comprehensive new term for the science of the Sun - Solar System Connection, (2) the exploration, discovery, and understanding of Earth's space environment, and (3) the system science that unites all of the linked phenomena in the region of the cosmos influenced by a star like our Sun."

<span class="mw-page-title-main">Energetic neutral atom</span> Technology to create global images of otherwise invisible phenomena

Energetic Neutral Atom (ENA) imaging is a technology used to create global images of otherwise invisible phenomena in the magnetospheres of planets and throughout the heliosphere.

<span class="mw-page-title-main">Pickup ion</span>

In solar physics, heliospheric pickup ions are created when neutral particles inside the heliosphere are ionized by either solar ultraviolet radiation, charge exchange with solar wind protons or electron impact ionization. Pickup ions are generally characterized by their single charge state, a typical velocity that ranges between 0 km/s and twice the solar wind velocity (~800 km/s), a composition that reflects their neutral seed population and their spatial distribution in the heliosphere. The neutral seed population of these ions can either be of interstellar origin or of lunar-, cometary, or inner-source origin. Just after the ionization, the singly charged ions are picked up by the magnetized solar wind plasma and develop strong anisotropic and toroidal velocity distribution functions, which gradually transform into a more isotropic state. After their creation, pickup ions move with the solar wind radially outwards from the Sun.

Philippa K. Browning is a Professor of Astrophysics in the Jodrell Bank Centre for Astrophysics at the University of Manchester. She specialises in the mathematical modelling of fusion plasmas.

Shensuo, formerly Interstellar Express is a proposed Chinese National Space Administration program designed to explore the heliosphere and interstellar space. The program will feature two or three space probes that will purportedly be launched in 2024 and follow differing trajectories to encounter Jupiter to assist them out of the Solar System. The first probe, IHP-1, will travel toward the nose of the heliosphere, while the second probe, IHP-2, will fly near to the tail, skimming by Neptune and Triton in January 2038. There may be another probe—tentatively IHP-3—which would launch in 2030 to explore to the northern half of the heliosphere. IHP-1 and IHP-2 would be the sixth and seventh spacecraft to leave the Solar System, as well as first non-NASA probes to achieve this status.

Antoinette (Toni) Galvin is space physicist at the University of New Hampshire. She is known for her research on the solar wind.

References

  1. ↑ Merav Opher reads "One Art" by Elizabeth Bishop (Favorite Poem Project) , retrieved 2021-12-17
  2. ↑ Opher, Merav (1998). Efeitos de plasma no universo primordial [Plasma effects in the primordial universe.] (Thesis) (in Portuguese). University of Sao Paulo. OCLC   55913904.
  3. 1 2 "Merav Opher" (PDF). BU. Retrieved 12 March 2021.
  4. ↑ "People | SHIELD DRIVE Science Center". sites.bu.edu. Retrieved 2021-12-17.
  5. ↑ Jahnke, Art (February 21, 2020). "Visualizing The Heliosphere, Our Solar System's Protective Bubble". Boston University. Retrieved 2021-12-17.
  6. ↑ Committee on the Review of Progress Toward Implementing the Decadal Survey – Solar and Space Physics: A Science for a Technological Society; Space Studies Board; Division on Engineering and Physical Sciences; National Academies of Sciences, Engineering, and Medicine (2020-06-29). Progress Toward Implementation of the 2013 Decadal Survey for Solar and Space Physics: A Midterm Assessment. Washington, D.C.: National Academies Press. doi:10.17226/25668. ISBN   978-0-309-67127-9. S2CID   241931425.{{cite book}}: CS1 maint: multiple names: authors list (link)
  7. 1 2 "Merav Opher". BU Center for Space Physics. Retrieved 12 March 2021.
  8. ↑ Laskowski, Tara (2008). "Past Pluto - The Mason Spirit - George Mason University". spirit.gmu.edu. Retrieved 2021-12-17.
  9. 1 2 "Merav Opher". Radcliffe Institute for Advanced Study at Harvard University. Retrieved 2021-12-12.
  10. ↑ Opher, M.; Drake, J. F.; Swisdak, M.; Zieger, B.; Toth, G. (2017-04-11). "The Twist of the Draped Interstellar Magnetic Field Ahead of the Heliopause: A Magnetic Reconnection Driven Rotational Discontinuity". The Astrophysical Journal. 839 (1): L12. arXiv: 1702.06178 . Bibcode:2017ApJ...839L..12O. doi: 10.3847/2041-8213/aa692f . ISSN   2041-8213. S2CID   119088337.
  11. ↑ Opher, Merav; Loeb, Abraham; Drake, James; Toth, Gabor (2020-07-01). "A small and round heliosphere suggested by magnetohydrodynamic modelling of pick-up ions". Nature Astronomy. 4 (7): 675–683. Bibcode:2020NatAs...4..675O. doi:10.1038/s41550-020-1036-0. ISSN   2397-3366. S2CID   216241125.
  12. ↑ Jean, Celia; Reich, Aaron (August 9, 2020). "Solar system's heliosphere may be croissant-shaped - study". The Jerusalem Post | JPost.com. Retrieved 2021-12-17.
  13. ↑ Crowley, James (2020-08-11). "NASA says we all live inside a giant "deflated croissant", yes really". Newsweek. Retrieved 2021-12-17.
  14. ↑ Opher, M.; Drake, J. F.; Zank, G.; Powell, E.; Shelley, W.; Kornbleuth, M.; Florinski, V.; Izmodenov, V.; Giacalone, J.; Fuselier, S.; Dialynas, K. (2021-12-01). "A Turbulent Heliosheath Driven by the Rayleigh–Taylor Instability". The Astrophysical Journal. 922 (2): 181. Bibcode:2021ApJ...922..181O. doi: 10.3847/1538-4357/ac2d2e . ISSN   0004-637X. S2CID   244797589.
  15. ↑ Reich, Aaron (December 5, 2021). "Neutral hydrogen gives solar system's heliosphere its croissant-shape". The Jerusalem Post | JPost.com. Retrieved 2021-12-17.
  16. ↑ Carleton, Audrey (December 7, 2021). "A Flaky Croissant-Shaped Bubble Surrounds Our Solar System, Scientists Say". www.vice.com. Retrieved 2021-12-17.
  17. ↑ Opher, Merav; Ayala, Christine (2021-11-27). "Health risks of space tourism: Is it responsible to send humans to Mars?". TheHill. Retrieved 2021-12-17.
  18. ↑ "merav opher". scholar.google.com. Retrieved 2021-12-12.
  19. ↑ "White House Announces 2007 Awards for Early Career Scientists and Engineers". georgewbush-whitehouse.archives.gov. Retrieved 2021-12-12.
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