Many Worlds

Author: Marc Kaufman (page 1 of 17)

The WFIRST Space Observatory Becomes the Nancy Grace Roman Space Telescope. But Will it Ever Fly?

May 26, 2020 / / 0 Comments

An artist’s rendering of NASA’s Wide Field Infrared Survey Telescope (WFIRST), now  the Nancy Grace Roman Space Telescope, which will search for exoplanets that are small rocky as well as Neptune sized at a greater distance from their host stars than currently possible.  It will also study multiple cosmic phenomena, including dark energy and other theorized Einsteinian phenomena. (NASA’s Goddard Space Flight Center)

Earlier last week, NASA put out a release alerting journalists to  “an exciting announcement about the agency’s Wide Field Infrared Survey Telescope (WFIRST) mission.”

Given the controversial history of the project — the current administration has formally proposed cancelling it for several years and the astronomy community (and Congress) have been keep it going — it seemed to be a  newsworthy event, maybe a breakthrough regarding an on-again, off-again very high profile project.

And since WFIRST was the top large mission priority of the National Academies of Sciences some years ago — guidance that NASA almost always follows — the story could reflect some change in the administration’s approach to the value of long-established scientific norms.  Plus, it could mean that a space observatory with cutting-edge technology for identifying and studying exoplanets and for learning much more about dark matter and Einsteinian astrophysics might actually be launched in the 2020s.

But instead of a newsy announcement about fate of the space telescope, what NASA disclosed was that the project had been given a new name — the Nancy Grace Roman space telescope.

As one of NASA’S earliest hired and highest-ranking women, Roman spent 21 years at NASA developing and launching space-based observatories that studied the sun, deep space, and Earth’s atmosphere. She most famously worked to develop the concepts behind the Hubble Space Telescope, which just spent its 30th year in orbit.

This is a welcome and no doubt deserving honor.  But it will be much less of an honor if the space telescope is never launched into orbit.  And insights into the fate of WFIRST (the Nancy Grace Roman Space Telescope) are what really would constitute “an exciting announcement.”

What’s going on?

Nancy Grace Roman at NASA’s Goddard Space Flight Centre in the early 1970s (NASA)

 

I have no special insights, but I think that one of the scientists on the NASA Science Live event was probably on to something when she said:

“I find it tremendously exciting that the observatory is being  renamed,”  said Julie McEnery, deputy project scientist for the (now) NASA Roman mission.  … Read more

Mapping the Surfaces of Our Solar System

May 4, 2020 / / 0 Comments

 

A portion of the new “unified” geological map of the moon. (NASA/GSFC/USGS.)

It was not all that long ago that a “map” of our  moon, of Mars, of a large asteroid such as Vesta, of Titan, or of any hard-surfaced object in our solar system would have some very general outlines, some very large features identified,  and  then the extraterrestrial equivalent of the warning on Earth maps of yore that beyond a certain point “there be dragons.”  Constructing a map of the topography and geology of a distant surface requires deep understanding and data and lot of hard work.

Yet such an in-depth mapping is underway and has already resulted in detailed surface rendering of Mars,  of Jupiter’s moons Ganymede and Io, and of our moon.  And now, using both Apollo-era data for the moon and measurements from the Japanese lunar orbiter and currently flying American orbiter, the U.S. Geological Survey, in partnership with NASA and the Lunar and Planetary Institute,  has produced a rendering of our moon that moves extraterrestrial mapping significantly further.

It unifies all the data collected using a variety of techniques and produces a map with well-defined geological units, with in-laid topography (on digital versions,) and with a guide of sorts for moon watchers on Earth.  The red sections in the map above are the basalt lava flows that have the fewest craters from asteroid hits and so are the youngest surfaces.  They are also the darker sections of the moon that we see when we look into the night sky at a full moon.

The maps are not at a detail to allow NASA mission planners to assess a landing site, but they do tell what the geological environs are going to be and so are a guide to what might be found.

 

Orthographic projections (presenting three-dimensional objects in two-dimensions)  of the new “Unified Geologic Map of the Moon” showing the geology of the moon’s near side (left) and far side (right) with shaded topography from the Lunar Orbiter Laser Altimeter (LOLA). This geologic map is a synthesis of six Apollo-era regional geologic maps, updated based on data from recent satellite missions. It will serve as a reference for lunar science and future human missions to the Moon.  (NASA/GSFC/USGS.)

The chief purpose of the map — in which 5 kilometers of distance are represented by 1 millimeter on the map — is to summarize the current state of lunar geologic knowledge.… Read more

Viruses, the Virosphere and Astrovirology

April 17, 2020 / / 0 Comments

An electron microscopic image of the 2019 novel coronavirus grown in cells at The University of Hong Kong.  Thin-section electron micrographs of the novel coronavirus show part of an infected cell, grown in a culture, with virus particles being released from the cell’s surface. (The University of Hong Kong)

 

When the word “virus” first came into use, it was as a “poison” and “a very small disease-causing agent.”  While the presence of viruses was theorized earlier, they were not fully identified until the 1890s.

So from their earliest discovery, viruses were synonymous with disease and generally of the ghastly epidemic type of disease we now see with coronavirus.  Few words carry such a negative punch.

Without in any way  minimizing the toll of viruses on humans (and apparently all other living things,) men and women who study viruses know that this association with disease is far too restrictive and misses much of what viruses do.  It’s perhaps not something to argue while a viral pandemic is raging, but that’s when the focus on viruses is most intense.

Here, then, is a broader look at what viruses do and have done — how they inflict pandemics but also have introduced genes that have led to crucial evolutionary advances, that have increased the once-essential ability of cyanobacteria in early Earth oceans to photosynthesize and produce oxygen, and that have greatly enhanced the immunity systems of everything they touch.  They — and the virosphere they inhabit — have been an essential agent of change.

Viruses are also thought to be old enough to have played a role — maybe a crucial role — in the origin of life, when RNA-like replicators outside cells may have been common and not just the domain of viruses.  This is why there is a school of thought that the study of viruses is an essential part of astrobiology and the search for the origins of life.  The field is called astrovirology.

Viruses are ubiquitous — infecting every living thing on Earth.

Virologists like to give this eye-popping sense of scale:  based on measurements of viruses in a liter of sea water, they calculate the number of viruses in the oceans of Earth to be 10 31.  That is 10 with 31 zeros after it.  If those viruses could be lined up, the scientists have calculated, they would stretch across the Milky Way 100 times.

“The vast majority of viruses don’t care about humans and have nothing to do with them,” said Rika Anderson,  who studies viruses around hydrothermal vents and teaches at Carleton College in Minnesota. … Read more

April 1, 2020

Theorized Northern Ocean of Mars; now long gone.  (NASA)

Change is the one constant in our world– moving in ways tiny and enormous,  constructive and destructive.

We’re living now in a time when a rampaging pandemic circles the globe and when the climate is changing in so many worrisome and potentially devastating ways.

With these ominous  changes as a backdrop, it is perhaps useful to spend a moment with change as it happens in a natural world without humans.  And just how complete that change can be:

For years now, planetary scientists have debated whether Mars once had a large ocean across its northern hemisphere.

There certainly isn’t one now — the north of Mars is parched, frigid and largely featureless.  The hemisphere was largely covered over in a later epoch by a deep bed of lava, hiding signs of its past.

The northern lowlands of Mars, as photographed by the Viking 2 lander. The spacecraft landed in the Utopia Planitia section of northern Mars in 1976. (NASA/JPL)

Because our sun sent out significantly less warmth at the time of early Mars (4.2-3.5  billion years ago,) climate modelers have long struggled to come up with an explanation for how the planet — on average, 137 million miles further out than Earth — could have been anything but profoundly colder than today. And if that world was so unrelentingly frigid, how could there be a surface ocean of liquid water?

But discoveries in the 21st century have strongly supported the long-ago presence of water on a Mars in the form of river valleys, lakes and a water cycle to feed them.  The work done by the Curiosity rover and Mars-orbiting satellites has made this abundantly clear.

An ocean in the northern lowlands is one proposal made to explain how the water cycle was fed.

And now, In a new paper in Journal of Geophysical Research: Planets,  scientists from Japan and the United States have presented modelling and analysis describing how and why Mars had to have a large ocean early in its history to produce the geological landscape that is being found.

Lead author Ramses Ramirez, a planetary scientist with the Earth-Life Science Institute in Tokyo, said it was not possible to determine how long the ocean persisted, but their team concluded that it had to be present  in that early period around 4 billion to 3.5 billion years ago.  That is roughly when what are now known to be river valleys were cut in the planet’s southern highlands.… Read more

What, Exactly, Is A Virus?

March 23, 2020 / / 0 Comments

An illustration of the coronavirus. (Centers of Disease Control)

By now, the coronavirus is an all too familiar menace to most of the peoples of the world.  How it is spread,  the symptoms of the disease,  the absolute necessity of taking precautions against it — most people know something about the coronavirus pandemic.

But the question of what a virus actually is, what are its characteristics and where do they come from,  this seem to be far less well understood by the public.

So here is a primer on this often so destructive agent and its provenance — a look into the complicated, sometimes deadly and yes, fascinating world of viruses.

Viruses are microscopic pathogens that have genetic material (DNA or RNA molecules that encode the structure of the proteins by which the virus acts), that have a  a protein coat (which surrounds and protects the genetic material), and in some cases they have an outside envelope of lipids.

Most virus species have virions — the name given to a virus when it is not inside a host cell. They are too small to be seen with an optical microscope because they are one hundredth the size of most bacteria.

Transmission electron microscope image shows SARS-CoV-2, the virus that causes COVID-19, isolated from a patient in the U.S. Virus particles are emerging from the surface of cells cultured in the lab. The spikes on the outer edge of the virus particles give coronaviruses their name, crown-like. (NIAID-RML)

Unlike bacteria, viruses are generally not considered to be “alive.”

Although viruses do have genomes, they need to take over the machinery of other living cells to follow their own genome instructions.  This is why viruses cannot reproduce by themselves — as opposed to non-viral parasites  that can reproduce outside of a host cell.

Viruses are also too small and simple to collect and use energy, i.e., perform metabolism.   So they just take energy from the cells they infect, and use it only when they make copies of themselves.  They don’t need any energy at all when they are outside of a cell.

And viruses have no way to control their internal environment,  and so they do not maintain their own homeostasis as living creatures do.

These limitations are what lead many scientists to describe viruses as “almost alive,” which is a complicated state of existence indeed.

 

Infectious particles of an avian influenza virus emerge from a cell. 

… Read more

Planetary Protection and the Moons of Mars

March 4, 2020 / / 0 Comments

Mars with its two moons, Phobos and Deimos. Phobos orbits a mere 3,700 mile3s (6,000 km) above the surface, while Deimos is almost 15,000 miles (24,000 kilometers) away from the planet. In comparison, there is an almost 384,000 kilometers mean distance between the surface of the Earth and our elliptically orbiting moon. With the moons so close to Mars, debris from meteorite impacts on the planet can easily land on the moons. (NASA/JPL-Caltech/University of Arizona)

Sometime in the early to mid-2020s, the capsule of the Japanese Martian Moons eXploration (MMX) mission is scheduled to arrive at the moons of Mars – Phobos and Deimos.

These are small and desolate places, but one goal of the mission is large: to collect samples from the moons and bring them back to Earth.

If it succeeds, the return would likely be the first ever from Mars or its moons — since planned sample return efforts from the planet itself will be considerably more challenging and so will take longer to plan and carry out.

The Mars moon mission has the potential to bring back significant information about their host planet, the early days of our solar system, and the origins and make-up of the moons themselves.

It also has the potential, theoretically at least, to bring back Martian life, or signatures of past Martian microbial life. And similarly, it has the potential to bring Earth life to one of the moons.

Hidenori Genda, an ELSI planetary scientist with a long-lasting interest in the effects of giant planetary impacts, such as the one that formed our moon. His work has also focused on atmospheres, oceans, and life beyond Earth. (Nerissa Escanlar)

Under the general protocols of what is called “planetary protection,” this is a paramount issue and is why the Japan Aerospace Exploration Agency (JAXA) was obliged to assess the likelihood of any such biological transfers with MMX.

To make that assessment, the agency turned to a panel of experts that included planetary scientist, principal investigator, and associate professor Hidenori Genda of Tokyo’s Earth-Life Science Institute.

The panel’s report to JAXA and the journal Life Sciences in Space Research concluded that microbial biology (if it ever existed) on early Mars could have been kicked up by incoming meteorites, and subsequently traveled the relatively short distance through space to land on Phobos and Deimos.

However, the panel’s conclusions were unambiguous: the severe radiation these microbes would encounter on the way would make sure anything once living was now dead.… Read more

Exploring Our Sun Will Help Us Understand Habitability

February 20, 2020 / / 0 Comments

The surface of the sun, with each “kernel” or “cell” roughly the size of Texas. The movie is made up of images produced by the Daniel Inouye SolarTelescope in Hawaii.  Novel and even revolutionary data and images are also expected from the Parker Solar Probe (which will travel into the sun’s atmosphere, or corona) and the just launched Solar Orbiter, which will study (among many other things) the sun’s polar regions. (NSO/NSF/AURA)

 

Scientists have been  studying our sun for centuries, and at this point know an awful lot about it — the millions of degrees Fahrenheit heat that it radiates out from the corona, the tangled and essential magnetic fields that it creates, the million-miles-per-hour solar wind and the charged high-energy solar particles that can be so damaging to anything alive.

But we have now entered a time when solar science is taking a major leap forward with the deployment of three pioneering instruments that will explore the sun and its surroundings as never before.  One is a space telescopes that will get closer to the sun (by far) than any probe before, another is a probe that will make the first observations of the sun’s poles, and the third is a ground-based solar telescope that can resolve the sun in radically new ways — as seen in the image above, released last month.

Together, NASA’s Parker Solar Probe, the joint European Space Agency-NASA Solar Orbiter mission and the National Science Foundation’s Inouye Solar Telescope on Hawai’i will provide pathways to understand some of the mysteries of the sun.  They include resolving practical issues involving the dynamics  of “space weather” that can harm astronauts and telecommunications systems, and larger theoretical unknowns related to all the material that stars scatter into space and onto planets.

Some of those unresolved questions include determining how and why heat and energy flow from the sun’s inner core to the outer corona and make it so much hotter, determining the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind, the make-up and effects of solar flares and coronal mass ejections, and how and why the sun is able to create and control the heliosphere — the vast bubble of charged particles blown by the solar wind into interstellar space.

 

An illustration of Kepler2-33b, , one of the youngest exoplanets detected to date using NASA Kepler Space Telescope.

… Read more

Big News for SETI Enthusiasts

February 14, 2020 / / 1 Comment

The CHIME telescope has detected a mysterious repeating radio signal far away in the cosmos – only the second ever identified of its kind.  CHIME is the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is an interferometric radio telescope at the Dominion Radio Astrophysical Observatory in British Columbia, (Danielle Futselaar)

It has been almost 60 years now that scientists — a first a few intrepid souls and now many more — have been searching the skies for radio signals that just might be coming from other advanced, technological civilizations.  There have been some intriguing anomalies that created great interest, but nothing has to date survived further study.

But two recent developments in the this Search for Extraterrestrial Intelligence (SETI) make clear that the lack of alien signals so far has not diminished interest in the field and in the science and technology behind it.  Rather, SETI is alive and doing quite well.

A first sign is scientific and involves what are called “fast radio blasts” or FRBs — high energy pulses that are extremely short lived and, until recently, determined to be sporadic and random.  But a paper last week from a Canadian team reported a series fast radio blast from a galaxy a 500 million light-years away that appeared to be repeating about every 16 days.

The authors put forward a number of astrophysical explanations for this most unusual pattern and shied away from any kind of SETI hypothesis.  More on this later.

But the detection is the kind of radio signal anomaly that SETI scientists and enthusiasts are looking for.  And now they will also have the opportunity to search a vast new trove of data provided by Breakthrough Listen, part of the privately-funded Breakthrough Initiatives.

A sequence of 14 of the 15 fast radio bursts from FRB 121102, the first repeating fast radio burst to be identified, in 2018. The streaks across the colored energy plot are the bursts appearing at different times and different energies because of dispersion caused by 3 billion years of travel through intergalactic space. The bursts were captured in a broad bandwidth via the Breakthrough Listen backend instrument at the Green Bank Telescope. It does not repeat in patterns like the one just discovered by the Canadian team. (Berkeley News.)

At the close of a meeting of the American Association for the Advance of Science (AAAS) on Friday, the Breakthrough team announced the release nearly 2 petabytes (2 million gigabytes) of data, the second massive data dump from the four-year old Breakthrough Listen search for extraterrestrial intelligence

The data, most of it fresh from the telescope prior to detailed study by astronomers, comes from a survey of the radio spectrum between 1 and 12 gigahertz (GHz).… Read more

Tales From the Deep Earth

January 19, 2020 / / 0 Comments

Cross section of the varying layers of the Earth .  (Yuri Arcurs via Getty images)

When especially interesting new planets are discovered in the cosmos, scientists around the world begin the process of identifying their characteristics — their orbit, their mass and density,  their composition, their thermal properties and much more.  It’s all part of a drive that seems to be innate in humans to learn about the workings of the world (or worlds) around us.

This began millennia ago when our distant ancestors started to learn about the make-up and processes of Earth.   We now know enormous amounts about our planet, but I was recently introduced to a domain where our knowledge has some substantial holes.  The area of the Earth least well understood is, not surprisingly, what lies deep below us, in the mantle — the inner 2,900 kilometers (2000 miles) of the planet between the outer crust and the iron core.

The on-going exploration of this vast region — made up substances including some which cannot remain intact on the Earth’s surface — struck me as in some ways comparable to the study of exoplanets.   It’s also a realm where scientific observation is limited, but what knowledge is gained then leads through induction, deduction, modeling and exacting lab work to a gradual expansion back of our knowledge.

And in the case of some high-temperature, high-pressure minerals, this has led to a most unusual technique for identifying and naming key components of our inner planet.  Unable to reach or preserve some of the most important components of the mantle,  geochemists and other deep Earth scientists go to incoming meteorites to learn about what’s beneath (deeply beneath, that is) our feet.

With this in mind, here is a look at the discovery and recent naming of the mineral hiroseite, an unusual but quite widespread component of the very deep Earth.

 

ELSI director Kei Hirose has been honored for his pioneering work in identifying and describing components of the Earth’s lower mantle. In recognition of his work, a newly identified lower mantle mineral has been given the name of hiroseite. (Nerissa Escanlar)

 

It was two decades ago when Kei Hirose – a Japanese geochemist expert in high-pressure, deep-Earth phenomena, then at the Tokyo Institute of Technology – began researching a long-standing problem in understanding the working of the lower depths of our planet’s enormous mantle: the last 300 kilomiles above the boundary with the scalding iron core.

… Read more

Tatooine Worlds

January 13, 2020 / / 1 Comment

Science fiction has become science.  No habitable planets orbiting two suns like the fictional Tatooine have been detected so far, but more than a dozen “circumbinary planets” have been identified and many more are predicted.  Exoplanets orbiting a host star that orbits its own companion star are even more common. (Lucasfilm)

When the the first Star Wars movie came out in 1977, it featured the now-iconic two-sun, “circumbinary” planet Tatooine.  At that time astronomers didn’t really know if such solar systems existed, with more than one sun and at least one planet.

Indeed, the first extra-solar planet wasn’t detected until the early 1990s.  And the first actual circumbinary planet was detected in 2005, and it was a Jupiter-size planet orbiting a system composed of a sun-like star and a brown dwarf.  Tatooine was definitely not a Jupiter-size planet.

But since then, the presence and distribution of circumbinaries has grown to a dozen and some the planets discovered orbiting the two stars have been smaller.  The most recent discovery was announced this week and was made using the Transiting Exoplanet Survey Satellite (TESS) space telescope

The new planet, called TOI (TESS Object of Interest)-1338 b, is about 6.9 times larger than Earth. It orbits its pair of host stars every 95 days, while the stars themselves orbit each other in 15 days.

As is common with binary stars, one is more massive and much brighter than the other (5976 K and 3657 K, respectively, with our sun at  5780 K),  and as the planet orbits around it blocks some of the light from the brighter star.

This transit allows astronomers to measure the size of the planet.  The transit — as scientific luck, or skill, would have it — was first found in the TESS data by a high school student working at NASA with over the summer,  Wolf Cukier

“I was looking through the data for everything the volunteers had flagged as an eclipsing binary, a system where two stars circle around each other and from our view eclipse each other every orbit,” Cukier said. “About three days into my internship, I saw a signal from a system called TOI 1338.”

“At first I thought it was a stellar eclipse, but the timing was wrong. It turned out to be a planet.”

With all of the data available from observations past and current, planet hunting clearly isn’t the scientific Wild West that it used to be — although the results remain often eye-popping and surprising.… Read more

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