Close and Tranquil Solar System Has Astronomers Excited

An artist’s impression of the GJ 887 planetary system of super Earths. (Mark Garlick)

From the perspective of planet hunters and planet characterizers,  a desirable solar system to explore is one that is close to ours, that has a planet (or planets) in the star’s habitable zone,  and has a host star that is relatively quiet.  This is especially important with the very common red dwarf stars,  which are far less luminous than stars such as our sun but tend to send out many more powerful — and potentially planet sterilizing — solar flares.

The prolific members of the mostly European and Chilean Red Dots astronomy team believe they have found such a system about 11 light years away from us.  The system — GJ 887 — has an unusually quiet red dwarf host, has two planets for sure and another likely that orbits at a life-friendly 50-day orbit.  It is the 12th closest planetary system to our sun.

It is that potential third planet, which has shown up in some observations but not others, that would be of great interest.  Because it is so (relatively) close to Earth, it would be a planet where the chemical and thermal make-up of its atmosphere would likely be possible to measure.

The Red Dots team — which was responsible for the first detection of a planet orbiting Proxima Centauri and also Barnard’s star — describes the system in an article in the journal Science.  Team leader Sandra Jeffers of Goettingen University in Germany said in an email that GJ 887  “will be an ideal target because it is such a quiet star — no starspots or energetic outbursts  or flares.”

In an accompanying Perspective article in Science,  Melvyn Davies of Lund University in Sweden wrote that “If further observations confirm the presence of the third planet in the habitable zone, then GJ 887 could become one of the most studied planetary systems in the solar neighborhood.”

An artist’s impression of a flaring red dwarf star and a nearby planet. Red dwarfs are by far the most common stars in the sky, and most have planetary systems.  But scientists are unsure if they can support a habitable planet because many send out more large and powerful flares than other types of stars, especially at the beginnings of their solar lives. (Roberto Molar Candanosa/Carnegie/NASA)

GJ 877 is roughly half as massive as our sun — large for its type of star — and is the brightest red dwarf in the sky.… Read more

Thinking About Life (or Lyfe) Through The Prism of “Star Trek”

This column was written for Many Worlds by Michael L. Wong and Stuart Bartlett.  Wong is a postdoctoral research associate at the University of Washington’s Astronomy and Astrobiology program and is a member of  NASA’s Nexus for Exoplanet System Science (NExSS) initiative as part of the university’s Virtual Planetary Laboratory team.  Bartlett is a postdoctoral scholar in Geochemistry at the California Institute of Technology and has been a fellow at the Earth-Live Science Institute (ELSI) in Tokyo.

 

Spock communicates with a Horta,  a fictional silicon-based life form composed of molten rock and acid.  (Star Trek; CBS Studios)

By Michael L. Wong and Stuart Bartlett

 

The search for extraterrestrial life is in its early phase still  and, the truth is, we don’t yet know if life exists beyond our pale blue dot.  Or, if it does, whether it will be easily recognizable or truly bizarre.

Predicting what might be out there, and how to find it, is a hypothesis-driven area of research at present — one that has given rise to hundreds of possible definitions for the “life” we are looking for.

But after grounding ourselves in scientific principles, it may be that our greatest tool is to let our imaginations fly. Science fiction often helps us embrace our ignorance of what might be out there.

In the Star Trek universe, our galaxy is teeming with life—both astonishingly familiar and incredibly different.

The familiar variety includes Mr. Spock, the U.S.S. Enterprise’s half-human, half-Vulcan science officer. He is the product of an extraordinary cosmic coincidence: the emergence of nearly identical biochemical machinery on two completely separate worlds. Vulcans—despite their pointy ears, upswept eyebrows, and a nearly religious devotion to bowl cuts—are incredibly similar to humans on the cellular, genetic, and metabolic level.

We can share meals, share air, and, yes, share intimacy. Even their green, copper-based blood is not as alien as it might seem; this trait is typical of most mollusks and crustaceans on Earth.

 

The Crystalline entity was a powerful, spaceborne creature characterized by a crystalline structure that resembled a large snowflake. (Star Trek;  CBS Studios)

But Star Trek also depicts life forms that are incredibly dissimilar from you, me, or Mr. Spock.

Take the Horta, for example. This lumpy mass, like a misshapen meatball crossed with a child’s volcano science experiment, is a silicon-based life form composed of molten rock and acid.

Then there’s Q, a non-corporeal being that possesses god-like powers which, it seems, are directed solely upon harassing Captain Jean-Luc Picard.… Read more

For First Time, Tiny CubeSat Locates a Distant Exoplanet

 

The image above, courtesy of NASA’s Jet Propulsion Laboratory, shows the CubeSat ASTERIA as it was being launched from the International Space Station in 2017.

The size of a briefcase, ASTERIA is part of a growing armada of tiny spacecraft being launched around the world and adding an increasingly important (and inexpensive) set of new tools for conducting Earth, space and exoplanet science.

ASTERIA, for instance, was designed to perform some of the complex tasks much larger space observatories use to study distant exoplanets outside our solar system.   And a new paper soon to be published in the Astronomical Journal describes how ASTERIA (short for Arcsecond Space Telescope Enabling Research in Astrophysics) didn’t just demonstrate it could perform those tasks but went above and beyond, detecting the known exoplanet 55 Cancri e.

While it was not the first detection of that exoplanet — which orbits close to its host star 41 light years away — it was the first time that a CubeSat had measured the presence of an exoplanet, something done so far only by much more sophisticated space and ground telescopes.

“Detecting this exoplanet is exciting because it shows how these new technologies come together in a real application,” said Vanessa Bailey, who led the ASTERIA  exoplanet science team at JPL.  The project was a collaboration between JPL and the Massachusetts Institute of Technology.

“We went after a hard target with a small telescope that was not even optimized to make science detections – and we got it, even if just barely,” said Mary Knapp, the ASTERIA project scientist at MIT’s Haystack Observatory and lead author of the study. “I think this paper validates the concept that motivated the ASTERIA mission: that small spacecraft can contribute something to astrophysics and astronomy.”  Both made their comments in a JPL release.

 

Artist rendering of planet Cancri 55 e. (NASA; JPL/Caltech)

 

ASTERIA was originally designed to spend 90 days in space.  But it received three mission extensions before the team lost contact with the satellite in late 2019.

The mission was not even designed to look for exoplanets.  It was, rather, a technology demonstration, with the mission’s goal to develop new capabilities for future missions. The team’s technological leap was to build a small spacecraft that could conduct fine pointing control — essentially the ability to stay focused very steadily on a distant star for long periods.… Read more

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

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

Standing on an Asteroid: Could the Future of Research and Education be Virtual Reality?

Scenes from the virtual reality talk on Hayabusa2 with students from the Yokohama International School. Each student has a robot avatar they can use to look around the scene, talk with other people and interact with objects. (OmniScope)

Have you ever wondered what it would be like to stand on an asteroid? A rugged terrain of boulders and craters beneath your feed, while the airless sky above you opens onto the star-spangled blackness of space.

It sounds like the opening scene for a science fiction movie. But this month, I met with students on the surface of an asteroid, all without leaving my living room.

The solution to this riddle —as you probably guessed from the title of this article— is virtual reality.

Virtual reality (or VR) allows you to enter a simulated environment. Unlike an image or even a video, VR allows you to look in all directions, move freely and interact with objects to create an immersive experience. An appropriate analogy would be to imagine yourself imported into a computer game.

It is therefore perhaps not surprise that a major application for VR has been the gaming industry. However, interest has recently grown in educational, research and training applications.

Discussing the Hayabusa2 mission in virtual reality. We began with a talk using slides and then went on to examine the spacecraft. (OmniScope)

The current global pandemic has forced everyone to seek online alternatives for their classes, business meetings and social interactions. But even before this year, the need for alternatives to in-person gatherings was increasing. International conferences are expensive on both the wallet and environment, and susceptible to political friction, all of which undermine the goal of sharing ideas within a field. Meanwhile, experiences such as planetariums and museums are limited in reach to people within comfortable traveling distance.

Standard solutions have included web broadcasts of talks, or interactive meetings via platforms such as Zoom or Google hangouts. But these fail to capture the atmosphere of post-talk discussions that are as productive in a conference as the talks themselves. Similarly, you cannot talk to people individually without arranging a separate meeting.

Virtual reality offers an alternative that is closer to the experience of in-person gatherings, and where disadvantages are off-set with opportunities impossible in a regular meeting.

Imagine teaching a class on the solar system, where you could move your classroom from the baked surface of Mercury, to the sulphuric clouds of Venus and onto the icy moons of Jupiter.… Read more

Mapping the Surfaces of Our Solar System

 

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

Have We Photographed Our Nearest Planetary System?

Artist impression of Proxima Centauri c. Press “HD” on the player for the best image quality (E. Tasker).

The discovery of Proxima Centauri b in 2016 caused a flood excitement. We had found an extrasolar planet around our nearest star, making this the closest possible world outside of our solar system!

But despite its proximity, discovering more about this planet is difficult. Proxima Centauri b was found via the radial velocity technique, which measures the star’s wobble due to the gravity of the orbiting planet. This technique gives a minimum mass, the average distance between the star and planet and the time for one orbit, but no details about conditions on the planet surface.

If the planet had transited its star, we might have tried detecting starlight that passed through the planet’s atmosphere. This technique is known as transit spectroscopy, and reveals the composition of a planet’s atmosphere by detecting what wavelengths of light are absorbed by the molecules in the planet’s air. But searches for a transit proved fruitless, suggesting the planet’s orbit did not pass in front of the star from our viewpoint.

The radial velocity technique measures the motion of the star due to the gravity of the planet. As the star moves away from the Earth, its light becomes stretched and redder. As it moves back towards Earth, the light shifts to bluer wavelengths. The technique gives the planet’s period, distance from the star and its minimum mass. (E. Tasker)

Another option for planet characterization is to capture a direct image of the planet. This is one of the most exciting observational techniques, as it reveals the planet itself, not its influence on the star. Temporal changes in the planet’s light could reveal surface features as the planet rotates, and if enough light is detected to analyze different wavelengths, then the atmospheric composition could be deduced.

But direct imaging requires that the planet’s light can be differentiated from the much brighter star. With our current instruments, Proxima Centauri b orbits too close to its star to be distinguished. This seemed to close the door on finding out more about our nearest neighbors, until the discovery of a second planet in the system was announced early this year.

Also identified via the radial velocity technique, Proxima Centauri c has a minimum mass of 5.8 Earth masses. It sits further out than its sibling, with a chilly orbit that takes 5.2… Read more

Viruses, the Virosphere and Astrovirology

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

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?

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

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