Tag: NASA (page 2 of 5)

More Weird and Wild Planets

A world called TOI-849b could be the exposed, naked core of a former gas giant planet whose atmosphere was blasted away by its star.  Every day is a bad day on planet TOI-849b. . It hugs its star so tightly that a year – one trip around the star – takes less than a day. And it pays a high price for this close embrace: an estimated surface temperature of nearly 2,800 degrees Fahrenheit (1,500 degrees Celsius) It’s a scorcher even compared to Venus, which is 880 degrees Fahrenheit (471 degrees Celsius). About half the mass of our own Saturn, this planet orbits a Sun-like star more than 700 light-years from Earth. (NASA/Exoplanet Exploration Program)

The more we learn about the billions upon billions of planets that orbit beyond our solar system, the more we are surprised by the wild menagerie of objects out there.  From the start, many of these untolled planets have been startling, paradigm-breaking,  mysterious, hellish, potentially habitable and just plain weird.  Despite the confirmed detection of more than 4,000 exoplanets, the job of finding and characterizing these worlds remains in its early phases.  You could make the argument that  learning a lot more about these distant exoplanets and their solar systems is not just one of the great tasks of future astronomy, but of future science.

And that is why Many Worlds is returning to the subject of “Weird Planets,” which first appeared in this column at the opening of 2019.  It has been the most viewed column in our archive, and a day seldom goes by without someone — or some many people — decide to read it.

So here is not a really a sequel, but rather a continuation of writing about this unendingly rich subject.  And as I will describe further on,  almost all of the planets on display so far have been detected and characterized without ever having been seen.  The characteristics and colors presented in these (mostly) artistic renderings are the result of indirect observing and discovery — measuring how much light dims when a faraway planet crosses its host star, or how much the planet’s gravity causes its sun to move.

As a result, these planets are sometimes called “small, black shadows.” Scientists can infer a lot from the indirect measurements they make and from the beginnings of the grand effort to spectroscopically read the chemical makeup of exoplanet atmospheres. … Read more

How Radioactive Elements May Make Planets Suitable or Hostile to Life

An artist’s conception of a super Venus planet on the left and a super Earth on the right.  The question of what makes one planet habitable and one uninhabitable is a focus of many astrobiology researchers.  A new hypothesis looks at the presence of radioactive elements as an important factor in making a solar system habitable. (NASA/JPL-Caltech/Ames)

When describing exoplanets that are potentially promising candidates for life, scientists often use the terminology of the “habitable zone.”  This is a description of planets in orbit where temperatures, as predicted by the distance from the host star,  are not too cold for liquid water to exist on a planetary surface and also not to hot for all the water to burn off.

This planetary sweet spot, which not surprisingly Earth inhabits, is also more casually called the “Goldilocks zone” for exoplanets.

While there is certainly value to the habitable zone concept, there has also been scientific pushback to using the potential presence of liquid water as a primary or singular factor in predicting potential habitability.

There are just too many other factors that can play into habitability, some argue, and a focus on a planet’s distance from its host sun (and thus its temperature regime) is too narrow.  After all, several of the objects that just might support life in our own solar system are icy moons quite far from any solar system habitable zone.

With these concerns in the background, an interdisciplinary team of astrophysicists and planetary scientists at the University of California, Santa Cruz has begun to look at a source of heat in addition to suns and tidal forces that might play a role in making a planet habitable.

This source is the heat generated by the decay of long-lived radioactive elements such as uranium, thorium and potassium, which are found in stars and presumably on and in planets throughout the galaxies in greater or lesser amounts.

Using theory and modeling, they have concluded that the abundance of these radioactive elements in a planetary mantle can indeed give important insights into whether life might emerge there.

Supercomputer models of Earth’s magnetic field,  which is kept going thanks in part to the heat and subsequent convection produced by radioactive decay. (NASA)

Uranium is among the most widespread  elements on Earth — 500 times more common than gold It is present on the surface and in the mantle below. (Atomic Heritage Foundation.)

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Captured on Oct. 20 during the OSIRIS-REx mission’s Touch-And-Go (TAG) sample collection, the NASA spacecraft approached and touches down on asteroid Bennu’s surface. The dramatic sampling event, a NASA first,  brought the spacecraft down to sample site Nightingale.  The team on Earth received confirmation of successful touchdown at 6:08 p.m. EDT. (NASA/Goddard/University of Arizona)

Over 200 million miles away,  NASA’s OSIRIS-REx spacecraft on Tuesday unfurled its robotic arm and descended to the surface of the asteroid Bennu.  It appeared to crush some rock as it touched down, quickly fired some nitrogen gas to kick up the sample and then after 5 or 6 seconds it flew away to safety after a back-away burn.

One day after the “tag,” NASA officials announced that the sample collection appeared to have been it to be a successful,  and they released images and video of the dramatic scoop.  The spacecraft touched down within three feet of the Nightingale target location and NASA officials said that most of the sample collection occurred in the first three seconds.

The sample will consist of grains of a surface that has experienced none of the ever-active geology on Earth,  no modifications caused by life,  and little of the erosion and weathering.  In other words, it will be a sample of the very early solar system from which our planet arose.

The asteroid visit is the first ever accomplished by NASA, following in the path set by the Japan Aerospace Exploration Agency (JAXA) and its two Hayabusa missions.

“This amazing first for NASA demonstrates how an incredible team from across the country came together and persevered through incredible challenges to expand the boundaries of knowledge,” said NASA Administrator Jim Bridenstine. “Our industry, academic, and international partners have made it possible to hold a piece of the most ancient solar system in our hands.”

Artist rendering for OSIRIS-REX spacxecrsft as it approaches the asteroid Bennu to collect a sample and quickly depart. The “tag” took place on Oct. 20. (NASA)

While it remains somewhat unclear how much sample was collected by OSIRIS-REx, the mission’s principal investigator,  Dante Lauretta of the University of Arizona, said he was optimistic.

The sampling mechanism touched down in part on a rock about 8 inches wide, something that could have prevented the gathering mechanism from pressing up properly against the surface.

“I must have watched about a hundred times last night,” Lauretta, said during a news conference on Wednesday.

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Surprising Insights Into the Asteroid Bennu’s Past, as OSIRIS-REx Prepares For a Sample-Collecting “Tag”

Artist rendering of the OSIRIS-REx spacecraft as it will approach the asteroid Bennu to collect a sample of ancient, pristine solar system material. The  pick-up”tag” is scheduled for Oct. 20. (NASA Goddard Space Flight Center, University of Arizona)

Long before there was an Earth, asteroids large and small were orbiting our young sun.  Among them was one far enough out from the sun to contain water ice, as well as organic compounds with lots of carbon.  In its five billion years or so as an object,  the asteroid was hit and broken apart by other larger asteroids, probably grew some more as smaller asteroids hit it,  and then was smashed to bits again many millions of years ago.  Some of it might have even landed on Earth.

The product of this tumultuous early history is the asteroid now called Bennu, and the destination for NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) mission.  On October 20, the spacecraft will make its dramatic final descent, will touch the ground long enough to collect some samples of the surface, and then will in the months ahead return home with its prized catch.

The sample will consist of grains of a surface that have experienced none of the ever-active geology on Earth,  no modifications caused by life,  and little of the erosion and weathering.  In other words, it will be a sample of the very early solar system from which our planet arose.

“This will be our first chance to look at an ancient, carbon-rich environment – the most pristine example of the chemistry of the very early solar system,” said Daniel Glavin, an astrobiologist at NASA’s Space Flight Center and a co-investigator of the OSIRIS-REx team.  “Anything as ancient on early Earth would have been modified many times over.”

“But at Bennu we’ll see the solar system, and the Earth,  as it was chemically before all those changes took place.  This will be the kind of pristine pre-biotic chemistry that life emerged from.”

This image of Bennu was taken by the OSIRIS-REx spacecraft from a distance of around 50 miles (80 km).
(NASA/Goddard/University of Arizona)

Bennu is an unusual asteroid.  It orbits relatively close to Earth — rather than in the main asteroid belt between Mars and Jupiter — and that’s one of several main reasons why it was selected for a visit.  It is also an asteroid with significant amounts of primeval carbon and organics, which is gold for scientists eager to understand the early solar system, planet formation and the origin of life on Earth.… Read more

Why Not Assemble Space Telescopes In Space?

Artist rendering of an in-space assembled observatory concept with a 20-meter diameter primary mirror. (NASA’s  In Space Assembled Telescope Study, iSAT)

As we grow more ambitious in our desires to see further and more precisely in space, the need for larger and larger telescope mirrors becomes inevitable.  Only with collection of significantly more photons by a super large mirror can the the quality of the “seeing” significantly improve.

The largest mirror in space now is the Hubble Space Telescope at 2.4 meters (7.9 feet) and that will be overtaken by the long-delayed James Webb Space Telescope (JWST) at 6.5 meters (21.3 feet) when it launches (now scheduled for late 2021.)  But already astronomers and space scientists are pressing for larger mirrors to accomplish what the space telescopes of today cannot do.

This is evident in the National Academies of Sciences Decadal Survey underway which features four candidate Flagship-class observatories for the 2030s.    Three proposals call for telescope mirrors that are significantly larger than the Hubble’s, and the most ambitious by far is LUVOIR  which has been proposed at 15.1 meters (or 50 feet) or at 8 meters (about 30 feet), or maybe something in between.  A primary goal of LUVOIR, and the reason for the large size of its mirrors, is that it will be looking for signs of biology on distant exoplanets — an extremely ambitious and challenging goal.

The LUVOIR team would have argued for an even larger telescope mirror except that 15.1 meters is the maximum folded size that would fit into the storage space available on the super heavy lift rockets expected to be ready by the 2030s.

This desire for larger and larger space telescopes has rekindled dormant but long-present interest in having an alternative to sending multi-billion dollar payloads into space via one launch only.  The alternative is “in-space assembly,” and NASA has shown increased interest in pushing the idea and technology forward.

Nick Siegler, Chief Technologist of NASA’s Exoplanet Exploration Program at the Jet Propulsion Lab, and others proposed a study of robotic in-space assembly in 2018.  The idea was accepted by the NASA Director for Astrophysics Paul Hertz and Siegler said the results are promising.

The International Space Station’s robotic Canadarm2 and Dextre carry an instrument assembly after removing it from the trunk of the SpaceX Dragon cargo ship (upper right), which is docked at the Harmony node of the ISS. (NASA

“For space telescopes larger than LUVOIR, in-space assembly will probably be a necessity because it’s unlikely that heavy-lift rockets will be getting any bigger than what’s being built now,” Siegler said. … Read more

An “Elegant” New Theory on How Earth Became a Wet Planet

About 71 percent of the Earth’s surface is covered by water, and vast quantities of water are also locked up in minerals on and beneath the surface.  This image of Earth comes from NASA’s Earth Polychromatic Imaging Camera (EPIC) on NOAA’s Deep Space Climate Observatory (DSCOVR), orbits Earth from a distance of about 1 million miles away. (NASA)

One of the enduring puzzles of our planet is why it is so wet.

Since Earth formed relatively close to the sun,  planetary scientists have generally held that any of the water in the building blocks of early-forming Earth was baked out and so was unavailable to make oceans or our atmosphere.

That led to theories explaining the oceans and wet atmosphere of Earth as a later addition, brought to us by meteorites and comets formed beyond the solar system’s so-called “snow line,” where volatile compounds such as water can begin to condense into ice.

This snow line is a general area between Mars and Jupiter, and that means under this theory that our water would have had to come from awfully far away.   Further complicating this view is that the isotopic makeup of that distant water ice is somewhat different from much of the water on Earth.

Now, a new paper in the journal Science from Laurette Piani of  the Université de Lorraine and colleagues, argues that Earth’s water was simply acquired like most other of our materials, through accretion when the planet formed in the inner solar nebula.

To reach that conclusion, the group re-examined 13 meteorites of the parched type formed between Earth and the sun, and they found more than of enough hydrogen present to explain how Earth got so wet (wet for our solar system, that is.)

In fact, they extrapolated from their data that enough water was available in the nebular cloud  that accompanied the formation of our sun and formed those early meteorites — called enstatite chondrites — to create three times as much water as our oceans hold.

 

 

New measurements of enstatite chondrites indicate that water could have been primarily acquired from Earth’s building blocks. Additional water was delivered to Earth’s early oceans and atmosphere by water-rich material from comets and the outer asteroid belt. (Science)

“Our discovery shows that the Earth’s building blocks might have significantly contributed to the Earth’s water and that hydrogen bearing material was present in the inner solar system at the time of the Earth and rocky planet formation, even though the temperatures were too high for water to condense,'” Piani told me.… Read more

Cores, Planets and The Mission to Psyche

The asteroid Psyche will be the first metal-rich celestial body to be visited by a spacecraft.  The NASA mission launches in 2022 and is expected to arrive at the asteroid in late 2026.  A central question to be answered is whether Psyche is the exposed  core of a protoplanet that was stripped of its rocky mantle. (NASA)

Deep inside the rocky planets of our solar system, as well as some solar system moons,  is an iron-based core.

Some, such as Earth’s core,  have an inner solid phase and outer molten phase, but the solar system cores studied so far are of significantly varied sizes and contain a pretty wide variety of elements alongside the iron.  Mercury, for instance, is 85 percent core by volume and made up largely of iron, while our moon’s core is thought to be 20 percent of its volume and is mostly iron with some sulfur and nickel.

Iron cores like our own play a central role in creating a magnetic field around the planet, which in turn holds in the atmosphere and may well be essential to make a planet habitable.  They are also key to understanding how planets form after a star is forged and remaining dense gases and dust are kicked out to form a protoplanetary disk, where planets are assembled.

So cores are central to planetary science, and yet they are obviously hard to study.  The Earth’s core starts about 1,800 miles below the surface, and the cores of gas giants such as Jupiter are much further inward, and even their elemental makeups are not fully understood.

All this helps explains why the upcoming NASA mission to the asteroid Psyche is being eagerly anticipated, especially by scientists who focus on planetary formation.

Scheduled to launch in 2022, the spacecraft will travel to the main asteroid belt between Mars and Jupiter and home in on what has been described as an unusual “metal body,”  which is also one of the largest asteroids orbiting the sun.

While some uncertainty remains,  it appears that Psyche is the  exposed nickel-iron core of a long-ago emerging rocky protoplanet, with the rest of the planet stripped away by collisions billions of years ago.

An artist’s impression of solar system formation, and the formation of a protoplanetary disk filled with gases and dust that over time clump together and smash into each other to form larger and larger bodies. (Gemini Observatory/AURA artwork by Lynette Cook )

That makes Psyche a most interesting place to visit.… Read more

Our Sun, as Never Seen Before

This animation shows a series of views of the sun captured with the Extreme Ultraviolet Imager (EUI) on ESA/NASA’s Solar Orbiter on May 30, 2020. They show the sun’s appearance at a wavelength of 17 nanometers, which is in the extreme ultraviolet region of the electromagnetic spectrum. Images at this wavelength reveal the upper atmosphere of the sun and the corona, which has a temperature of more than a million degrees. Solar Orbiter/EUI Team (ESA & NASA; CSL, IAS, MPS, PMOD/WRC, ROB, UCL/MSSL)

The first images of the sun from the European Space Agency/NASA’s Solar Orbiter have been released and are stupendous.  They are the closest photos ever taken of the star that we orbit, and have already revealed some fascinating features that nobody knew existed.

Launched early this year, the spacecraft completed its first close pass of the sun in mid-June and began sending back images and data.

“These amazing images will help scientists piece together the sun’s atmospheric layers, which is important for understanding how it drives space weather near the Earth and throughout the solar system.” aid Holly Gilbert, NASA project scientist for the mission at NASA’s Goddard Space Flight Center.

The orbiter has already found previously unknown found across the sun miniature versions of the gigantic solar flares that reach out far into space.  But these much smaller versions,  deemed to be “campfires,” are so far seen by not understood.

Normally, the first images from a spacecraft confirm the instruments are working; scientists don’t expect new discoveries from them. But the Extreme Ultraviolet Imager, or EUI, on Solar Orbiter returned data hinting at solar features never observed in such detail.

“The campfires we are talking about here are the little nephews of solar flares, at least a million, perhaps a billion times smaller,” said mission principal investigator David Berghmans an astrophysicist at the Royal Observatory of Belgium said.

“When looking at the new high resolution EUI images, they are literally everywhere we look.”

Solar Orbiter spots ‘campfires’ on the Sun. Locations of campfires are annotated with white arrows.
Solar Orbiter/EUI Team (ESA & NASA; CSL, IAS, MPS, PMOD/WRC, ROB, UCL/MSSL)

That the Solar Orbiter has been able to continue on its mission has been no simple feat.

The coronavirus forced mission control at the European Space Operations Center (ESOC) in Darmstadt, Germany to close down completely for more than a week. During commissioning, the period when each instrument is extensively tested, ESOC staff were reduced to a skeleton crew.… 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

Exploring Our Sun Will Help Us Understand Habitability

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.

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