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Space News Update — June 12, 2020 —

Contents

In the News

Story 1:

Saturn's Moon Titan Drifting Away Faster Than Previously Thought

Story 2:

NASA's OSIRIS-REx Discovers Sunlight Can Crack Rocks on Asteroid Bennu

Story 3:

The Extraordinary Sample-Gathering System of NASA's Perseverance Mars Rover

Departments

The Night Sky

ISS Sighting Opportunities

NASA-TV Highlights

Space Calendar

Food for Thought

Space Image of the Week

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1. Saturn's Moon Titan Drifting Away Faster Than Previously Thought

Larger than the planet Mercury, Huge moon Titan is seen here as it orbits Saturn. Below Titan are the shadows cast by

Saturn's rings. This natural color view was created by combining six images captured by NASA's Cassini spacecraft on May

6, 2012. Credits: NASA/JPL-Caltech/Space Science Institute

Just as our own Moon floats away from Earth a tiny bit more each year, other moons are doing the same with their

host planets. As a moon orbits, its gravity pulls on the planet, causing a temporary bulge in the planet as it passes.

Over time, the energy created by the bulging and subsiding transfers from the planet to the moon, nudging it

farther and farther out. Our Moon drifts 1.5 inches (3.8 centimeters) from Earth each year.

Scientists thought they knew the rate at which the giant moon Titan is moving away from Saturn, but they recently

made a surprising discovery: Using data from NASA's Cassini spacecraft, they found Titan drifting a hundred times

faster than previously understood — about 4 inches (11 centimeters) per year.

The findings may help address an age-old question. While scientists know that Saturn formed 4.6 billion years

ago in the early days of the solar system, there's more uncertainty about when the planet's rings and its system of

more than 80 moons formed. Titan is currently 759,000 miles (1.2 million kilometers) from Saturn. The revised rate

of its drift suggests that the moon started out much closer to Saturn, which would mean the whole system

expanded more quickly than previously believed.

"This result brings an important new piece of the puzzle for the highly debated question of the age of the Saturn

system and how its moons formed," said Valery Lainey, lead author of the work published June 8 in Nature

Astronomy. He conducted the research as a scientist at NASA's Jet Propulsion Laboratory in Southern California

before joining the Paris Observatory at PSL University.

Making Sense of Moon Migration

The findings on Titan's rate of drift also provide important confirmation of a new theory that explains and predicts

how planets affect their moons' orbits.

For the last 50 years, scientists have applied the same formulas to estimate how fast a moon drifts from its planet,

a rate that can also be used to determine a moon's age. Those formulas and the classical theories on which they're

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based were applied to moons large and small all over the solar system. The theories assumed that in systems such

as Saturn's, with dozens of moons, the outer moons like Titan migrated outward more slowly than moons closer in

because they are farther from their host planet's gravity.

Four years ago, theoretical astrophysicist Jim Fuller, now of Caltech, published research that upended those

theories. Fuller's theory predicted that outer moons can migrate outward at a similar rate to inner moons because

they become locked in a different kind of orbit pattern that links to the particular wobble of a planet and slings

them outward.

"The new measurements imply that these kind of planet-moon interactions can be more prominent than prior

expectations and that they can apply to many systems, such as other planetary moon systems, exoplanets — those

outside our solar system — and even binary star systems, where stars orbit each other," said Fuller, a coauthor of

the new paper.

To reach their results, the authors mapped stars in the background of Cassini images and tracked Titan's position.

To confirm their findings, they compared them with an independent dataset: radio science data collected by Cassini.

During ten close flybys between 2006 and 2016, the spacecraft sent radio waves to Earth. Scientists studied how

the signal's frequency was changed by their interactions with their surroundings to estimate how Titan's orbit

evolved.

"By using two completely different datasets, we obtained results that are in full agreement, and also in agreement

with Jim Fuller's theory, which predicted a much faster migration of Titan," said coauthor Paolo Tortora, of Italy's

University of Bologna. Tortora is a member of the Cassini Radio Science team and worked on the research with the

support of the Italian Space Agency.

Managed by JPL, Cassini was an orbiter that observed Saturn for more than 13 years before exhausting its fuel

supply. The mission plunged it into the planet's atmosphere in September 2017, in part to protect its moon

Enceladus, which Cassini discovered might hold conditions suitable for life.

Source: NASA Return to Contents

This illustration imagines the view from NASA's Cassini spacecraft during one of its

final dives between Saturn and its innermost rings, as part of the mission's Grand Finale.

Cassini made 22 orbits that swooped between the rings and the planet before ending its

mission on Sept. 15, 2017, with a final plunge into Saturn.

Image Credit: NASA/JPL-Caltech

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2. NASA's OSIRIS-REx Discovers Sunlight Can Crack Rocks on Asteroid

Bennu

Examples of disaggregation (top) and linear fractures (bottom) in boulders on asteroid Bennu from images taken by

NASA’s OSIRIS-REX spacecraft. In the bottom row, fracture orientations are (d) west-northwest to east-southeast and (e,

f) north to south. Credits: NASA/Goddard/University of Arizona

Asteroids don’t just sit there doing nothing as they orbit the Sun. They get bombarded by meteoroids, blasted by

space radiation, and now, for the first time, scientists are seeing evidence that even a little sunshine can wear them

down.

Rocks on asteroid Bennu appear to be cracking as sunlight heats them up during the day and they cool down at

night, according to images from NASA’s OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security

- Regolith Explorer) spacecraft.

“This is the first time evidence for this process, called thermal fracturing, has been definitively observed on an

object without an atmosphere,” said Jamie Molaro of the Planetary Science Institute, Tucson, Arizona, lead author

of a paper appearing in Nature Communications June 9. “It is one piece of a puzzle that tells us what the surface

used to be like, and what it will be like millions of years from now.”

“Like any weathering process, thermal fracturing causes the evolution of boulders and planetary surfaces over time

- from changing the shape and size of individual boulders, to producing pebbles or fine-grained regolith, to breaking

down crater walls,” said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona, Tucson.

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“How quickly this occurs relative to other weathering processes tells us how and how quickly the surface has

changed.”

Rocks expand when sunlight heats them during the day and contract as they cool down at night, causing stress that

forms cracks that grow slowly over time. Scientists have thought for a while that thermal fracturing could be an

important weathering process on airless objects like asteroids because many experience extreme temperature

differences between day and night, compounding the stress. For example, daytime highs on Bennu can reach

almost 127 degrees Celsius or about 260 degrees Fahrenheit, and nighttime lows plummet to about minus 73

degrees Celsius or nearly minus 100 degrees Fahrenheit. However, many of the telltale features of thermal

fracturing are small, and before OSIRIS-REx got close to Bennu, the high-resolution imagery required to confirm

thermal fracturing on asteroids didn’t exist.

The mission team found features consistent with thermal fracturing using the spacecraft’s OSIRIS-REx Camera Suite

(OCAMS), which can see features on Bennu smaller than one centimeter (almost 0.4 inches). It found evidence of

exfoliation, where thermal fracturing likely caused small, thin layers (1 – 10 centimeters) to flake off of boulder

surfaces. The spacecraft also produced images of cracks running through boulders in a north-south direction, along

the line of stress that would be produced by thermal fracturing on Bennu.

Exfoliation features on a cliff face (a) and on boulders (b-f) with varying size and location on asteroid Bennu from images

taken by NASA’s OSIRIS-REX spacecraft. The bright dome on the horizon of panel (a) is a boulder behind the exfoliating

cliff. Credits: NASA/Goddard/University of Arizona

Other weathering processes can produce similar features, but the team’s analysis ruled them out. For example, rain

and chemical activity can produce exfoliation, but Bennu has no atmosphere to produce rain. Rocks squeezed by

tectonic activity can also exfoliate, but Bennu is too small for such activity. Meteoroid impacts do occur on Bennu

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and can certainly crack rocks, but they would not cause the even erosion of layers from boulder surfaces that were

seen. Also, there’s no sign of impact craters where the exfoliation is occurring.

Additional studies of Bennu could help determine how rapidly thermal fracturing is wearing down the asteroid, and

how it compares to other weathering processes. “We don’t have good constraints yet on breakdown rates from

thermal fracturing, but we can get them now that we can actually observe it for the first time in situ,” said OSIRIS-

REx project scientist Jason Dworkin of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Laboratory

measurements on the properties of the samples returned by the spacecraft in 2023 will help us learn more about

how this process works.”

Another area of research is how thermal fracturing affects our ability to estimate the age of surfaces. In general,

the more weathered a surface is, the older it is. For example, a region with a lot of craters is likely to be older than

an area with few craters, assuming impacts happen at a relatively constant rate across an object. However,

additional weathering from thermal fracturing could complicate an age estimate, because thermal fracturing is going

to happen at a different rate on different bodies, depending on things like their distance from the Sun, the length of

their day, and the composition, structure and strength of their rocks. On bodies where thermal fracturing is

efficient, then it may cause crater walls to break down and erode faster. This would make the surface look older

according the cratering record, when in fact it is actually younger. Or the opposite could occur. More research on

thermal fracturing on different bodies is needed to start to get a handle on this, according to Molaro.

The research was funded by NASA’s OSIRIS-REx Participating Scientist program as well as the OSIRIS-REx mission.

NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems

engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona,

Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s

science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft

and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-

REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s

Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

NASA is exploring our Solar System and beyond, uncovering worlds, stars, and cosmic mysteries near and far with

our powerful fleet of space and ground-based missions.

Source: NASA Return to Contents

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3. The Extraordinary Sample-Gathering System of NASA's Perseverance

Mars Rover

Engineers and technicians working on the Mars 2020 Perseverance team insert 39 sample tubes into the belly of the

rover. Each tube is sheathed in a gold-colored cylindrical enclosure to protect it from contamination. Perseverance rover

will carry 43 sample tubes to Mars' Jezero Crater. The image was taken at NASA's Kennedy Space Center in Florida on

May 20, 2020. Image Credit: NASA/JPL-Caltech

The samples Apollo 11 brought back to Earth from the Moon were humanity's first from another celestial body.

NASA's upcoming Mars 2020 Perseverance rover mission will collect the first samples from another planet (the

red one) for return to Earth by subsequent missions. In place of astronauts, the Perseverance rover will rely on

the most complex, capable and cleanest mechanism ever to be sent into space, the Sample Caching System.

The final 39 of the 43 sample tubes at the heart of the sample system were loaded, along with the storage

assembly that will hold them, aboard NASA's Perseverance rover on May 20 at Kennedy Space Center in

Florida. (The other four tubes had already been loaded into different locations in the Sample Caching System.)

The integration of the final tubes marks another key step in preparation for the opening of the rover's launch

period on July 17.

"While you cannot help but marvel at what was achieved back in the days of Apollo, they did have one thing

going for them we don't: boots on the ground," said Adam Steltzner, chief engineer for the Mars 2020

Perseverance rover mission at NASA's Jet Propulsion Laboratory in Southern California. "For us to collect the

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first samples of Mars for return to Earth, in place of two astronauts we have three robots that have to work

with the precision of a Swiss watch."

While many people think of the Perseverance rover as one robot, it's actually akin to a collection of robots

working together. Located on the front of the Perseverance rover, the Sample Caching System itself is

composed of three robots, the most visible being the rover's 7-foot-long (2-meter-long) robotic arm. Bolted to

the front of the rover's chassis, the five-jointed arm carries a large turret that includes a rotary percussive drill

to collect core samples of Mars rock and regolith (broken rock and dust).

The second robot looks like a small flying saucer built into the front of the rover. Called the bit carousel, this

appliance is the ultimate middleman for all Mars sample transactions: It will provide drill bits and empty

sample tubes to the drill and will later move the sample-filled tubes into the rover chassis for assessment and

processing.

The third robot in the Sample Caching System is the 1.6-foot-long (0.5 meter-long) sample handling arm

(known by the team as the "T. rex arm"). Located in the belly of the rover, it picks up where the bit carousel

leaves off, moving sample tubes between storage and documentation stations as well as the bit carousel.

Clocklike Precision

All of these robots need to run with clocklike precision. But where the typical Swiss chronometer has fewer

than 400 parts, the Sample Caching System has more than 3,000.

"It sounds like a lot, but you begin to realize the need for complexity when you consider the Sample Caching

System is tasked with autonomously drilling into Mars rock, pulling out intact core samples and then sealing

them hermetically in hyper-sterile vessels that are essentially free of any Earth-originating organic material

that could get in the way of future analysis," said Steltzner. "In terms of technology, it is the most

complicated, most sophisticated mechanism that we have ever built, tested and readied for spaceflight."

The mission's goal is to collect a dozen or more samples. So how does this three-robot, steamer-trunk-sized

labyrinthine collection of motors, planetary gearboxes, encoders and other devices all meticulously work

together to take them?

"Essentially, after our rotary percussive drill takes a core sample, it will turn around and dock with one of the

four docking cones of the bit carousel," said Steltzner. "Then the bit carousel rotates that Mars-filled drill bit

and a sample tube down inside the rover to a location where our sample handling arm can grab it. That arm

pulls the filled sample tube out of the drill bit and takes it to be imaged by a camera inside the Sample

Caching System."

After the sample tube is imaged, the small robotic arm moves it to the volume assessment station, where a

ramrod pushes down into the sample to gauge its size. "Then we go back and take another image," said

Steltzner. "After that, we pick up a seal - a little plug - for the top of the sample tube and go back to take yet

another image."

Next, the Sample Caching System places the tube in the sealing station, where a mechanism hermetically seals

the tube with the cap. "Then we take the tube out," added Steltzner, "and we return it to storage from where

it first began."

Getting the system designed and manufactured, then integrated into Perseverance has been a seven-year

endeavor. And the work isn't done. As with everything else on the rover, there are two versions of the Sample

Caching System: an engineering test model that will stay here on Earth and the flight model that will travel to

Mars.

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"The engineering model is identical in every way possible to the flight model, and it's our job to try to break

it," said Kelly Palm, the Sample Caching System integration engineer and Mars 2020 test lead at JPL. "We do

that because we would rather see things wear out or break on Earth than on Mars. So we put the engineering

test model through its paces to inform our use of its flight twin on Mars."

To that end, the team uses different rocks to simulate types of terrain. They drill them from various angles to

anticipate any imaginable situation the rover could be in where the science team might want to gather a

sample.

"Every once in a while, I have to take a minute and contemplate what we are doing," said Palm. "Just a few

years ago I was in college. Now I am working on the system that will be responsible for collecting the first

samples from another planet for return to Earth. That is pretty awesome."

About the Mission

Perseverance is a robotic scientist weighing about 2,260 pounds (1,025 kilograms). The rover's astrobiology

mission will search for signs of past microbial life. It will characterize the planet's climate and geology, collect

samples for future return to Earth, and pave the way for human exploration of the Red Planet. No matter what

day Perseverance lifts off during its July 17-Aug. 11 launch period, it will land at Mars' Jezero Crater on Feb.

18, 2021.

The two subsequent (follow-on) missions required to return the mission's collected samples to Earth are

currently being planned by NASA and the European Space Agency.

JPL engineers monitor testing of the Perseverance rover's Sample Caching System. Image credit: NASA/JPL-Caltech

Source: NASA Return to Content

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The Night Sky

FRIDAY, JUNE 5

SUNDAY, JUNE 14

After dark look southeast for orange Antares, "the Betelgeuse of summer." Both are 1st-magnitude "red"

supergiants. Around and upper right of Antares are the other, whiter stars of upper Scorpius forming their

distinctive shape. The rest of the Scorpion curls down toward the horizon.

Also right after dark, spot Arcturus way up high toward the south. Three fists below it is Spica. A fist and a half

to Spica's lower right, four-star Corvus, the springtime Crow, is heading down and away as spring draws to a

close.

MONDAY, JUNE 15

It's only five days to summer, but as twilight fades, look for wintry Capella very low in the north-northwest very

out of season. The farther south you are, the lower Capella will appear; you may need binoculars. But if you're

as far north as Montreal or a Portland (either Oregon or Maine), Capella is actually circumpolar.

TUESDAY, JUNE 16

After dark, Vega dominates the eastern sky. Barely lower left of it is 4th-magnitude Epsilon Lyrae, the famous

Double-Double. Epsilon forms one corner of a roughly equilateral triangle with Vega and Zeta Lyrae. The

triangle is less than 2° on a side, hardly the width of your thumb at arm's length.

Source: Sky and Telescope Return to Contents

FRIDAY, JUNE 12

Mercury remains under Pollux and Castor in twilight, as

shown below, but it has faded to magnitude 1.3. That's less

than half as bright as Procyon, mag 0.4, which twinkles

about two fists at arm's length to its left. Catch Mercury

this evening while you still can; it's fading fast and sinking

low.

Last-quarter Moon tonight (exactly last-quarter at 2:24

a.m. Saturday morning EDT). The Moon rises around 1 or 2

a.m. local daylight-saving time, with bright Mars,

magnitude –0.2, shining dramatically orange above or

upper right of it by about 4°. As Saturday's dawn brightens,

the Moon-Mars pair stands high in the southeast.

Neptune, only 8th magnitude, lurks in their far dark

background.

SATURDAY, JUNE 13

As we count down the last seven days to official summer

(the solstice is on June 20th), the big Summer Triangle

shines high and proud in the east after dusk. Its top star is

bright Vega. Deneb is the brightest star to Vega's lower

left, by 2 or 3 fists at arm's length. Look for Altair farther to

Vega's lower right. Of the three, Altair is midway in

brightness between Vega and Deneb.

If you have a dark enough sky, the Milky Way runs across

the Triangle's lower part.

Mercury remains under Pollux and Castor in twilight, though at magnitude 1.3 it no longer outshines even Pollux, magnitude 1.2. In fact Mercury will

appear even fainter considering the greater atmospheric extinction at its lower altitude and the

brighter sky there too. Binoculars may help.

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ISS Sighting Opportunities (from Denver)

No sightings at Denver through Tuesday Jun 16, 2020

Sighting information for other cities can be found at NASA’s Satellite Sighting Information

NASA-TV Highlights (all times Eastern Time Zone)

NASA TV Schedule for Week of June 8

Live Programming

June 12, Friday

11 a.m. - SpaceCast Weekly (All Channels)

June 16, Tuesday

11:30 a.m. – International Space Station Expedition 63 in-flight interviews with CBS News, CNN and Fox

Business News and NASA astronauts Bob Behnken and Doug Hurley (All Channels)

Watch NASA TV online by going to the NASA website. Return to Contents

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Space Calendar

Jun 12 - Mars Passes 1.7 Degrees From Neptune

Jun 12 - Webinar: Emerging Space Program - Lessons Learned for the Future

Jun 13 - Starlink 8 (60)/ SkySat 16-18 Falcon 9 Launch

Jun 13 - Amor Asteroid 2020 KB3 Near-Earth Flyby (0.008 AU)

Jun 13 - Amor Asteroid 2020 LC Near-Earth Flyby (0.032 AU)

Jun 13 - Apollo Asteroid 2020 JU1 Near-Earth Flyby (0.049 AU)

Jun 13 - Atira Asteroid 2010 XB11 Closest Approach To Earth (0.706 AU)

Jun 13 - 10th Anniversary (2010), Hayabusa (MUSES-C) Return To Earth

Jun 13-19 - Summer School: Matrix Membranes and Emergent Spacetime, Dublin, Ireland

Jun 14 - RISAT-2BR2/ KSM PSLV Launch

Jun 14 - Apollo Asteroid 2017 MF7 Near-Earth Flyby (0.009 AU)

Jun 14 - 35th Anniversary (1985), Vega 2, USSR Venus Landing/Balloon

Jun 14 - 45th Anniversary (1975), Venera 10, Venus Landing

Jun 15 - Teleconference: Astronomy and Astrophysics Advisory Committee (AAAC)

Jun 15 - Online: Space Nuclear Propulsion Technologies Meeting 3 - DOE Perspectives on NEP/NTP

Jun 15-16 - Webinar: 49th World Congress on Microbiology

Jun 15-19 - Zoom Conference: Astrochemical Frontiers - Quarantine Edition

Jun 15-19 - 2020 AIAA Aviation and Aeronautics Virtual Forum and Exposition

Jun 15-19 - GEO Virtual Symposium 2020

Jun 15-19 - International Astrophysics and Space Conference 2020, Tbilisi, Georgia

Jun 15-19 - Teleparallel Gravity Online Workshop 2020

Jun 15-19 - Online Workshop: Computations That Matter 2020

Jun 15-19 - Cloudy Workshop 2020, Athens, Greece

Jun 16 - Beidou 3 CZ-3B Launch

Jun 16 - Apollo Asteroid 2020 KP6 Near-Earth Flyby (0.009 AU)

Jun 16 - Aten Asteroid 2014 OL339 Closest Approach To Earth (0.299 AU)

Jun 16 - eRum2020 Satellite Online Event: Hackathon on Spatial Networks

Jun 16-17 - Online: Space Weather Operations and Research Infrastructure Workshop Part 1

Source: JPL Space Calendar Return to Contents

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Food for Thought

Virginia Tech Research Provides New Explanation for Neutrino

Anomalies in Antarctica

Scientists remain perplexed by the activity, with some 40 papers so far giving

wildly different answers

A map (left) and zoom-in (right) of Antarctica, displaying the two anomalous upward-pointing events — represented by

red dots — observed by the ANITA experiment, overlaid with surface ice speed (represented by purple/blue coloring) and

500-meter surface elevation contours. The top red dot represents the anomaly recorded in 2018, while the lower dot

represents the anomaly recorded in 2016. Both events lie in low surface ice-speed and high-elevation of 1.86 to 2.17 mile

regions, according to Shoemaker. Image courtesy Ian Shoemaker.

A new research paper co-authored by a Virginia Tech assistant professor of physics provides a new

explanation for two recent strange events that occurred in Antarctica – high-energy neutrinos appearing to

come up out of the Earth on their own accord and head skyward.

The anomalies occurred in 2016 and 2018 and were discovered by scientists searching for ultra-high-energy

cosmic rays and neutrinos coming from space, all tracked by an array of radio antennas attached to a balloon

floating roughly 23 miles above the South Pole. Neutrinos are exceedingly small particles, created in a number

of ways, including exploding stars and gamma ray bursts. They are everywhere within the universe and are

tiny enough to pass through just about any object, from people to lead to buildings and the Earth itself.

The events were discovered by scientists at the ANITA experiment — that’s short for Antarctic Impulsive

Transient Antenna, started in 2006 — in the South Pole. Twice, ANITA scientists discovered radio signals

mimicking highly energetic neutrinos seemingly coming upward out of the ground on their own accord.

Scientists remain perplexed by the activity, with some 40 papers so far giving wildly different answers — the

pulses are neutrinos that passed unencumbered through the entire core of Earth and came out of the ground;

the pulses are the long sought-after “fourth” neutrino known as the sterile neutrino; the mysterious “dark

matter” of space is to blame; or this is an entirely unknown frontier of particle and/or astrophysics physics

begging for a Nobel.

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Ian Shoemaker, an assistant professor in the Department of Physics and the Center for Neutrino Physics, both

part of the Virginia Tech College of Science, has a different, simpler explanation. In a recent paper published

in the journal Annals of Glaciology, Shoemaker and several colleagues posit that the anomalies are not from

neutrinos, but are merely unflipped reflections of the ultra-high-energy cosmic rays that arrive from space —

miss the top layer ice — then enter the ground, striking deep, compacted snow known as firn.

“We think sub-surface firn is the culprit,” said Shoemaker, adding that “firn is something between snow and

glacial ice. It’s compacted snow that’s not quite dense enough to be ice. So, you can have density inversions,

with ranges where you go from high density back to low density, and those crucial sorts of interfaces where

this reflection can happen and could explain these events.”

Shoemaker was joined on the paper by his former Ph.D. advisor, Alexander Kusenko of the University of

California Los Angeles’ Department of Physics and Astronomy; Andrew Romero-Wolf, a member of the ANITA

team and a researcher at the California Institute of Technology’s Jet Propulsion Laboratory; and four other

researchers, including two glaciologists: Dustin Shroeder from Stanford University and Martin Siegert from

Imperial College London.

Call it a case of Occam’s razor (that’s the centuries-old theory that the simplest solution in most likely the

correct one, for those who skipped philosophy in college), but Shoemaker isn’t railing ANITA. “Whatever

ANITA has found, it is very interesting, but it may not be a Nobel prize-winning particle physics discovery.” But

he’s not discounting that the so-called anomalies have no scientific merit. “ANITA still could have discovered

something interesting about glaciology instead of particle physics, it could be ANITA discovered some unusual

small glacial lakes.”

Sub-glacial lakes were another consideration by Shoemaker and his team for the reflections. These lakes, deep

underground, though, are too far spread apart according to current research, and hence are not the most

likely explanation. But if there are far more lakes than previously known, this discovery would be a big win for

scientists who study the landscape and interior of Antarctica. Shoemaker and his team suggest scientists

purposefully blast radio signals into the areas where the anomalies occurred.

“I didn’t know anything about them, but they really do exist,” Shoemaker said of sub-glacier lakes in

Antarctica. “There are lakes under the ice in Antarctica, and those would have the right reflective properties,

but they’re not widespread enough. Our idea is that part of the radio pulse from a cosmic ray can get deep

into the ice before reflecting, so you can have the reflection without the phase flip. Without flipping the wave,

in that case, it really looks like a neutrino.”

Shoemaker added that, “When cosmic rays, or neutrinos, go through ice at very high energies, they scatter on

materials inside the ice, on protons and electrons, and they can make a burst of radio, a big nice radio signal

that scientists can see. The problem is that these signals have the radio pulse characteristic of a neutrino, but

are appear to be traversing vastly more than is possible given known physics. Ordinary neutrinos just don’t so

this. But cosmic rays at these energies are common occurrences and have been seen by many, many

experiments.”

Source: EurekAlert/Virginia Tech Return to Contents

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Space Image of the Week

NGC 2359: Thor's Helmet Image Credit & Copyright: Martin Pugh

Explanation: NGC 2359 is a helmet-shaped cosmic cloud with wing-like appendages popularly called Thor's Helmet. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. In fact, the helmet is more like an interstellar bubble, blown as a fast wind from the bright, massive star near the bubble's center inflates a region within the surrounding molecular cloud. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away in the constellation of the Great Overdog. The remarkably sharp image is a mixed cocktail of data from broadband and narrowband filters using three

different telescopes. It captures natural looking stars and the details of the nebula's filamentary structures. The

predominant bluish hue is strong emission from doubly ionized oxygen atoms in the glowing gas.

Source: NASA APOD Return to Contents