Category Archives: Research

Improving the Hubble Constant

Very interesting work coming out of UCLA using Quasars to measure the expansion rate of the universe. The image above and the press release below are from a UCLA press release, the image is courtesy NASA Hubble Space Telescope, Tommaso Treu/UCLA, and Birrer et al

Quasars as it turns out are pretty useful, didn’t scientists use them to prove quantum entanglement? I believe they did.

UCLA: The question of how quickly the universe is expanding has been bugging astronomers for almost a century. Different studies keep coming up with different answers — which has some researchers wondering if they’ve overlooked a key mechanism in the machinery that drives the cosmos.
Now, by pioneering a new way to measure how quickly the cosmos is expanding, a team led by UCLA astronomers has taken a step toward resolving the debate. The group’s research is published today in Monthly Notices of the Royal Astronomical Society.

At the heart of the dispute is the Hubble constant, a number that relates distances to the redshifts of galaxies — the amount that light is stretched as it travels to Earth through the expanding universe. Estimates for the Hubble constant range from about 67 to 73 kilometers per second per megaparsec, meaning that two points in space 1 megaparsec apart (the equivalent of 3.26 million light-years) are racing away from each other at a speed between 67 and 73 kilometers per second.

“The Hubble constant anchors the physical scale of the universe,” said Simon Birrer, a UCLA postdoctoral scholar and lead author of the study. Without a precise value for the Hubble constant, astronomers can’t accurately determine the sizes of remote galaxies, the age of the universe or the expansion history of the cosmos.

Most methods for deriving the Hubble constant have two ingredients: a distance to some source of light and that light source’s redshift. Looking for a light source that had not been used in other scientists’ calculations, Birrer and colleagues turned to quasars, fountains of radiation that are powered by gargantuan black holes. And for their research, the scientists chose one specific subset of quasars — those whose light has been bent by the gravity of an intervening galaxy, which produces two side-by-side images of the quasar on the sky.

Light from the two images takes different routes to Earth. When the quasar’s brightness fluctuates, the two images flicker one after another, rather than at the same time. The delay in time between those two flickers, along with information about the meddling galaxy’s gravitational field, can be used to trace the light’s journey and deduce the distances from Earth to both the quasar and the foreground galaxy. Knowing the redshifts of the quasar and galaxy enabled the scientists to estimate how quickly the universe is expanding.

The UCLA team, as part of the international H0liCOW collaboration, had previously applied the technique to study quadruply imaged quasars, in which four images of a quasar appear around a foreground galaxy. But quadruple images are not nearly as common — double-image quasars are thought to be about five times as abundant as the quadruple ones.

To demonstrate the technique, the UCLA-led team studied a doubly imaged quasar known as SDSS J1206+4332; they relied on data from the Hubble Space Telescope, the Gemini and W.M. Keck observatories, and from the Cosmological Monitoring of Gravitational Lenses, or COSMOGRAIL, network — a program managed by Switzerland’s Ecole Polytechnique Federale de Lausanne that is aimed at determining the Hubble constant.
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A New Crater Discovery

Wow, this is very cool!

NASA/Steve Cole – An international team of researchers, including a NASA glaciologist, has discovered a large meteorite impact crater hiding beneath more than a half-mile of ice in northwest Greenland. The crater — the first of any size found under the Greenland ice sheet — is one of the 25 largest impact craters on Earth, measuring roughly 1,000 feet deep and more than 19 miles in diameter, an area slightly larger than that inside Washington’s Capital Beltway.

The group, led by researchers from the University of Copenhagen’s Centre for GeoGenetics at the Natural History Museum of Denmark worked for the past three years to verify their discovery, which they initially made in 2015 using NASA data. Their finding is published in the Nov. 14 issue of the journal Science Advances.

“NASA makes the data it collects freely available to scientists and the public all around the world,” said Joe MacGregor, a NASA glaciologist at Goddard Space Flight Center in Greenbelt, Maryland, who became involved in the investigation in its early stages. “That set the stage for our Danish colleagues’ ‘Eureka’ moment.”

The researchers first spotted the crater in July 2015, while they were inspecting a new map of the topography beneath Greenland’s ice sheet that used ice-penetrating radar data primarily from NASA’s Operation IceBridge — a multi-year airborne mission to track changes in polar ice — and earlier NASA airborne missions in Greenland. The scientists noticed an enormous, previously unexamined circular depression under Hiawatha Glacier, sitting at the very edge of the ice sheet in northwestern Greenland.
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Chandra’s Look at Kes 75

NASA: Scientists have confirmed the identity of the youngest known pulsar in the Milky Way galaxy using data from NASA’s Chandra X-ray Observatory. This result could provide astronomers new information about how some stars end their lives.

After some massive stars run out of nuclear fuel, then collapse and explode as supernovas, they leave behind dense stellar nuggets called “neutron stars”. Rapidly rotating and highly magnetized neutron stars produce a lighthouse-like beam of radiation that astronomers detect as pulses as the pulsar’s rotation sweeps the beam across the sky.

Since Jocelyn Bell Burnell, Anthony Hewish, and their colleagues first discovered pulsars through their radio emission in the 1960s, over 2,000 of these exotic objects have been identified. However, many mysteries about pulsars remain, including their diverse range of behaviors and the nature of stars that form them.

New data from Chandra are helping address some of those questions. A team of astronomers has confirmed that the supernova remnant Kes 75, located about 19,000 light years from Earth, contains the youngest known pulsar in the Milky Way galaxy.

The rapid rotation and strong magnetic field of the pulsar have generated a wind of energetic matter and antimatter particles that flow away from the pulsar at near the speed of light . This pulsar wind has created a large, magnetized bubble of high-energy particles called a pulsar wind nebula, seen as the blue region surrounding the pulsar.

In this composite image of Kes 75, high-energy X-rays observed by Chandra are colored blue and highlight the pulsar wind nebula surrounding the pulsar, while lower-energy X-rays appear purple and show the debris from the explosion. A Sloan Digital Sky Survey optical image reveals stars in the field.

The Chandra data taken in 2000, 2006, 2009, and 2016 show changes in the pulsar wind nebula with time. Between 2000 and 2016, the Chandra observations reveal that the outer edge of the pulsar wind nebula is expanding at a remarkable 1 million meters per second, or over 2 million miles per hour.

This high speed may be due to the pulsar wind nebula expanding into a relatively low-density environment. Specifically, astronomers suggest it is expanding into a gaseous bubble blown by radioactive nickel formed in the explosion and ejected as the star exploded. This nickel also powered the supernova light, as it decayed into diffuse iron gas that filled the bubble. If so, this gives astronomers insight into the very heart of the exploding star and the elements it created.

The expansion rate also tells astronomers that Kes 75 exploded about five centuries ago as seen from Earth. (The object is some 19,000 light years away, but astronomers refer to when its light would have arrived at Earth.) Unlike other supernova remnants from this era such as Tycho and Kepler, there is no known evidence from historical records that the explosion that created Kes 75 was observed.

Why wasn’t Kes 75 seen from Earth? The Chandra observations along with previous ones from other telescopes indicate that the interstellar dust and gas that fill our Galaxy are very dense in the direction of the doomed star. This would have rendered it too dim to be seen from Earth several centuries ago.

The brightness of the pulsar wind nebula has decreased by 10% from 2000 to 2016, mainly concentrated in the northern area, with a 30% decrease in a bright knot. The rapid changes observed in the Kes 75 pulsar wind nebula, as well as its unusual structure, point to the need for more sophisticated models of the evolution of pulsar wind nebulas.

A paper describing these results appeared in The Astrophysical Journal and is available online. The authors are Stephen Reynolds, Kazimierz Borokowski, and Peter Gwynne from North Carolina State University. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

Image credit: X-ray: NASA/CXC/NCSU/S. Reynolds; Optical: PanSTARRS

Europa Radiation Mapping

Looking to the future of exploration of the Jovian moon Europa, radiation mapping is key. The top picture is a fun thought experiment. Both images are from NASA of course. So how far below the surface does the radiation penetrate? Research suggests not all that far.

NASA (Gretchen McCartney, Dwayne Brown / JoAnna Wendel) New comprehensive mapping of the radiation pummeling Jupiter’s icy moon Europa reveals where scientists should look — and how deep they’ll have to go — when searching for signs of habitability and biosignatures.

Since NASA’s Galileo mission yielded strong evidence of a global ocean underneath Europa’s icy shell in the 1990s, scientists have considered that moon one of the most promising places in our solar system to look for ingredients to support life. There’s even evidence that the salty water sloshing around the moon’s interior makes its way to the surface.

By studying this material from the interior, scientists developing future missions hope to learn more about the possible habitability of Europa’s ocean. However, Europa’s surface is bombarded by a constant and intense blast of radiation from Jupiter. This radiation can destroy or alter material transported up to the surface, making it more difficult for scientists to know if it actually represents conditions in Europa’s ocean.

As scientists plan for upcoming exploration of Europa, they have grappled with many unknowns: Where is the radiation most intense? How deep do the energetic particles go? How does radiation affect what’s on the surface and beneath — including potential chemical signs, or biosignatures, that could imply the presence of life.

A new scientific study, published today in Nature Astronomy, represents the most complete modeling and mapping of radiation at Europa and offers key pieces to the puzzle. The lead author is Tom Nordheim, research scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California.

“If we want to understand what’s going on at the surface of Europa and how that links to the ocean underneath, we need to understand the radiation,” Nordheim said. “When we examine materials that have come up from the subsurface, what are we looking at? Does this tell us what is in the ocean, or is this what happened to the materials after they have been radiated?”

Using data from Galileo’s flybys of Europa two decades ago and electron measurements from NASA’s Voyager 1 spacecraft, Nordheim and his team looked closely at the electrons blasting the moon’s surface. They found that the radiation doses vary by location. The harshest radiation is concentrated in zones around the equator, and the radiation lessens closer to the poles.

Mapped out, the harsh radiation zones appear as oval-shaped regions, connected at the narrow ends, that cover more than half of the moon.

“This is the first prediction of radiation levels at each point on Europa’s surface and is important information for future Europa missions,” said Chris Paranicas, a co-author from the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland.

Now scientists know where to find regions least altered by radiation, which could be crucial information for the JPL-led Europa Clipper, NASA’s mission to orbit Jupiter and monitor Europa with about 45 close flybys. The spacecraft may launch as early as 2022 and will carry cameras, spectrometers, plasma and radar instruments to investigate the composition of the moon’s surface, its ocean, and material that has been ejected from the surface.

In his new paper, Nordheim didn’t stop with a two-dimensional map. He went deeper, gauging how far below the surface the radiation penetrates, and building 3D models of the most intense radiation on Europa. The results tell us how deep scientists need to dig or drill, during a potential future Europa lander mission, to find any biosignatures that might be preserved.

The answer varies, from 4 to 8 inches (10 to 20 centimeters) in the highest-radiation zones – down to less than 0.4 inches (1 centimeter) deep in regions of Europa at middle- and high-latitudes, toward the moon’s poles.

To reach that conclusion, Nordheim tested the effect of radiation on amino acids, basic building blocks for proteins, to figure out how Europa’s radiation would affect potential biosignatures. Amino acids are among the simplest molecules that qualify as a potential biosignature, the paper notes.

“The radiation that bombards Europa’s surface leaves a fingerprint,” said Kevin Hand, co-author of the new research and project scientist for the potential Europa Lander mission. “If we know what that fingerprint looks like, we can better understand the nature of any organics and possible biosignatures that might be detected with future missions, be they spacecraft that fly by or land on Europa.

Europa Clipper’s mission team is examining possible orbit paths, and proposed routes pass over many regions of Europa that experience lower levels of radiation, Hand said. “That’s good news for looking at potentially fresh ocean material that has not been heavily modified by the fingerprint of radiation.”

JPL, a division of Caltech in Pasadena, California, manages the Europa Clipper mission for NASA’s Science Mission Directorate in Washington.

For more information about NASA’s Europa Clipper mission, visit:

Sample Return Technology

How does one go about the extraordinarily difficult task of returning a sample from another world back to Earth? Honey Bee Robotics is testing technology to do just that – the Planet Vac.

Credits: NASA Photo / Lauren Hughes

From NASA/Honey Bee Robotics/Masten Space Systems:

Just a sample will do.

Honeybee Robotics in Pasadena, California, flight tested its pneumatic sampler collection system, PlanetVac, on Masten Space Systems’ Xodiac rocket on May 24, launching from Mojave, California, and landing to collect a sample of more than 320 grams of top soil from the surface of the desert floor.

“The opportunity to test a technology on Earth before it is destined for another planet allows researchers and mission planners to have confidence that once the technology arrives to its space destination it will work,” said Ryan Dibley, NASA Flight Opportunities program campaign manager. Flight Opportunities program funded the test flight.

PlanetVac is a surface soil collection system for a sample return mission. The configuration tested would replace a foot pad of a planetary lander spacecraft. The goal is to bring back a sample of surface soil from a celestial body.

“Bringing something back from another planet, celestial body, is the Holy Grail of planetary science,” said Justin Spring, senior project engineer for Honeybee Robotics. “It allows you to have something from another world, here, so Earth instruments can analyze it. We’re still analyzing what we collected from the moon years ago!”

The pneumatic sampler foot pad starts operation after the lander touches down on a surface. Compressed gas is injected into the foot pad enclosure, lofting the soil into a cyclone separator for collection.

“What it does is kind of like your vacuum,” said Spring. “It creates an area of high pressure in the front and uses an area of low pressure in the back to suck up the sample. The best thing about PlanetVac is how simple it is. Aside from a single actuator to trigger the gas flow, the system is entirely pneumatic, which reduces complexity and risk.”

“There are other ways to collect samples,” he adds. “The Mars Curiosity rover uses a drill. The Mars Phoenix lander had a scoop. But to keep it simple when all you need is surface dirt then using this pneumatic system can bring the sample back.”

“The Flight Opportunities program allowed us to take the PlanetVac idea and actually strap it on to Masten’s rocket putting it in a situation more realistic to what it might encounter in a space mission,” said Spring. “This reduces the risk since we now know it can survive both landing and heating loads as well as the rocket environment and still collect the sample and retain it to come back.”

Through the Flight Opportunities program, the Space Technology Mission Directorate (STMD) selects promising technologies from industry, academia and government for testing on commercial launch vehicles and enables public-private partnerships for the agency. The program is funded by STMD and managed at NASA’s Armstrong Flight Research Center in Edwards, California.

STMD is responsible for developing the crosscutting, pioneering, new technologies and capabilities needed by the agency to achieve its current and future missions.

New Ganymede Data

From the Galileo mission over 20 years ago. The data comes from the first flyby of the moon. I worked with a group that would collect all sorts of data and it went to two places, one into a US federal aide report to get money to collect more data to put into the next years federal aide report (and so on) and the other place was a file cabinet. The data amounted to nothing at all. Now not ALL of the people wasted the data but some did. Terrible. So when I see data that gets multiple looks it makes me smile. Thankfully ESA and NASA are both taking fresh looks at old data.

And this is new Ganymede data so it is REALLY fun.

NASA: Far across the solar system, from where Earth appears merely as a pale blue dot, NASA’s Galileo spacecraft spent eight years orbiting Jupiter. During that time, the hearty spacecraft — slightly larger than a full-grown giraffe — sent back spates of discoveries on the gas giant’s moons, including the observation of a magnetic environment around Ganymede that was distinct from Jupiter’s own magnetic field. The mission ended in 2003, but newly resurrected data from Galileo’s first flyby of Ganymede is yielding new insights about the moon’s environment — which is unlike any other in the solar system.

“We are now coming back over 20 years later to take a new look at some of the data that was never published and finish the story,” said Glyn Collinson, lead author of a recent paper about Ganymede’s magnetosphere at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We found there’s a whole piece no one knew about.”

The new results showed a stormy scene: particles blasted off the moon’s icy surface as a result of incoming plasma rain, and strong flows of plasma pushed between Jupiter and Ganymede due to an explosive magnetic event occurring between the two bodies’ magnetic environments. Scientists think these observations could be key to unlocking the secrets of the moon, such as why Ganymede’s auroras are so bright.

In 1996, shortly after arriving at Jupiter, Galileo made a surprising discovery: Ganymede had its own magnetic field. While most planets in our solar system, including Earth, have magnetic environments — known as magnetospheres — no one expected a moon to have one.

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Oumuamua – What We Are Learning

Remember Oumuamua the interstellar visitor that whizzing through the solar system at over 315,000 km per hour? The thing was kind of strange at first because it wasn’t anywhere near a roundish shape rather it was like a giant spike or chip.

I could imagine this thing being chipped off from a larger object or maybe this was all that was left after such an event. Now there is a new theory and I didn’t see this one coming. Gravity stretching? Yeah, weird. The other thing about Oumuamua is it is giving insight into planetary formation.

Here’s the scoop from NASA – he first interstellar object ever seen in our solar system, named ‘Oumuamua, is giving scientists a fresh perspective on the development of planetary systems. A new study by a team including astrophysicists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, calculated how this visitor from outside our solar system fits into what we know about how planets, asteroids and comets form.

On Oct. 19, 2017, astronomers working with the NASA-funded Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1) at the University of Hawaii spotted an object zipping through our solar system at a very high speed. Scientists at the Minor Planet Center, funded by NASA’s Near-Earth Object Observations Program, confirmed it was the first object of interstellar origin that we’ve seen. The team dubbed it ‘Oumuamua (pronounced oh-MOO-ah-MOO-ah), which means “a messenger from afar arriving first” in Hawaiian — and it’s already living up to its name.

“This object was likely ejected from a distant star system,” said Elisa Quintana, an astrophysicist at Goddard. “What’s interesting is that just this one object flying by so quickly can help us constrain some of our planet formation models.”
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