Skytalk A weekly discussion of what's new and interesting in astronomy with astronomer Derrick Pitts



A weekly discussion of what's new and interesting in astronomy with astronomer Derrick Pitts

Most Recent Episodes

Some Like it Dry

The Atacama desert in Chile is one of the most arid places on the planet – averaging less than one inch of rainfall per year! High altitude, almost constant clear sky, dry air, and lack of light pollution and radio interference due to its remote location make it a premier place to observe the heavens above. Additionally, the subsurface soil is somewhat similar to conditions on Mars. Robotic rovers deployed in the Atacama have found subsurface microbes that are highly resistant to salt. Using a rover-mounted robotic drill and sampling device, soil samples recovered from 80 cm(31 inches) contained unusual and highly specialized microbes that were distributed in patches, which researchers linked to the limited water availability, scarce nutrients and chemistry of the soil. The Atacama desert is the most Mars-like region on Earth. NASA's InSight Lander Mars temperature probe was to be hammered 16 feet into the Martian soil to check internal heat flow as a way to characterize the Martian interior structure, but it jammed last week when the probe encountered unanticipated rock. Signs of Spring: The Vernal equinox is now less than two weeks away, and we spring ahead from Eastern Standard to Daylight Saving Time Sunday. 5:30am marks the start of the pre-dawn 'golden hour' for viewing Venus, Saturn and Jupiter in a line. In the evening: a waxing crescent moon slides higher in the 7 p.m. sky each day On Monday the moon is left of rosey Mars.

Worth the Wait for Weightlessness?

Beth Moses, Astronaut Trainer for Virgin Galactic, flew aboard its latest test flight as its first passenger. The VSS Unity flew into space last week piloted by David MacKay and Mike Masucci. Last week's flight was the first to carry another person besides pilot and co-pilot and its principle objective was to test how the craft would handle during descent with its twin tails rotated upward relative to the fuselage. The altitude achieved, 55.8 miles, is high enough to earn all three crew members commercial astronaut wings from the Federal Aviation Administration. There are more test flights to come this year, but Virgin Galactic's founder Richard Branson would love to make his first flight on the 50th anniversary of Apollo 11's moon landing, with regular flights possibly beginning late this year. The first woman to fly in space, Valentina Tereshkova, celebrates a birth anniversary this week on Wednesday. She was born in 1937. It was her expertise in skydiving that led to her selection. The then-26-year-old was selected from among a group of five women to fly on 16 June 1963. She completed 48 earth orbits over almost three days. Now honored as a hero in Russia, Tereshkova is the only woman to have flown in space on a solo mission.

Volunteers Needed for Stellar Sleuthing

Wanna get your hands dirty in astronomy? Backyard Worlds: Planet 9 is a newly revised version of a Zooniverse Citizen Scientist data-mining project for finding nearby failed stars and exoplanets created through a collaboration of a number of research agencies including NASA, NOAO, AMNH, STSci, ASU, UCSD, and others. The project, done by human searches through a new double-size data set, depends on the acuity of the human eye to discern differences between data and noise in digital images. There are enormous mountains of data to go through, far more data than can be examined by individual astronomers in any reasonable amount of time and significant discoveries can be made by amateur researchers. So-called stellar streams are associations of stars; typically a globular cluster or a dwarf galaxy orbiting a galaxy that has been stretched out along its orbit and torn apart by tidal forces. There are 18 known streams in our Milky Way galaxy, one of which is a mere 330 light years from Earth. Since it's close enough for astronomers to measure its stellar members precisely, we can get better estimate of our galaxy's true mass because we can use the stream's motion to measure the gravitational pull of our galaxy on it. LOFAR Survey reveals hundreds of thousands of previously unmapped galaxies Low frequency radio telescope array is spread across northern Netherlands and nearby countries have surveyed 25% of the sky and the first 10% of data is now available for study, revealing the existence of 100,000 galaxies that were previously unseen. This detection system is different from a visible light survey which only shows the visible light component of an object in space. Observing in other frequencies, like radio, reveals additional processes and details otherwise unknown, resulting in an incomplete picture of the universe's operation. Night Sky highlights this week: Wednesday thru Saturday morning around 5:45 , a waning crescent moon slides past Jupiter, Saturn, then Venus in that order. Mars is quite high in the west, southwest and still stunningly bright!

A Conversation With Dr. Hakeem Oluseyi

Earlier this week, the Franklin Institute Night Sky Observatory program featured special guest Dr. Hakeem Oluseyi, astrophysicist, inventor, and co-host of the Science Channel's Outrageous Acts of Science to focus on some of the most perplexing paradoxes of the universe, the possibility of life on other planets, and why he believes his unlikely personal path can inspire the next generation of scientists. He stopped by WHYY studios to join the conversation with WHYY's Dave Heller and Derrick Pitts, Chief Astronomer at the Franklin Institue. Oluseyi was born in New Orleans, Louisiana. After his parents divorced when he was four years old, he and his mother lived in some of the country's toughest neighborhoods including the 9th Ward of New Orleans; Watts, Los Angeles, California; Inglewood, California; South Park, Houston, Texas; and Third Ward, Houston, Texas before settling in rural Mississippi a month before Oluseyi turned 13 years old. He completed middle school and high school in the East Jasper School District graduating as his high school's valedictorian in 1985. Oluseyi served in the U.S. Navy from 1984 to 1986, and then enrolled in Tougaloo College where he earned Bachelor of Science degrees in physics and mathematics. He earned MS and Ph.D. degrees in physics from Stanford University. His best known scientific contributions are research on the transfer of mass and energy through the Sun's atmosphere, the development of space-borne observatories for studying astrophysical plasmas and dark energy, and the development of transformative technologies in ultraviolet optics, detectors, computer chips, and ion propulsion. However, he values inspiring others to strive over his personal accomplishments, as evidenced by his tweet; "Positively impacting lives and communities through education gives me greater satisfaction than any scientific discovery or invention I've ever made" Oluseyi appears as a commentator and scientific authority on Science Channel television shows including How the Universe Works, Outrageous Acts of Science, and Strip the Cosmos. His TED Talks include the topics "Infinity explained in three minutes" and "How we know; the big bang." With favorable viewing conditions; Saturn will appear just below Venus tomorrow morning. On Monday, they will be next to each other, then they switch places and Saturn will be above Venus with Venus heading down toward the sun. Mars still dominates the evening sky but Uranus is lurking right next door below towards the horizon.

What's in a Shape?

Astronomers at the National Astronomical Observatories of the Chinese Academy of Sciences have detected that our Milky Way galaxy, while shaped like a big disk that rotates, is actually warped at the outer edges. The warping causes our galaxy to have a turned up lip at one end and a turned down lip at the opposite edge – like a 'bit of a twisted 'S' shape'. It's theorized that warping seems to be caused by torque induced by the rotation of the inner disk of the galaxy. Still great planet viewing in the pre-dawn sky. Winter constellation Orion is surrounded by the Winter Circle: Auriga, Gemini, Canis Minor, Canis Major and Taurus.

Strolling Our Galactic Neighborhood

Our Milky Way is one of some forty galaxies that comprise what is known as our "local group." Two of our nearest galactic co-occupants are the Large and Small Magellanic Clouds (visible in the Southern Hemisphere). At a mere 170,000 light years away, they are close enough for astronomers to notice that, contrary to expectation, they are producing stars at an increasing rate, in contrast to our Milky Way where star production has been decreasing for billions of years. It's thought that the much more massive Milky Way exerts a strong gravitational pull that is the driving force behind the increased star production. Separately, that gravitational tug will ultimately lead to a merger of the three galaxies in some 2.5 billion years. What's not known is what effect this could have on our sun and its planets. The sun is not expected to begin its evolution toward a red giant stage for another 2.5 billion years after the galaxy merger.

Lunar Eclipse Beckons

Despite the forecasted blast of arctic air heading our way Sunday – bundle up and brave the cold because the next opportunity to take in a spectacular full lunar eclipse won't come until May 2022 ! Spanning late Sunday into early Monday – this will be the first time since 1975 that a total lunar eclipse coincides with a holiday weekend. The period of totality when Earth's shadow blocks out the moon extends from 11:41pm Sunday until 12:43am Monday. Derrick explains why this eclipse is popularly (but inaccurately) referred to as "the blood moon" and "the super moon." If cloud cover blocks the spectacle, will webcast the event from Northern California. Cotton is growing on the Moon . . albeit, inside the Chinese lander Chang'e 4. This marks the first time that seeds have sprouted on another world. Two other plant variety seeds (potato and Arabidopsis) haven't sprouted yet, but scientists are holding out hope! In addition to Sunday's Lunar Eclipse, this week also features a great opportunity to take in Winter Circle of constellations and bright stars. Also, Venus slides past Jupiter in the pre-dawn sky this week. Mars can be spotted in the southwest sky every clear evening after sunset.

Speed Kills

The more scientists learn about black holes, the more the findings confirm the warning: Speed kills. The black hole ASASSN-14li lies at the heart of a galaxy 290 million light-years away from Earth and harbors between 1 million and 10 million times the mass of the sun. That makes it about as hefty as the black hole at our Milky Way galaxy's core, known as Sagittarius A*, which contains about 4 million solar masses. Focusing on ASASSN-14li, astronomers at MIT just announced a new way to measure the rotation of black holes: Look for the remnants of partially consumed stars as regular pulses of x-rays as the star spins around with the black hole's spin. In this case, the 'pulse' recurred every 131 seconds for 450 days; and with that, it was determined that the black hole spins at 50% of the speed of light (186,000 miles / second). More info here. A new study confirms an earlier claim that the cores of white dwarf stars eventually crystallize as they cool. Crystallization as a diamond comes because the core of many white dwarf stars is composed on oxygen and carbon, the essential ingredients in diamond composition. The thinking is that as the core cools below 18 million degrees, the crystallization begins converting the core into solid oxygen and carbon or diamond. Thinking about staking a claim? Good luck! These stars are very dim, not to mention their distance and the logistics involved in an attempt to mine something like this. But wait, there's hope: Our sun is predicted to go diamond in about 10 billion years. Clear dark sky highlights: Venus and Jupiter dominate the pre-dawn sky this coming week. Mars and the moon are next to each other tonight.

Ultima Thule

NASA's New Horizons spacecraft continues its sojourn through the outer reaches of our solar system. For the next 20 months, it will transmit data back to earth gathered from its passby of the planetessimal Ultima Thule, a snowman-shaped object around 20 miles in length. At a distance of 4.1 billion miles from Earth, it takes more than six hours (traveling at the speed of light) for that information to reach us. Ultima Thule resides in the center of the vast Kuiper Belt, home to frozen remnants from the birth of the solar system. NASA launched the nuclear-powered spacecraft 13 years ago, and traveling at 32,000 miles per hour, it will take New Horizons an additional eight or nine years to bid adieu to the Kuiper Belt and enter interstellar space. At one billion miles beyond Pluto (visited by New Horizons in 2015), this marks the most distant flyby of an object in our solar system. Nancy Grace Roman, NASA's first chief of astronomy and first leader of the effort to create Hubble Space Telescope died last week at the age of 93. She embarked on her career at NASA in 1948. Turning to the night sky: A New Moon today means optimal viewing this week if the cloud cover cooperates; Venus and Jupiter can be seen from 6:00a – 6:30a, Mars is available in the evening sky. Wednesday morning at 6:11, International Space Station pops into view in the North/Northwest and sails across the Northern sky into the East by 6:16am. The next morning (Thursday) at 5:21, NE, ISS can first be spied in the North East, and sails out to the east just under the brilliant star VEGA, then on to the South East horizon by 5:25am.

Going, Going, Gone

Enjoy them while you can, because according to a new analysis of data from the Keck 10 meter telescope at Mauna Kea, Saturn's rings are eroding away. Data gathered 10 years ago by Voyager space probes indicated that the water ice particles that make up Saturn's ring system were being pulled out of the rings and spiraling down magnetic field lines from the inner edge of the rings to the planet. Given how quickly the rings seem to be deteriorating, the rings probably haven't been around more than 100 million years. Think of it this way; the dinosaurs only got to see the rings for around the first 35 million of those 100 million years before they died out. 50 years ago astronauts Jim Lovell, Frank Borman, and Bill Anders left Earth on Apollo 8 for their historic circumnavigation of the moon. With that, they became the first humans to enter the gravitational sphere of influence of another celestial body. Not only was the mission the most important precursor to the first human landing just seven months later, but it was also the mission that gave us on Earth the most riveting view and most thorough definition of our 'Spaceship Earth' via the now iconic 'Earthrise' image. The crew orbited the Moon ten times over the course of 20 hours, during which they made a Christmas Eve television broadcast in which they read the first ten verses from the Book of Genesis. At the time, the broadcast was the most watched TV program ever. Given the dearth of daylight during this solstice season, there is plenty to be seen overhead: In the pre-dawn sky, from 6:00a – 6:30a, Venus, Jupiter, Mercury. Then after sunset – Mars can be spotted in the southwest.

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