20 episodes

A weekly discussion of what’s new and interesting in astronomy with Dr. Derrick Pitts

Skytalk WHYY

    • Natural Sciences

A weekly discussion of what’s new and interesting in astronomy with Dr. Derrick Pitts

    Cold Snap Up North

    Cold Snap Up North

    NASA’s InSight Mars lander keeps daily records of weather conditions at the Elysium Planitia landing site on the red planet. Last week saw daytime highs from 8 to 15 degrees Fahrenheit; lows fell to -139 degrees.

    Seasons are twice as long on Mars as on Earth because the Martian year is 687 days; almost double an Earth year.

    Mars doesn’t have months like we have months though. Our concept is based on a lunar orbit. Mars’ moons orbit much faster – Phobos every 8 hours, Deimos every 30 hours; so well over 2,000 orbits per 30 day ‘month’ for Phobos and over 500 orbits per ‘month’ for Deimos.

    InSight landed Nov. 2018 on a two-year mission to better understand the interior of Mars using both surface and drilling geophysical sensors.

    Turning to night sky highlights this week:

    Mars, Jupiter, and Saturn have the morning sky at 6:00 a.m.; Venus has the evening at 6:00 p.m. We’re gaining 2.5 minutes of sunlight per day through March.

    • 6 min
    Older than Dirt

    Older than Dirt

    Stardust discovered in a meteorite that landed in Australia more than 50 years ago is up to three billion years older than our solar system.

    These remnants are left over from ancient stars that populated this region of the galaxy prior to the birth of our sun, some 4.5 billion years ago.

    These particles got swept up in planet formation and/or hitched a ride to Earth on asteroids that have been in circulation ever since.

    Dating was determined from an element, Neon-21, which is derivative of cosmic ray-bombarded silicon carbide.

    Higher proportion of Neon-21 indicates the silicon carbide was drifting in space for a very long time before being embedded in a hunk of our solar system’s detritus left over after the solar system formed. The discovery may yield new insight into star formation in the Milky Way.

    Turning to the night sky – Mars, Jupiter, and Saturn are still aligned in the 6:00 am predawn sky in the east.

    They’re sliding closer together over the next few weeks.

    Venus till dominates the southwest evening sky and will be joined by a thin waxing crescent moon on Wednesday.

    Darker skies where you are? Tonight and tomorrow night, between 7:00 pm and 8:00 pm, try looking for the Andromeda galaxy with your binoculars halfway up above the horizon in the just north of west. It will resemble a faint smudge of softly glowing sky.

    • 8 min
    Taking a Telescope to Galileo

    Taking a Telescope to Galileo

    Today is Galileo’s 456th birth anniversary. His iconoclastic reputation overshadows his basic raison d’etre at the time – to make a buck. He was a struggling teacher who worked in the ‘gig economy’ of Renaissance Italy. Galileo wasn’t born to a high place in society; he wasn’t a politician, his parents were not rich and his father actually wanted his son to become a physician. He really wanted to be a mathematician. He eventually ditched medical school and became a university math instructor where he began to investigate physics of motion.

    A colleague informed him of a new optic device he’d seen. After a bit of research, Galileo figured out how others were making these new optic devices and using his math skills, made a better one. He immediately saw the how this invention could get him hired by a wealthy and influential patron to whom he sold the manufacturing rights. He got a better university appointment and didn’t have to teach classes, so he could pursue his research interests.

    Fast Radio Bursts, or FRBs (first detected in 2007) are intermittent, ubiquitous, low frequency, very high energy, speedy pulses of radio energy. They are considered unusual because of the power – very intense and very brief – just milliseconds – and seemingly from billions of light years away – translate as from very far off, hence very old. To date only a few dozen have been seen but their origin is a mystery.

    Recently, astronomers using a Canadian radio telescope have found one with a repeating 16-day pattern and have pinpointed its point of origin in a relatively nearby spiral galaxy. First, astronomers have several possibilities they refer to for origin of phenomena like this but these FRBs don’t fit the pattern of any of the known source types. Second, they are very energetic and seem to come from outside our galaxy, sometimes from halfway across the universe. Being so bright the source phenomena must be powerful because the FRBs outshine any other source in the sky except the sun – albeit for just a millisecond.

    The mystery of the mechanism that creates these has been compounded by the repeating pattern. Sometimes that’s a result of rotation as in rotating neutron stars or pulsars. Maybe there’s some kind of unusual energetic interaction between black holes and neutron stars in a rotating galaxy setting that accounts for the regularity. We don’t know.

    Starting on Sunday morning and all this week at 6:00 am, the Moon, Mars, Jupiter, and Saturn will appear in a diagonal line upper right to lower left; the moon marches past each planet starting Monday – Tuesday at Mars, Wednesday above Jupiter, Thursday at Saturn, done by Friday.

    If you catch Venus and Mercury tonight (or tomorrow night) – best seen between 6:15 pm and 6:20 pm, you’ll have seen all five visible planets in one day!

    • 10 min
    Coming Attractions

    Coming Attractions

    Astronomers observing white dwarf stars see spectrographic signatures of previously orbiting gas giant planets. Our gas giants (Jupiter and Saturn) will possibly do the same – leave signatures of their existence on our White Dwarf sun long after all the inner planets are gone and the outer planets are transformed. Not to worry – this won’t happen for some eight billion years.

    Bid adieu to the Spitzer Space Telescope! Named after astrophysicist Lyman Spitzer (in 1965 he first proposed what would later become the Hubble Space Telescope), the Spitzer Space Telescope was launched in 2003. Expected to last just 2.5 years, Spitzer continued generating good science results until it was finally turned off last month (after it ran out of coolant), an amazing 16 years after it launched. Dusty stellar nurseries, extrasolar planets, centers of galaxies, and newly forming planetary systems hidden behind thick curtains of cosmic dust would remain unseen without Spitzer’s unique heat-detecting capability.

    From 6:15 a.m. – 6:30 a.m., Jupiter, Mars, Saturn, and the bright star Antares are all visible.

    In the west at 6:00 p.m., bright Mercury is at its greatest height for this cycle. A clear view of the horizon and binoculars will help you catch it.

    • 7 min
    49ers, Chiefs & Punxsutawney Phil

    49ers, Chiefs & Punxsutawney Phil

    49ers, Chiefs & Punxsutawney Phil

    This Superbowl Sunday coincides with Groundhog Day – the first cross-quarter day of 2020 (half-way between winter and spring). Punxsutawney Phil may be the most famous groundhog in the U.S., but he isn’t the most accurate. The four-legged creature only has a 39 percent accuracy, according to Stormfax Almanac’s data. Phil sees his shadow about 85 percent of the time (which portends six more weeks of winter)

    Extreme Global Warming! – Different process altogether from Earth.

    KELT-9b is a gas giant planet orbiting a star 670 light years away from earth. As a ‘hot Jupiter’, it orbits so close to its sun, it’s temperature is very very high. How high? Highest ever recorded for a planet – 7800 degrees Fahrenheit! So high that molecules of Hydrogen gas are torn apart; they can recombine on the night side of the planet.

    A year is 1.5 days, tidally locked so one side NEVER sees daylight. Weird, right?

    The Night Sky

    Our own gas giant Jupiter pokes its head into our 6:15 am predawn sky this week in the South East along with Mars (higher up) and Antares, a little further to the right of Mars.

    Saturn’s tracking a little behind Jupiter but not high enough to catch before sunrise – just yet.

    Venus rules the west however at 6:00 pm, the tiny but bright Mercury is sneaking up from the west a bit each day, reaching up toward Venus.

    • 5 min
    Our Stellar Neighbor Beckons

    Our Stellar Neighbor Beckons

    The dim red star Proxima Centauri, 4.2 lightyears from Earth, is known to have an EarthPlus-planet in the star’s habitable zone. Now a second planet has been detected, but this one is 5.8 times the mass of our planet and orbits its star only once every five years. Unfortunately, it’s also too far from the cool star to be warm enough for liquid water. So, it’s not habitable – at least for us.

    Which leads to a proposal to send 1,000 tiny spacecraft – really just a computer chip attached to a solar sail driven by ground-based lasers with 100 gigawatts of power to drive them along. The idea is that the tiny chips, with so little mass, could be driven up to 15-20% of the speed of light, making the 4.2 light year trip in just 20-30 years. Initial funding of $100 million comes from Russian Yuri Milner, backed by Mark Zuckerberg and Stephen Hawking.

    –When totaling up all the matter in the universe, cosmologists believe that about 80% of the mass of the universe is completely unseen dark matter, 21% is dark energy and just 4% is all the actual matter of the universe. According to all the mass of the universe that can be accounted for, the universe’s rate of expansion, left over after the universe’s inflation period, should indicate a gradual decrease in that expansion rate – the expansion should be slowing. But it isn’t. In fact, it’s accelerating!

    To compensate, cosmologists have introduced the concept of dark energy – an unseen and undetectable force that seems to be pushing clusters of galaxies apart. If the expansion push is totaled up across the universe, the result accounts for the rate of expansion now seen in the universe. Now the basic premise behind dark energy, the unseen force that seems to be driving the universe’s increasing expansion rate, has a serious flaw related to how distance around the universe is determined.

    If that discrepancy cannot be resolved, it may be that dark energy isn’t a piece of the cosmic puzzle at all.

    The new observations haven’t been widely accepted and the results have to be tested by other research teams. Stay tuned.

    The Moon and Mars are visible early this week in the 6:15 – 6:30 a.m. window in the East. Jupiter is now very low in the east at 6:30 a.m. Yes, that’s Venus in the south-west after sunset. It’ll be there for a few months, getting brighter and higher.

    • 9 min

Top Podcasts In Natural Sciences

Listeners Also Subscribed To

More by WHYY