Space Stories: Dinosaur Dust, Missing Stars, and SETI Signals

Posted on by onespaceman2000
Image (Credit): The end of the dinosaurs. (NYT, Roger Harris/Science Source)

Here are some recent stories of interest.

—Royal Observatory of Belgium: “Dust Played a Major Role in Dinosaur Demise“

Fine dust from pulverized rock generated by the Chicxulub impact likely played a dominant role in global climate cooling and the disruption of photosynthesis following the event. This is suggested by a new study published in Nature Geoscience, in which researchers Cem Berk Cenel, Özgür Karatekin and Orkun Temel of the Royal Observatory of Belgium contributed.

—Express: “Astronomers Trying to Unravel Mystery of Three Stars that Suddenly Disappeared from Sky“

A team of Spanish astronomers is leading the investigation into one of stargazing’s most perplexing mysteries. Three bright stars photographed in the night sky above southern California in 1952 vanished just an hour later. Generations of scientists have sought to explain the rare phenomenon over the past half-century, but nothing has yet convinced the community. Researchers at the Centre for Astrobiology (CAB) in Madrid tried to solve the riddle of the “triple transient” that has “remained absent from telescope exposures for 71 years” in a new paper published online.

—Sci.News: “New Study Sets Clearer Bounds on Search for Technosignatures from Extraterrestrial Intelligences“

A stable-frequency transmitter with relative radial acceleration to a receiver will show a change in received frequency over time, known as a ‘drift rate.’ For a transmission from an exoplanet, astronomers must account for multiple components of drift rate: the exoplanet’s orbit and rotation, the Earth’s orbit and rotation, and other contributions. Understanding the drift rate distribution produced by exoplanets relative to Earth, can help scientists constrain the range of drift rates to check in a Search for Extraterrestrial Intelligence (SETI) project to detect radio technosignatures, and help them decide validity of signals-of-interest, as they can compare drifting signals with expected drift rates from the target star. In a new study, University of California, Los Angeles astronomer Megan Grace Li and colleagues modeled the drift rate distribution for over 5,300 confirmed exoplanets, using parameters from the NASA Exoplanet Archive.

A Day in Astronomy: Flyby of Asteroid Gaspra

Posted on by onespaceman2000
Image (Credit): Asteroid Gaspra as photographed by the Galileo spacecraft. (NASA)

On this day in 1991, NASA’s Galileo spacecraft conducted a flyby of asteroid Gaspra, an asteroid that orbits in the asteroid belt between Mars and Jupiter. The asteroid is about 10.5 miles long. Gaspra was discovered in 1916 by Russian astronomer G. N. Neujmin, who named it after a famous Russian spa retreat in Crimea.

The Galileo spacecraft’s primary mission was to visit Jupiter and its moons, but it also conducted other observations along the way, including flybys of asteroids Gaspra and Ida.

Here are a few facts about the Galileo mission from NASA:

  • Galileo was the first spacecraft to orbit an outer planet.
  • It was the first spacecraft to deploy an entry probe into an outer planet’s atmosphere.
  • It completed the first flyby and imaging of an asteroid (Gaspra, and later, Ida).
  • It made the first, and so far only, direct observation of a comet colliding with a planet’s atmosphere (Shoemaker-Levy 9).
  • It was the first spacecraft to operate in a giant planet magnetosphere long enough to identify its global structure and to investigate its dynamics.

Pic of the Week: Get Ready for Halloween!

Posted on by onespaceman2000
Image (Credit): View of Jupiter taken by the NASA’s Juno mission. (NASA/JPL-Caltech/SwRI/MSSS, Vladimir Tarasov)

NASA has an image for all of us just in time for Halloween. The strange face you see above is a view of Jupiter taken on September 7, 2023 by NASA’s Juno spacecraft on its 54th close flyby of the planet.

NASA explains what you are seeing in this northern region of Jupiter:

The image shows turbulent clouds and storms along Jupiter’s terminator, the dividing line between the day and night sides of the planet. The low angle of sunlight highlights the complex topography of features in this region, which scientists have studied to better understand the processes playing out in Jupiter’s atmosphere.

Now I want to see the images from the first 53 flybys to understand what we might have missed.

Space Stories: Distant Spacecraft Updates, Lucy Gets Ready for a Flyby, and Lunar Near-Earth Asteroids

Posted on by onespaceman2000
Image (Credit): Voyager II spacecraft instruments. (NASA)

Here are some recent stories of interest.

—Space.com: “NASA’s interstellar Voyager Probes Get Software Updates Beamed from 12 Billion Miles Away“

About 46 years after NASA’s Voyager 1 and Voyager 2 launched on an epic journey to explore space, the probes’ antique hardware continues to receive tweaks from afar. One update, a software fix, ought to tend to the corrupted data that Voyager 1 began transmitting last year, and another set aims to prevent gunk from building up in both spacecraft’s thrusters. Together, these updates intend to keep the spacecraft in contact with Earth for as long as possible.

—NASA: “NASA’s Lucy Spacecraft Preparing for its First Asteroid Flyby“

NASA’s Lucy spacecraft is preparing for its first close-up look at an asteroid. On Nov. 1, it will fly by asteroid Dinkinesh and test its instruments in preparation for visits in the next decade to multiple Trojan asteroids that circle the Sun in the same orbit as Jupiter. Dinkinesh, less than half a mile, or 1 kilometer, wide, circles the Sun in the main belt of asteroids located between the orbits of Mars and Jupiter. Lucy has been visually tracking Dinkinesh since Sept. 3; it will be the first of 10 asteroids Lucy will visit on its 12-year voyage. To observe so many, Lucy will not stop or orbit the asteroids, instead it will collect data as it speeds past them in what is called a “flyby.”

—UC San Diego: “How Could a Piece of the Moon Become a Near-Earth Asteroid? Researchers Have an Answer“

A team of astronomers has found a new clue that a recently discovered near-Earth asteroid, Kamooalewa, might be a chunk of the moon. They hypothesized that the asteroid was ejected from the lunar surface during a meteorite strike–and they found that a rare pathway could have allowed Kamooalewa to get into orbit around the sun while remaining close to the orbits of the Earth and the Moon. The research team details their findings in the Oct. 23 issue of the journal Nature Communications Earth & Environment. Kamo`oalewa has been the object of several astronomy studies in recent years. As a result, a Chinese mission launching in 2025 is set to land on the asteroid and return samples to Earth.

Speaking of Soil Samples…

Posted on by onespaceman2000
Image (Credit): Apollo 17 commander Eugene Cernan approaching the Lunar Roving Vehicle. (NASA)

In addition to the asteroid Bennu sample, a lunar sample from 1972 is also grabbing headlines. It appears that the lunar sample collected by the Apollo 17 crew indicates the Moon may be about 40 million years older than previously believed.

In a study published in the journal Geochemical Perspectives Letters, titled “4.46 Ga Zircons Anchor Chronology of Lunar Magma Ocean,” states (in part):

The atomic spatial resolution analysis of individual mineral grains demonstrates the absence of nanoscale clustering of lead, which supports a 4.46 Ga ancient formation age for lunar zircon in sample 72255. This age pushes back the age of the first preserved lunar crust by ∼40 Myr and provides a minimum formation age for the Moon within 110 Myr after the formation of the solar system.

If you can forgive the title of the piece, it basically resets the understanding of the Moon’s formation and, thereby, the formation of the early Earth.

In a Reuters story, Cosmochemist Philipp Heck, senior director of research at the Field Museum in Chicago and senior author of the study, noted:

The giant impact that formed the moon was a cataclysmic event for Earth and changed Earth’s rotational speed. After that, the moon had an effect on stabilizing Earth’s rotational axis and slowing down Earth’s rotational speed…The formation date of the moon is important as only after that Earth became a habitable planet.

What will we still be learning about asteroid Bennu in 50 years (assuming we can get all of that soil out of the canister)?