Starship Asterisk*

Scientists and scholars, astrophysicists and engineers, students and academics will gather next week in 192 countries to be part of Asteroid Day, the official United Nations’ day of awareness and education about asteroids. This year, the fifth anniversary of Asteroid Day, events will focus on the role of asteroids in the formation of our solar system and advances in technology to better detect, track and analyze asteroids and review our ability to deflect a rogue asteroid headed towards Earth. Asteroid Day is a program of Asteroid Foundation, a Luxembourg nonprofit organization.

Asteroid Day is held annually on 30 June, the anniversary of the Earth’s largest asteroid impact in recorded history, the 1908 Siberia Tunguska event. Events are organized year round but the majority of them are scheduled on or leading up to 30 June. Asteroid Day events range from asteroid quizzes in a Dublin bar, to high-level discussions of policy and programs at the National Air and Space Museum in Washington, DC. ...

Abell 370 Parallel Field with Asteroids

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Image Credit: NASA, ESA, and B. Sunnquist and J. Mack (STScI)
Acknowledgment: NASA, ESA, and J. Lotz (STScI) and the HFF Team

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Every year on 30 June, the global “Asteroid Day” event takes place to raise awareness about asteroids and what can be done to protect Earth from possible impact. The day falls on the anniversary of the Tunguska event that took place on 30 June 1908, the most harmful known asteroid related event in recent history.

This week, a team of astronomers, planetary scientists and software engineers based at ESA and other research institutes has launched a new citizen science project: the Hubble Asteroid Hunter. The project was developed as part of the Zooniverse – the world’s largest and most popular platform for people-powered research.

The new project features a collection of archival Hubble images where calculations indicate that an asteroid might have been crossing the field of view at the time of the observation. Everyone can participate! By identifying the asteroids potentially present in these images and marking the exact position of their trails, you too can help the team improve the asteroid orbit determination and better characterise these objects. Precise knowledge of the orbit is particularly important for so-called near-Earth asteroids, those potentially flying close to our planet.

A couple of years ago, while observing distant galaxies lying billions of light-years away, the NASA/ESA Hubble Space Telescope serendipitously spotted several asteroids, small Solar System objects that reside ‘only’ a few tens to hundreds of millions of kilometres from Earth. As seen in this image, the curved or S-shaped streaks in this image are trails created by asteroids as they move along their orbits. Rather than leaving one long trail, the asteroids appear in multiple Hubble exposures that have been combined into one image. This picture was first published in 2017 and shows the parallel field for the galaxy cluster Abell 370, featuring a total of twenty asteroid trails, belonging to seven unique objects.

Asteroids are mainly found in an area called the ‘main belt’, between the orbits of Mars and Jupiter. More than 700 000 asteroids have been identified to date, and predictions indicate that many more might be out there, each left over from the early days when planets were taking shape around the Sun.

Trees flattened by the intense shock wave created in the atmosphere as the space rock exploded above Tunguska on June 30, 1908. The photograph was taken by the Soviet Academy of Science 1929 expedition led by Leonid Kulik. 500,000 acres, the size of a large metropolitan city, were flattened. Flattening trees requires an immense shock wave. World Asteroid Day is held every June 30 as a global awareness campaign where people around the world come together to share knowledge about asteroids and learn how to protect our planet. (Wiki Commons)

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Every single day, many tons of tiny rocks – smaller than pebbles – hit the Earth’s atmosphere and disintegrate. Between frequent shooting stars we wish on in the night sky and the massive extinction-level asteroids that we hope we never see, there is a middle ground of rocks sized to make it through the atmosphere and do serious damage to a limited area. Now, new research from NASA indicates that the impacts of these mid-size rocks may be less frequent than previously thought.

The research revealed that such relatively small but regionally devastating impacts happen on the order of millennia – not centuries, as previously thought. In addition, the new research has pushed forward our knowledge about the complex processes that determine how large rocks from space break up when entering Earth’s atmosphere.

This new research was inspired by a workshop held at NASA’s Ames Research Center in Silicon Valley and sponsored by the NASA Planetary Defense Coordination Office. Their results are published in series of papers in a special issue of the journal Icarus. The theme of the workshop: reexamining the astronomical cold case of the 1908 Tunguska impact event. ...