Special Topic: Comet Tails
Of all the phenomena associated with comets, the one that more than any other gives them their beauty and their mystique is their tails. As recounted in a previous “Special Topics” presentation, the first recorded scientific observation of a comet concerned its tail: when observing the bright comet that appeared during the second half of …
Twin spacecraft to study “rubble pile” binary asteroids
The official go-ahead has been given by NASA to a mission to launch a pair of small spacecraft to capture the first-ever closeup look at a mysterious class of solar system objects: binary asteroids. These bodies are pairs of asteroids that orbit around each other in space, much like the Earth and Moon. In a project …
This Week in History: September 13-19
SEPTEMBER 13, 1959: The then-Soviet Union’s Luna 2 spacecraft impacts the lunar surface slightly to the east of the Mare Imbrium. This was the first human spacecraft to reach the moon and the first spacecraft to impact another object in the solar system. SEPTEMBER 13, 1985: The U.S. Defense Department’s P78-1 satellite is deliberately destroyed …
Comet of the Week: 21P/Giacobini-Zinner 1984e
Perihelion: 1985 September 5.21, q = 1.028 AU The last comet discovered in the 19th Century was found on December 20, 1900, by the French astronomer Michel Giacobini from Nice Observatory, the fifth of twelve comets he discovered between 1896 and 1907. The comet was around 10th magnitude and was followed for two months, with …
Special Topic: Deflection Strategies
A common and persistent theme throughout “Ice and Stone 2020,” and indeed one of the primary reasons the “small bodies” of the solar system are of such high interest in the first place, is the threat they pose to Earth – or, at least, to our civilization and way of life here on Earth – …
Boeing Starliner orbital test flight to ISS targeted for December
As the Boeing team continues to implement hardware and software changes recommended by the joint review team, NASA’s Commercial Crew Program is targeting December for the launch of a second uncrewed test flight of the Boeing CST-100 Starliner spacecraft to the International Space Station. “The Commercial Crew Program currently is targeting no earlier than December …
5 ways families can enjoy astronomy during the pandemic
This is a challenging time for families. Schools across the U.S. are struggling to provide a meaningful online experience. The coronavirus pandemic has cut off or restricted many entertainment options. As an astronomer, I believe a great way for families to fill the void and have a meaningful science experience in the time of COVID-19 …
This Week in History: September 6-12
SEPTEMBER 6, 1618: The German astronomer and mathematician Johannes Kepler observes Comet 1618 I (new style C/1618 Q1) – the first of three “Great Comets” that appeared that year – through a small telescope, the first recorded telescopic observation of a comet. SEPTEMBER 8, 1991: Tom Gehrels with the Spacewatch program in Arizona discovers the …
Comet of the Week: 2I/Borisov I/2019 Q4
Perihelion: 2019 August 8.55, q = 2.007 AU According to our present understanding of how the solar system formed and evolved, all the various comets, including those passing through the inner solar system as well as those in the Kuiper Belt and the Oort Cloud, are the “leftovers” from the planet formation process. Over the …
Special Topic: “Small Bodies” Moons
The “Special Topics” presentation four weeks ago was on the subject of the small moons of the various planets in the solar system. It would seem reasonable to think that the bodies that possess moons don’t stop with the major planets, but that many of the “small bodies” that are the focus of “Ice and …