Special Topic: Great Comets
Few, if any, sights in the nighttime sky are more impressive than that of a bright, long-tailed comet. It is little wonder that our ancestors of just a few centuries ago, who had little idea of what they were actually seeing, were amazed and perhaps even terrified of the sight, and even today the appearance …
Ice and Stone 2020 Word Search #2
Do your best to find these words that are scattered throughout the sixth weekly edition of Ice and Stone 2020. Words may be placed horizontally or vertically. Letters in the grid may be used in more than one word, but not all the letters in the grid have to appear in a word. More from …
NASA prepares robot to traverse beneath oceans of Europa
NASA is planning a mission to look for life on Jupiter’s moon Europa and has created a rover that will be able to navigate its icy surface from above and below. That’s how BRUIE — the Buoyant Rover for Under-Ice Exploration — was born. A nimble and buoyant robot, BRUIE can traverse sheets of ice …
This Week in History: February 16-22
FEBRUARY 17, 1930: A bright meteor appears in the sky above the midwestern U.S. and falls to the ground near Paragould, Arkansas. With a total mass of 370 kg, the Paragould meteorite, a stony chondrite, is the second-largest meteorite fall seen from and recovered in North America. FEBRUARY 17, 1996: The Near-Earth Asteroid Rendezvous (NEAR) …
Comet of the Week: 3D/Biela 1846 II
Perihelion: 1846 February 11.49, q = 0.856 AU The stories of the first two numbered periodic comets, 1P/Halley and 2P/Encke – both of which are future “Comets of the Week” – are well known. The third numbered periodic comet also has an interesting story, but unlike the earlier two, it will likely never be seen …
Special Topic: Stellar Intruders
Five weeks ago I devoted the “Special Topics” presentation to the subject of the Oort Cloud, the large spherical cloud of comets that is believed to enshroud the solar system out to distances of several tens of thousands of Astronomical Units. The comets in the Oort Cloud have been there since the forming Jupiter and …
Solar Orbiter on way to explore Sun’s polar regions
The Solar Orbiter collaborative mission between ESA (European Space Agency) and NASA to study the Sun, its poles, and space weather in unprecedented detail, streaked to space on a commercial United Launch Alliance Atlas V rocket this past weekend from the a rocket range along the Florida coastline. The Solar Orbiter mission started with an …
This Week in History: February 9-15
FEBRUARY 9, 1986: During its most recent return Comet 1P/Halley passes through perihelion at a heliocentric distance of 0.587 AU. Comet Halley’s 1986 return is a future “Comet of the Week,” and its entire history is the subject of a future “Special Topics” presentation. FEBRUARY 10, 1907: August Kopff at Heidelberg Observatory in Germany discovers …
Comet of the Week: PANSTARRS C/2017 T2
Perihelion: 2020 May 4.95, q = 1.615 AU After devoting my “Comet of the Week” last week to the first comet I ever observed, it seems appropriate to devote this week’s “Comet of the Week” to the brightest comet that is currently visible in our nighttime skies, and which is easily accessible for observations, at …
Special Topic: Centaurs
In previous “Special Topics” presentations I have focused on asteroid populations in the “main asteroid belt” between Mars and Jupiter, and on asteroids in near-Earth space. If, however, as is now widely believed to be the case, asteroids are among the “leftovers” of the planet formation process, we would accordingly expect asteroids to exist in …
This Week in History: February 2-8
FEBRUARY 2, 1106: Sky-watchers around the world see a brilliant comet during the daytime hours. In subsequent days it becomes visible in the evening sky, initially very bright with an extremely long tail, and although it faded rapidly it remained visible until mid-March. The available information is not enough to allow a valid orbit calculation, but …
Comet of the Week: Tago-Sato-Kosaka 1969g
Perihelion: 1969 December 21.27, q = 0.473 AU Everyone fondly remembers their “first.” When it comes to comets, my “first” came exactly 50 years ago on Monday evening, February 2, 1970, when I was 11 years old and in the 6th Grade, and involved a 5th-magnitude fuzzball located close to the 2nd-magnitude star Hamal in …
Special Topic: Comet observations from space
All astronomers, be they professional or amateur, or even just casual sky-watchers, have often had to contend with the vagaries of the earth’s atmosphere. Clouds will often get in the way, especially at inopportune times; almost every astronomer can recite stories of important observations that were precluded by cloudy weather. Even if the skies are …
Ice and Stone 2020 Word Search
Do your best to find these words that are scattered throughout the sixth weekly edition of Ice and Stone 2020. Words may be placed horizontally, vertically or even diagonally. Letters in the grid may be used in more than one word, but not all the letters in the grid have to appear in a word. More …
This Week in History: January 26-February 1
JANUARY 26, 1978: The International Ultraviolet Explorer (IUE) spacecraft is launched from Cape Canaveral, Florida. Throughout its 18 years of operations IUE conducted observations of many astronomical objects, including several comets. JANUARY 27, 2016: A team of astronomers led by Tabitha Boyajian of Yale University publishes their paper on the star KIC 8462852 – unofficially …
Comet of the Week: The Daylight Comet of 1910
Perihelion: 1910 January 17.59, q = 0.129 AU In early 1910 the entire world – astronomers and lay public alike – awaited the imminent return of Comet 1P/Halley, which had been recovered the previous September and which was already detectable with moderate-sized telescopes. While Halley would go on to put on a spectacular display around …
Special Topic: Exocomets
It is now generally accepted that the planets in our solar system formed via the accumulation of smaller bodies dubbed “planetesimals” – which in turn formed from the accumulation of dust grains and (in the outer and thus colder regions) gas molecules – early in its history. Due to the early sun’s rotation the infalling …
This Week in History: January 19-25
JANUARY 19, 2006: NASA’s New Horizons mission is launched from Cape Canaveral, Florida. After a somewhat distant flyby of the main-belt asteroid (132524) APL in June 2006 and a gravity-assist encounter with Jupiter in February 2007, New Horizons encountered Pluto and its system of moons in July 2015 – providing our first detailed view of …
Comet of the Week: (6478) Gault
Perihelion: 2020 January 2.79, q = 1.859 AU It has been obvious for several decades that the dividing line between “comets” and “asteroids” is, in a word, nebulous, and some facets of this will be explored in future “Special Topics” presentations. One group of objects that are included within this discussion were initially referred to …
Special Topic: Asteroid (433) Eros
Two weeks ago I devoted the “Special Topics” presentation to the subject of near-Earth asteroids. Up until almost the end of the 19th Century all of the over 400 asteroids that had been discovered up to that time orbited within the “main asteroid belt” between Mars and Jupiter, and the astronomers of that era were …