Obscure Astronomical-Related Terms

Many words have been dedicated to the English language, and some to astronomy itself! We all know this as a fact, but some astronomy-related terms are lesser known than others, and this article is dedicated to them. In the first list, all words below are courtesy the Grandiloquent Dictionary. Definitions provided by them; copyright Grandiloquent Dictionary.

achluophobia -( ) A fear of darkness or of the night 

astrophobia -( ) The fear of stars 

barophobia - ( ) Fear of gravity

heliolater - ( ) A sun worshipper  

heliophobia - ( ) The fear of the Sun  

heliotropism - ( ) The tendency of plants to turn towards the sun  

hemeralopia - ( ) Only being able to see at night  

hemeraphonia - ( ) Able to speak only at night 

lygophobia - ( )A fear of darkness or of the night

myctophobia - ( )  A fear of darkness or of the night

nychthemeron - ( )  A period of 24-hours

phengophobia - ( ) The fear of the Sun or of sunlight 

raith - ( )  A quarter of a year 

scintillation - ( )  The twinkling of stars or small bursts of light 

selenocentric - ( )  One whose life revolves around the moon 

selenography - ( )  The science of geography of the moon 

selenomancy - ( ) Divination using the moon 

selenophobia - ( )  A fear of the moon

Below, more astronomical-related obscure terms are listed, although not necessarily from the Grandiloquent Dictionary.These are words from Dictionary.com and SeaSky Astronomical Dictionary.

Syzygy An alignment of three celestial objects, as the sun, the earth, and either the moon or a planet 

Azimuth the arc of the horizon measured clockwise from the south point, in astronomy, or from the north point, in navigation, to the point where a vertical circle through a given heavenly body intersects the horizon.

Ephemeris a table showing the positions of a heavenly body on a number of dates in a regular sequence.

Protoplanet the collection of matter, in the process of condensation, from which a planet is formed.

Zenith the point on the celestial sphere vertically above a given position or observer. 

Node either of the two points at which the orbit of a heavenly body intersects a given plane, especially the plane of the ecliptic or of the celestial equator. 

Facula an irregular, unusually bright patch on the sun's surface.

achrondite A stone meteorite that contains no chondrules.

Apastron the point at which the stars of a binary system are farthest apart (periastron).

Catena A series or chain of craters.

Ejecta Material from beneath the surface of a body such as a moon or planet that is ejected by an impact such as a meteor and distributed around the surface. Ejecta usually appear as a lighter color than the surrounding surface.

Granulation one of the small, short-lived features of the sun's surface that in the aggregate give it a mottled appearance when viewed with a telescope.

Hypergalaxy A system consisting of a spiral galaxy surrounded by several dwarf white galaxies, often ellipticals. Our galaxy and the Andromeda galaxy are examples of hypergalaxies.

Libration An effect caused by the apparent wobble of the Moon as it orbits the Earth. The Moon always keeps the same side toward the Earth, but due to libration, 59% of the Moon's surface can be seen over a period of time.

Nadir the point on the celestial sphere directly beneath a given position or observer and diametrically opposite the zenith.

Obliquity The angle between a body's equatorial plane and orbital plane.

Planemo A large planet or planetary body that does not orbit a star. Planemos instead wander cold and alone through the cosmos. It is believed that most planemos once orbited their mother star but were ejected from the star system by gravitational interaction with another massive object.

Is Vesta the Smallest, Terrestial Planet?

Video Courtesy of NASA.

The New Vesta: Dawn Spreads the Asteroid's Secrets

O beautiful Vesta! Vesta has become quite a spectacular asteroid, not only because of its beauty (as you can see in the image below), but becasue of everything Dawn has sent us so far. After Dawn reached asteroid 4 Vesta this past weekend, continual pictures and information has been sent to our planet. Vesta isn't just any old asteroid.

Isn't the protoplanet beautiful?! Dawn sure thinks so! Vesta is the second most massive object in the asteroid belt, with Ceres being the first, so it's a big deal to see such wonderful surface features on this asteroid. Ground-based telescopes have been trying to get a good picture of Vesta forever, but nothing was as good until Dawn arrived.

"We are beginning the study of arguably the oldest extant primordial surface in the solar system," said Dawn principal investigator Christopher Russell from the University of California, Los Angeles. "This region of space has been ignored for far too long. So far, the images received to date reveal a complex surface that seems to have preserved some of the earliest events in Vesta's history." No spacecraft has ever visited the asteroid belt before, so this is a first for the whole earth. NASA has accomplished much, but nothing this significant yet. It was the first space exploration group to launch a craft to visit the asteroid belt, which is very impressive.

Here, you can view Vesta's size relative to other major asteroid bodies in the asteroid belt. Click on the picture to make it larger; if you can't do that: 21 Lutetia is on top (very massive), two under that is 243 Ida and moon Dactyl, and under that is 433 Eros, just naming the famous, well-known asteroids.

As people are still in awe of Dawn's arrival after traveling over 1.7 billion miles for four years, you have to admit Dawn did make good time. Being the first spacecraft to ever make the largest propulsive acceleration of any spacecraft, Dawn made a change of velocity of more than 4.2 miles a second, on account of its high-tech ion-powered engines.

"Dawn slipped gently into orbit with the same grace it has displayed during its years of ion thrusting through interplanetary space," said Marc Rayman, Dawn chief engineer and mission manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It is fantastically exciting that we will begin providing humankind its first detailed views of one of the last unexplored worlds in the inner solar system."

Dawn will keep on approaching Vesta for about three weeks, looking for hypothetical moons, observing surface features and properties. NASA writes, "In addition, navigators will measure the strength of Vesta's gravitational tug on the spacecraft to compute the asteroid's mass with much greater accuracy than has been previously available. That will allow them to refine the time of orbit insertion."

Dawn will leave Vesta in July 2012, making its way to minor-planet 1 Ceres in February of 2015. More of Dawn is here, along with Dawn's 'journal.' More of Dawn at Astronomical Events Calender is Here.

Dawn and Vesta Now to Unite July 15

After predicting the NASA spacecraft Dawn to reach asteroid 4 Vesta on July 16, NASA realized that Dawn will reach its destination earlier than before, (just by a matter of time zones and location). After being launched in September of 2007, NASA has waited almost four years for their beloved spacecraft to reach this forbid world, for the sole purpose of investigating the earliest part of the solar-system's history.

Dawn's purpose is described more in our May article entitled 'Dawn Presents its First Pictures on Approach to Asteroid 4 Vesta,' but in summary, Dawn is supposed to study this space rock in order to accumulate more information on the earliest stages of our solar system, which is the asteroid belt. Vesta is a protoplanet; or a planet which is a minor planet: one that could have been one, but is just too small. On July 9, Dawn took this photo of Vesta. Although the picture was on NASA's site, each picture there is supposed to represent 2.4 miles, or 3.8 kilometers.

According to those at NASA, Dawn is supposed to enter orbit around 1 am EDT Saturday morning, here on the east coast. It was moved to the 15, just for the Pacific coast, etc. "When Vesta captures Dawn into its orbit, engineers estimate there will be approximately 9,900 miles (16,000 kilometers) between them. At that point, the spacecraft and asteroid will be approximately 117 million miles (188 million kilometers) from Earth," NASA's statistics reflect.

"It has taken nearly four years to get to this point," said Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Our latest tests and check-outs show that Dawn is right on target and performing normally." The Dawn team will calculate the exact time of orbit as the craft gets closer, but as of now, Dawn is almost there!

"Launched in September 2007, Dawn will depart for its second destination, the dwarf planet Ceres, in July 2012. The spacecraft will be the first to orbit two bodies in our solar system," Jet-Propulsion Laboratory (NASA) closes. Celebrate as Dawn enters Vesta's orbit, whether it be the 15 or 16 of July! Dawn has come a long way! Go Dawn!

Dawn Presents Its First Pictures on Approach to Asteroid 4 Vesta

‘A Journey to the Beginning of Our Solar System,’ gracefully rests under the title at the Dawn Mission’s main page at NASA’s Jet Propulsion Laboratory. Explained in an article entitled Dawn: NASA Fact Sheet, that puzzling slogan is interpreted: “Exploring a new frontier, the Dawn mission will journey back in time over 4.5 billion years to the beginning of our Solar System...how is this possible?...thousands of small bodies orbit the Sun [between Mars and Jupiter]...They formed at the same time and in similar environments as the bodies that grew to be the rocky planets (Mercury, Venus, Earth, and Mars). Scientists theorize that the asteroids were budding planets and never given the opportunity to grow...” Although this mission is based on the evolutionist worldview, Dawn will still collect information about these ‘minor planets’ and report back to earth, whether biased or not. Actually, in the article, Dawn: A mission in development forexploration of main belt asteroids Vesta and Ceres, Dawn’s mission is stated clear and more simpler: “Dawn is on development for a mission to explore main belt asteroids in order to yield insights into important questions about the formation and evolution of the solar system.” This sums up everything Dawn will do until the mission is over in 2016, after leaving Ceres.

Though thought-provoking as it seems, Dawn, has almost completed its mission: to travel to two protoplanets, 4 Vesta and 1 Ceres. “Dawn, as a mission belonging to NASA’s Discovery Program, delves into the unknown, drives new technology innovations, and achieves what's never been attempted before,” accurately describes Dawn’s mission, unbiased on how the universe was created. The Dawn mission, though, hopefully will be a successful one. We actually now have evidence that it should be—the pictures of 4 Vesta taken from Dawn. These pictures will help fine-tune navigation during its approach; July 16 (2011) is the proposed day for achieving orbit when the asteroid itself is 117 million miles away from the green planet.

Dawn will be ahead of schedule if it reaches Vesta on July 16. Launched from earth on September 27, 2007, it’s traveled for quite some time to get where it wants to go. It actually was supposed to launch on April 10^, 2007, but a myriad of delays kept it back. Now, when Dawn is so close to Vesta, NASA hopes nothing to misshapen. As time traveled on, Dawn flew by Mars in February 2009 for gravitational assistance and will arrive, orbiting Vesta quite soon, much earlier than the proposed October 2011. From then on, Dawn will depart Vesta in May 2011 and visit Ceres in August 2015. It ends its mission on January 16 2016.

Named after a Roman virgin goddess or hearth and home, 4 Vesta is a protoplanet remnant. Being the second-most massive 'minor-planet' in the solar system, it was easily detected by German astronomer Heinrich Wilhelm Olbers on March 29, 1807. Its orbit is depicted below, and extends beyond Mars, but much closer than Jupiter. [The orbit image was taken on May 11, 2011. Its position will change by tomorrow, or whenever this is viewed.]

The Pictures taken by Dawn are incredible. Taken on May 3 (2011) when Dawn began its approach of Vesta (725,000 thousand miles from Vesta), “The asteroid appears as a small, bright pearl against a background of stars,” JPL writes. Although a colloquial expression, Vesta is far from being a pearl with a diameter of (approximately—Dawn will find out) 330 miles wide. Space-bound telescope have gotten just a fuzzy orb, so these pictures by Dawn are a step up. Dawn will also take closer pictures to reveal surface detail, like New Horizons will when it reaches Pluto in 2015. Pluto (a Kuiper Belt Object) has a fuzzy image as seen from ground telescopes; New Horizons will hopefully fix that.

So, mark your calendars as you save this important date: July 16 2011. Dawn will enter Vesta’s orbit and the fun will begin!

  

Where is Dawn Now? http://neo.jpl.nasa.gov/orbits/fulltraj.jpg

And now for the pictures: 1) This image shows the first, unprocessed image obtained by NASA's Dawn spacecraft of the giant asteroid Vesta in front of a background of stars. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA 2) This image, processed to show the true size of the giant asteroid Vesta, shows Vesta in front of a spectacular background of stars. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.