While analyzing NASA Hubble Space Telescope images of the Sagittarius dwarf irregular galaxy (SagDIG), an international team of astronomers were surprised to see the trail of a faint asteroid that had drifted across the field of view during the exposures. The trail is seen as a series of 13 reddish arcs on the right in this August 2003 Advanced Camera for Surveys image. As the Hubble telescope orbits around the Earth, and the Earth moves around the Sun, a nearby asteroid in our solar system will appear to move with respect to the vastly more distant background stars, due to an effect called parallax. It is somewhat similar to the effect you see from a moving car, in which trees by the side of the road appear to be moving much more rapidly than background objects at much larger distances. This is a previously unknown asteroid, located 169 million miles from Earth at the time of observation. The distance places the new object, most likely, in the main asteroid belt, lying between the orbits of Mars and Jupiter. Based on the observed brightness of the asteroid, the astronomers estimate that it has a diameter of about 1.5 miles. The brightest stars in the picture (easily distinguished by the spikes radiating from their images, produced by optical effects within the telescope), are foreground stars lying within our own Milky Way galaxy. Their distances from Earth are typically a few thousand light-years. The faint, bluish SagDIG stars lie at about 3.5 million light-years (1.1 Megaparsecs) from us. Lastly, background galaxies (reddish/brown extended objects with spiral arms and halos) are located even further beyond SagDIG at several tens of millions parsecs away. There is thus a vast range of distances among the objects visible in this photo, ranging from about 169 million miles for the asteroid, up to many quadrillions of miles for the faint, small galaxies.
The new and unfinished BER Willy Brandt Berlin Brandenburg International Airport, including the control tower, stand on July 3, 2015 in Schoenefeld, Germany. Authorities have announced that the new airport, which stands adjacent to Schoenefeld Airport and is to become the German capital's main airport, will open for operation in the fall of 2017, five years behind schedule. The new airport has been plaqued by corruption, delays and cost-overruns and its opening has been postponed repeatedly.
Credit: Sean Gallup
A passenger jet of airline easyJet taxis past the new and unfinished BER Willy Brandt Berlin Brandenburg International Airport on July 3, 2015 in Schoenefeld, Germany. Authorities have announced that the new airport, which stands adjacent to Schoenefeld Airport and is to become the German capital's main airport, will open for operation in the fall of 2017, five years behind schedule. The new airport has been plaqued by corruption, delays and cost-overruns and its opening has been postponed repeatedly.
Credit: Sean Gallup
An RAF C-17 aircraft comes in to land carrying the bodies of eight British nationals killed in last Friday's terrorist attack in the Tunisia beach resort of Sousse on July 3, 2015 in Brize Norton, England. British nationals Christopher and Sharon Bell, Scott Chalkley, Sue Davey, Angie and Ray Fisher, Eileen Swannack and John Welch are eight of the 30 Britons killed in last week's terror attack who have been repatriated today.
Credit: WPA Pool
New Jersey Governor and Republican presidential candidate Chris Christie greets people at Mary Ann's Diner July 3, 2015 in Derry, New Hampshire. Christie announced his candidacy on June 30 and is spending five days in the first in the nation primary state over the fourth of July holiday weekend.
Credit: Darren McCollester
Revd Canon Alison Mary White poses for a photograph after being Consecrated As Bishop of Hull at York Minster on July 3, 2015 in York, England. The Church of England has appointed its second female bishop during a ceremony at York Minster today, after it adopted legislation last November to allow women bishops. The Reverend Alison Mary White was consecrated as the new Bishop of Hull, following The Reverend Libby Lane, who was appointed as Bishop of Stockport in January.
Credit: Nigel Roddis
King Felipe VI of Spain (L) receives Madrid Mayor Manuela Carmena (R) at the Zarzuela Palace on July 3, 2015 in Madrid, Spain.