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Hubble image of the Arp 147 galaxies, taken October 27

Hubble image of Arp 147, taken October 27  Courtesy NASA, ESA, and M. Livio (STSci).

October 31, 2008: Hubble Telescope Resumes Operation.
The Hubble Space Telescope returned to normal operation on October 27.  The service mission to replace the faulty electronics and add new instruments is expected to launch in May  (continue)
October 20, 2008: IBEX Successfully Launched.
The IBEX satellite was successfully placed into space on October 19.  (continue)
Photograph of the supernova remnant CTA 1.

An image of the supernova remnant CTA 1, which contains a gamma-ray pulsar.  Courtesy NASA/S. Pineault, DRAO.

October 17, 2008: Pure Gamma-Ray Pulsar Found.
A spin-powered pulsar that is visible only at gamma-ray energies has been found by the Fermi Gamma-Ray Space Telescope in a distant supernova remnant.  (continue)
October 15, 2008: IBEX Set for a Sunday Launch.
The Interplanetary Boundary Explorer is set to launch on October 19. This Earth-orbiting spacecraft will map the boundary between the solar wind and the interstellar gas.  (continue)
September 30, 2008: Hubble Failure Delays Refurbishment.
An electronic component on the Hubble Space Telescope failed on September 27, 2008, causing a delay until the beginning of 2009 in the Space Shuttle mission to refurbish the telescope. The telescope is expected to return to operation after it is reconfigured to use a backup system.  (continue)
September 13, 2006: Largest Dwarf Planet Given Name Eris.
The largest dwarf planet in our Solar System is now formally named Eris, after the Greek god of strife. The name is fitting, given that the discovery of Eris led to the demotion of Pluto to dwarf planet status. The moon of the Eris was given the name Dysnomic.  (continue)
August 24, 2006: Pluto Falls from the List of Planets.
The International Astronomical Union approved a definition for ?planet.? Whether an object is a planet is set by its physical characteristics. First, the object must be in orbit around the Sun, but not around another body. Second, it must be large enough to be round through its self-gravity. Finally, and this criterion is key, it must have cleared the neighborhood of its orbit of other objects. This last criterion eliminates Pluto as a planet. Pluto is now a dwarf planet, and the prototype of the class of plutonian objects.  (continue)
August 3, 2005: A New Planet?
A Kuiper Belt object with a radius comparable to Pluto's has been found. This object is far outside of the orbit of Neptune, with a semimajor axis of 67.5 AU and an orbital period of 560 years. Now the question arises: do we consider this object a planet or a planetoid?  (continue)
May 11, 2005: NASA's Swift Locates a Short Gamma-Ray Burst.
The Swift gamma-ray observatory, a NASA satellite that was launched last fall, has produced the first accurate location for a short gamma-ray burst. Previous to this observation, only long gamma-ray bursts had been located. The short bursts behave differently than the long bursts, and they are widely believed to be produced by a different object (long bursts are produced in the supernovae of massive stars). An elliptical galaxy falls on the burst location, but no source for the burst is visible.  (continue)
January 21, 2005: First Scientific Results from the Huygens Landing on Titan.
The Huygens science team has released the first results from the January 14, 2005 landing of the Huygens probe onto Titan. The team stated that the Titan terrain bears the marks of the precipitation and flow of liquid methane. The surface of Titan was found to be a loose soil of water-ice particles mixed with water-ice pebbles.  (continue)
January 14, 2005: Huygens Probe Lands on Titan.
The Huygens probe successfully landed on the surface of Titan, sending back pictures of the moon's surface for 90 minutes before losing contact with its parent craft, the Cassini spacecraft.  (continue)
January 12, 2005: Huygens Probe to Land on Titan.
Huygens Probe to land on Titan this week. The Huygens probe, which was released from the Cassini spacecraft, is set to land on Titan, Saturn's largest moon, on the morning of January 14  (continue)
November 20, 2004: Swift.
NASA successfully launched the Swift satellite into orbit on November 22 at 12:16pm EST (17:16 GMT). Swift is now in its activation phase, which will last 45 days.  (continue)
November 17, 2004: NASA to Launch the Swift satellite.
The Swift satellite is set to launch on November 17, 2004 from Cape Canaveral. This satellite is designed specifically to detect and localize gamma-ray bursts.  (continue)
October 28, 2004: Cassini Flies by Titan.
The Cassini spacecraft flew by Titan, Saturn's largest moon, at 15:30 UTC on October 26 Cassini came within 1,174 km of Titan's surface, and during this time observed Titan with eleven of its twelve instruments. This is the closest flyby of Titan by any spacecraft.  (continue)
October 27, 2004: Star Associated with Tycho Supernova Found.
Researchers announced the discovery of a companion star to the presumed white dwarf that produced the Tycho remnant. The discovery supports the theory that type 1a supernovae are produced by the thermonuclear explosion of a white dwarf pushed over the Chandrasekhar mass limit through accretion of material from a companion star.  (continue)
September 27, 2004: How Mars Loses Water.
A mechanism for water removal from Mars has been verified. The surface of Mars has features that show water once flowed freely on the planet. Now, however, the amount of of water on Mars is small. Observations by an instrument on the ESA Mars Express satellite that is designed to measure the penetration of the solar wind into the Martian atmosphere has found that the solar winds penetrates deeply enough to account for Mars's loss of water.  (continue)
September 13, 2004: Mass of a Neutron Star Determined.
Two astrophysicists, Tod Strohmayer of the NASA Goddard Space Flight Center and Adam Villarreal of the University of Arizona, have determined the radius and mass of the neutron star in the x-ray binary system EXO 0748-676. This binary system is a low-mass x-ray binary that is a transient x-ray burst source. The system consists of a neutron star and a small main-sequence star in close orbit. Observing a characteristic frequency of 47 Hertz in the variability of the x-ray light curve with the NASA Rossi X-Ray Explorer, and using earlier x-ray line observations from the ESA XMM-Newton satellite, they derived a radius in the range of 9.5 and 15 km, with a best estimate of 11.5 km, and they derive a mass of 1.5 and 2.3 solar masses, with a best value of 1.75 solar masses. They presented their results on September 8 at the AAS HEAD meeting in New Orleans.  (continue)
August 5, 2004: New Observations by Cassini.
Researchers for the Cassini mission to Saturn today announced three new observations: the detection of lightning in Saturn's atmosphere that is different in character than was previously observed, the discovery of an additional radiation belt above Saturn's cloud tops, and the observation of a fluorescent glow in the upper atmosphere of Titan.  (continue)
Photograph of the launch of the Messenger spacecraft.

A Delta 2 rocket successfully launches the Messenger spacecraft into space at 6:15:56 GMT from the Cape Canaveral Air Force Station, Florida, USA. Photo credit: Courtesy NASA.

August 3, 2004: NASA Launches the Messenger Spacecraft to Mercury.
At 6:15 GMT (2:15 EDT) this morning the Messenger spacecraft was launched on its way to Mercury, the least studied by spacecraft of the four terrestrial planets. Messenger will fly by Mercury three times, with the first flyby occurring in January of 2008, before it enters an orbit around Mercury in March of 2011. The spacecraft will map the planet and characterize the planet's structure, composition, and geological history. Along the way the spacecraft's investigators hope to solve several puzzles about the planets composition and magnetic field.  (continue)
July 22, 2004: Chandra Observes Flaring Star in Nebula.
The Chandra X-Ray telescope observes a flare from the star in McNeil's nebula. The nebula is illuminated by a very young star that undergoes periods of brightening. The current theory is that a disk of material orbiting the star is accreting onto the star, and that occasionally, because of the generation and expulsion of magnetic fields within the disk, the accretion rate dramatically increases. The higher accretion rate leads to a brightening at optical wavelengths, while the expulsion of the magnetic field leads to a brightening in the x-ray. Amateur astronomer Jeff McNeil discovered the eponymous nebula with a 3-inch telescope in January of 2004.  (continue)
Photograph of Saturn's ring.

Saturn's ring in its natural colors as seen by the Cassini probe. Photo credit: Courtesy NASA/JPL-Caltech.

July 21, 2004: Cassini Photographs Saturn's Ring.
A photograph from the Cassini probe of Saturn's ring is released. The image is a composite from Cassini's narrow-angle camera taken of the ring. The image shows the rings' natural colors in the visible wavelengths. The particles that constitute the ring are predominately ice. The range of browns seen in the ring are thought to be a consequence of contamination of the ring by silicates and carbon.  (continue)
July 20, 2004: Thirty-fifth Anniversary of First Walk on Moon.
On this day 35 years ago Neil Armstrong and Buzz Aldrin took their first steps on the surface of the moon, achieving the first part of president John F. Kennedy's challenge to NASA of landing a man on the moon and bringing him safely home before the end of that decade.  (continue)

Issue 5.18, October 31, 2008.

2008 The Astrophysics Spectator.

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