Most asteroids carry a name nobody remembers. Apophis is the exception: it sounds like a movie villain, and its first weeks in the headlines read like a thriller. The real story is a mix of a routine survey night, a lost object, a holiday-season scare and a naming choice that turned out to fit better than anyone planned.
Apophis was discovered on June 19, 2004, by astronomers Roy Tucker, David Tholen and Fabrizio Bernardi, working at the Kitt Peak observatory in Arizona. It was a faint, fast-moving dot, and it was observed over just two nights before it slipped away. It received the temporary designation 2004 MN4, which simply encodes the discovery period (the second half of June 2004) and the order in which it was logged.
For a few months nobody paid attention. Two nights of data are not enough to pin down an orbit, and the object faded out of view as it moved along its path. In the meantime, it was one of thousands of new near-Earth objects waiting for a second look.
On December 18, 2004, Gordon Garradd of the Siding Spring Survey in Australia picked the object up again. Now there were two sets of observations about six months apart, and automatic impact-monitoring systems could finally calculate where it would go. The results were alarming. Within days the object was rated level 2 on the Torino Scale, and by December 24 it reached level 4, the highest value any asteroid has received. On December 27, NASA's Jet Propulsion Laboratory calculated roughly a 1-in-37 chance of an impact on April 13, 2029.
That figure sounds dramatic, but it reflected a poorly known orbit, not a real trajectory heading for us. Our article on how NASA tracks asteroids explains why early risk numbers behave this way: they are the share of a wide cloud of possible orbits that touch Earth, and the cloud shrinks as data arrives.
The same day the 1-in-37 figure appeared, astronomers searched old survey images for a faint trace of 2004 MN4. They found it in images from March 15, 2004, months before the official discovery. Those pre-discovery observations stretched the observing arc from roughly 190 days to about 288, and the impact probability for 2029 fell below 1 in 10,000. Additional optical and radar measurements in early 2005 removed the 2029 impact entirely. The full story of how the risk was cleared is in Is Apophis Dangerous?
A smaller risk from later encounters kept the Torino rating at 1 for a while, until more data closed those possibilities too.
Once an orbit is well determined, the Minor Planet Center assigns a permanent number. 2004 MN4 became (99942) in June 2005. A numbered asteroid can be named, and the right to propose the name belongs to its discoverers. Tucker and Tholen proposed Apophis, and the name was accepted by the International Astronomical Union later in 2005, according to the commonly cited timeline.
Apophis is the Greek form of Apep, an enormous serpent in ancient Egyptian religion. Each night the sun god Ra was said to travel through the underworld in his boat, and Apep tried to stop him and plunge the world into darkness. Myths describe the serpent as the embodiment of chaos, the opposite of order. A name linked to the destruction of the world is a natural joke for an asteroid that had just frightened the planet.
There is also a pop-culture connection. Apophis is the name of a recurring villain in the TV series Stargate SG-1, and Tucker and Tholen have been reported as fans of the show. The show link comes from secondary reporting rather than an official statement, so treat it as a likely influence, not the sole reason.
Asteroid families have naming traditions. Aten-type asteroids, whose orbits mostly stay inside Earth's, are traditionally given Egyptian names, while Apollo-type asteroids get names from Greek mythology. Apophis is the Greek spelling of an Egyptian name, which happens to match its destiny. During the April 2029 flyby, Earth's gravity will enlarge its orbit and reclassify it from an Aten to an Apollo asteroid. The details of that change are in our complete Apophis guide.
The episode is also a reminder of why surveys and quick response matter, a theme explored in our planetary defense overview.
Is Apophis named after the Stargate villain? The villain and the asteroid share a mythological source. The show seems to have inspired the choice, but the Egyptian myth and the Aten-Apollo naming tradition are the official logic.
What does 2004 MN4 mean? The year, a letter for the half-month of discovery, and a second letter and number for the order of discovery within that period.
Who owns the right to name an asteroid? The discoverers propose it, and the IAU approves it.
Facts in this article are drawn from public scientific sources. For primary information, see: