Billions of years ago, a version of our Earth that looks very different than the one we live on today was hit by an object about the size of Mars, called Theia – and out of that collision the Moon was formed. How exactly that formation occurred is a scientific puzzle researchers have studied for decades, without a conclusive answer.
Most theories claim the Moon formed out of the debris of this collision, coalescing in orbit over months or years. A new simulation puts forth a different theory – the Moon may have formed immediately, in a matter of hours, when material from the Earth and Theia was launched directly into orbit after the impact.
Eclipses recur over the Saros cycle, a period of approximately 18 years 11 days.
The saros is a period of exactly 223 synodic months, approximately 6585.3211 days, or 18 years, 10, 11, or 12 days (depending on the number of leap years), and 8 hours, that can be used to predict eclipses of the Sun and Moon.
One report describes the crew as “infuriated” that Mission Control seemed unconcerned. When Commander Gibson saw the damage he thought to himself, “We are going to die”, and did not believe that the shuttle would survive reentry; if instruments indicated that the shuttle was disintegrating, he planned to “tell mission control what I thought of their analysis” in the remaining seconds before his death.
The shuttle Atlantis actually sustained more damage than what would bring down Columbia in 2003. The Top Secret payload (a surveillance satellite for the US DOD) meant that communication with the ground was done using a slower method of encryption which could have resulted in lower quality images for analysis (eg. higher compression for faster transmission over a slow line).
One of the most fundamental questions in astronomy is that of just how many galaxies the universe contains. The landmark Hubble Deep Field, taken in the mid-1990s, gave the first real insight into the universe’s galaxy population. Subsequent sensitive observations such as Hubble’s Ultra Deep Field revealed a myriad of faint galaxies. This led to an estimate that the observable universe contained about 200 billion galaxies.
The new research shows that this estimate is at least 10 times too low.
NASA’s Juno spacecraft captured a unique time-lapse movie of the Galilean satellites in motion about Jupiter. The movie begins on June 12th with Juno 10 million miles from Jupiter, and ends on June 29th, 3 million miles distant. The innermost moon is volcanic Io; next in line is the ice-crusted ocean world Europa, followed by massive Ganymede, and finally, heavily cratered Callisto. Galileo observed these moons to change position with respect to Jupiter over the course of a few nights. From this observation he realized that the moons were orbiting mighty Jupiter, a truth that forever changed humanity’s understanding of our place in the cosmos. Earth was not the center of the Universe. For the first time in history, we look upon these moons as they orbit Jupiter and share in Galileo’s revelation. This is the motion of nature’s harmony.
The brilliant flash of an exploding star’s shockwave—what astronomers call the “shock breakout” — is illustrated in this cartoon animation. The animation begins with a view of a red supergiant star that is 500 times bigger and 20,000 brighter than our sun. When the star’s internal furnace can no longer sustain nuclear fusion its core to collapses under gravity. A shockwave from the implosion rushes upward through the star’s
One of the most tragic events in the history of space exploration is the loss of the space shuttle Columbia and all seven of its crew on February 1, 2003—a tragedy made worse because it didn’t have to happen. But just as it is human nature to look to the future and wonder what might be, so too is it in our nature to look at the past and wonder, “what if?” Today, 13 years after the event, Ars is rerunning our detailed 2014 examination of the biggest Columbia “what if” of all—what if NASA had recognized the danger? Could NASA have done something to save the crew?