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?
With such rapid expansion of capability, it may seem difficult to tell what the next 60 years will bring, much less the next century. But we never do anything in space without first imagining what we could do, so in that spirit, here is an attempt to predict—and nudge us into—the future.
That left some speculation about, um, aliens. While it’s incredibly unlikely, it does kinda fit what we’re seeing. An advanced civilization would have big energy requirements, and it would make sense to build huge structures around their star to capture as much light as possible for solar power. The dips in light we see are then these “megastructures” passing in front of the star (some people call this a Dyson Swarm; a collection of enormous solar panels enclosing the star).
An Amateur Radio Astronomer in North Cornwall accidentally picked up the signal in 2013 and after cross checking with various lists, has identified it as LES1 built by the Massachusetts Institute of Technology and launched in 1965. The satellite failed to reach its intended orbit owing to a wiring error and has been drifting out of control ever since.