This Week in Space: Supernova Reruns, Baby Planets, and Mars Weather
As a kid, I always found it disappointing to turn on my favorite TV show only to discover it was an episode I’d already seen. Nobody likes reruns. Except for astronomers using the Hubble Space Telescope. They’re waiting for the biggest repeat performance in the universe: a supernova.
In November 2014, scientists spotted supernova heic1505, not just once but four times, spread out across the sky. This is actually an effect of relativity. Basically, the enormous gravity of a galaxy cluster that sits between us and the supernova bends the light from the supernova, a bit like light bending through a camera lens — in fact, the effect is called “gravitational lensing.”
The supernova’s light is bent around that galaxy in a few different directions, so we see what looks like four different supernovas in slightly different parts of the sky. It’s an optical illusion at a cosmic scale.
What makes astronomers excited about heic1505 is that gravitational lenses can often bend light into taking much longer paths before it reaches us. Since the speed of light is fixed, the farther the light has to travel, the longer it takes. It’s like the universe’s own DVR. And that’s why Hubble scientists are now monitoring the general vicinity of heic1505, hoping they’ll get a chance to time-shift the initial explosion of the supernova and watch it as it explodes.
Unfortunately, it isn’t as easy as pressing the Play button on your remote. Scientists have to calculate the mass of the galaxy cluster in order to estimate when we might see another afterimage of the supernova. But when this repeat performance does arrive, it’ll actually be welcome.
Birth of a planet
Our solar system is middle-aged, fully formed, with all its planets firmly held in place. So to learn about how solar systems form, we have to look outward, scanning the galaxy for systems just being born. For the first time, astronomers at the University of Arizona and Stanford University have found a planet that’s still in the process of forming.
There’s a planet in there somewhere, apparently. (Photo: NASA.gov)
The planet, which appears to be growing into a Jupiter-size gas giant, is orbiting a star 450 light years away. Just-forming solar systems are a mess, with debris everywhere in what’s called a “transition disk.” As planets form, their gravitational pull sweeps up gas and dust as it starts to clear the area between the outer disk of debris and the sun.
Having spotted conditions at the star that looked good for planetary formation, the astronomers used telescopes to search for wavelengths of light that contained the signature of gas heating up as it’s sucked up by a voraciously growing giant. And their observations confirmed the results: a baby planet, a couple of million years old and ready to be fed.
Mars weather report
It’s easy to think of other planets as abstract concepts, dots of light in the sky, or pretty orbs you can use as wallpaper on your computer. It’s a bit harder to think of them as actual places, as terrain we might find on Earth. It’s mostly a matter of perspective: So many space images are taken from orbiters rather than down on the surface, where most of us humans spend our time.
While we’ve landed on quite a few interesting worlds, the planet that we’ve spent the most time on lately is Mars. And with seven different missions currently operational on and around Mars, including two active rovers, Mars keeps becoming more of a real place and less of a concept. It’s got hills, and gullies, and sand dunes, and our rovers keep on rolling and snapping pictures along the way.
Where’s Matt Damon? (Photo: NASA.gov)
The Curiosity rover is rolling toward some sand dunes right now, and the color-corrected pictures it’s taking wouldn’t look out of place in the Mojave Desert.
Mars has weather too. Among our many currently active Mars satellites is the Mars Reconnaissance Orbiter, which — among other tasks — serves as a weather satellite for the planet. And the manufacturer of one of the instruments on the spacecraft, the Mars Color Imager, has taken on the task of being the first Mars weather reporter.
So thanks to Malin Space Science Systems, I can bring you this weather report: Scattered water-ice clouds across equatorial regions. In the western hemisphere, there was a large dust storm over the northern plains. Skies over the Mariner Valleys were clear.
Now let’s turn to the traffic report: Mars’s two vehicles, Opportunity and Curiosity, experienced storm-free skies and no chance of any traffic jams. Because while Mars is most definitely a place, it’s also a very empty one.
