It’s been a big year for Mars. The InSight lander is on the way to the Red Planet, scheduled to land November 26 on a mission to take the vital signs of Mars. There’s a big dust storm on Mars just as it reaches opposition this week, its closest approach to Earth since 2003. Oh, and organics have been found on Mars.
We may have buried the lede on that one.
July 18 image of Mars by the Hubble Space Telescope.
(Image credit NASA, ESA, and STScI)
The discovery of organics on Mars is evidence that science is not necessarily fast. The work came out of a hole the Curiosity rover drilled in a Mars rock way back in 2015. The papers outlining the discovery just came out earlier this year.
“What it found in a rock that is about three-and-a-half billion years old was organic molecules,” Cuomo said. The substance found was kerogen, which Cuomo called, “a gooey precursor to petroleum.”
Cuomo repeatedly stressed that this does not, not, not mean that there is or ever was life on Mars.
“What we have found is evidence that the building blocks for life on Mars certainly did exist three-and-a-half billion years ago,” he said. “This was the first time that we found clear evidence that this was there.”
Cuomo noted that we know a good bit about the history of the surface of Mars.
“Mars certainly was a warmer and a wetter environment that could have supported life, that life could have evolved on,” he said. “What we don’t know—and this is what InSight is going to help us find out—is how long Mars was more Earth-like.” The longer that warm, wet environment lasted, the greater the potential that life could have arisen.
InSight
Krumm noted that InSight is something of an interplanetary RN.
“It’s going to be taking Mars’ vital signs,” he said. It will use a seismometer to take Mars’s pulse, a heat flow probe to measure its temperature, and the Rotation and Interior Structure Experiment, RISE, will check its reflexes, precisely tracking the location of the lander to determine just how much Mars’ north pole wobbles as it orbits the Sun. Cuomo said a big part of the mission’s purpose is to find out if Mars has a molten core today.
“It has volcanoes, so we know at some point in the past it had a molten interior,” he said. “It had a magnetosphere—the remnants of it are frozen in the rocks—but it does not have an active magnetosphere.”
InSight will help us figure out of the core solidified, or if there’s some other reason for the loss of the magnetosphere. Krumm and Cuomo showed this video about the InSight mission.
The Pacific Science Center plans an event for watching the InSight landing on November 26. Watch this space for details!
Dust storm
The rover Opportunity is powered by solar panels, and the dust storm on Mars has blocked the Sun to an extent that Opportunity has shut down. NASA hasn’t heard from Opportunity since June 10. It’s programmed to switch back on every so often, and shut right back down if it doesn’t find power. Cuomo said that can only go on for so long.
“It’s possible it won’t wake up,” he said. If that happened, it would be a sad end to a tremendous run. Opportunity and its twin, Spirit, landed on Mars in 2004 on missions expected to last 90 days. The last contact with Spirit, stuck in the sand, was in March 2010, while Opportunity, up until last month, at least, has been running for more than 14 years.
Opposition
Mars reached opposition to Earth on the evening of July 26 in Pacific Daylight Time, and will be at its closest approach to Earth for the year on Tuesday, July 31. Those dates are different because of the geometry of the elliptical orbits of the two planets. In any case, we’re closer to Mars than at any time since the great apparition of 2003, which is good news for amateur astronomers. The bad news is that the dust storm could foil our attempts to image and observe surface features of Mars. There was word this week, however, that the storm is fading. Bright red Mars will be a good observing target for the rest of the summer and into early fall.
David Trilling of Northern Arizona University noted that the LSST will have an 8.4-meter mirror and a camera the size of a small car.
“In terms of telescopes, this is a really, really, really big machine,” he understated. That car-sized camera will boast 3.2 billion pixels.
“You’d need 1,500 HDTV screens to look at a single LSST image,” Trilling said. LSST will scan the entire night sky every three to four nights for ten years.
“That’s about ten terabytes of data every night, which is a huge computational challenge,” he noted.
It’s an asteroid. It’s a comet. It’s complicated…
Michael Mommert of Lowell Observatory studies asteroids and comets. He said that sometimes it’s difficult to tell one from another. An asteroid can look like a comet if the asteroid is “active.” This could be because it collided with something else, or it is spinning rapidly, or it was warmed by its proximity to the Sun.
“If we can understand those active asteroids we can better understand the average asteroid,” Mommert said. “We can learn a lot about the mechanisms that are going on in asteroids from those active asteroids.”
Similarly comets can go dormant, with no tail, and look more like asteroids. As they often share similar properties, Mommert said comets and asteroids are on something of a continuum rather than being two distinct types of objects.
In his research Mommert is tracking about 20 active asteroids and 50 dormant comets. He figures he spends 30 nights per year using a telescope. He’ll be able to cut down that time tremendously with LSST; he’ll be able to find his targets and pull data collected by the telescope.
“LSST will improve our understanding of small body populations,” Mommert said. “Asteroids, comets, active asteroids, everything that is out there.”
Tales from the Outer Solar System
Kat Volk of the University of Arizona focuses her research on objects in the outer solar system. Pluto, Eris, and other far-out objects have been discovered by comparing photos of an area of sky and looking for something that moved. In fact, Pluto was the first object discovered in this way.
There are about 2,000 known objects in the Kuiper Belt. That’s about how many asteroids we knew of a century ago.
“Kuiper Belt science is a hundred years behind Asteroid Belt science because these things are just so much more difficult to find,” Volk said, because they’re far away, faint, and move slowly. “We had to wait until we had digital cameras and computers to process those images.”
Volk said we probably have discovered all of the 10-kilometer asteroids and most of the 1-kilometer ones. They’re easier to spot because they’re brighter, and there’s money for the hunt because of the potential threat asteroids pose to Earth.
“For comparison, the smallest ever observed Kuiper Belt object is 30 kilometers across, very roughly,” Volk said, adding that we only found that one because the Hubble Space Telescope was used to look for another target for the New Horizons mission after it passed Pluto.
“We’re pretty incomplete in terms of our object inventory in the outer solar system,” Volk said. She said LSST will change that.
“They expect 40,000 new Kuiper Belt ojects,” Volk said. “It’s going to be an entirely new era for the Kuiper Belt with a huge playground of new objects to look at.”
“I am realy excited to see what we’re going to find with LSST, and it’s going to completely revamp our idea of the outer solar system.”
A Crash Course in Asteroid Defense
Andy Rivkin of the Johns Hopkins University Applied Physics Laboratory said that even a 20-meter asteroid packs a wallop when it smashes into Earth. That was roughly the size of the Chelyabinsk meteor in 2013.
Doing the math tells us that there should be about 10 million objects of that size zipping around the solar system, but so far we’ve found only around 10 thousand of them. Back in 2005 Congress told NASA to find 90 percent of objects 140 meters or larger.
“LSST is going to be a critical piece in reaching this goal,” Rivkin said, “and we expect that by 2034 about 86 percent of hazardous asteroids will be found.”
So, what do we do when we spot one headed our way? Rivkin said that for really small ones, like Chelyabinsk, and really large ones, the best idea might be duck and cover. There’s not much to be done about something very large, and small ones don’t pose much of a threat. For those in between, a few options are viable. For one, we could try to deflect the asteroid with a nuclear bomb.
“A lot of people are uncomfortable with nuclear explosions in space, for good reason, and so there’s been a lot of interest in having something else that could work,” Rivkin said.
That something else is a kinetic impactor, which is a fancy way of saying we’ll just smash something into the asteroid to change its speed, and therefore its orbit. It’s a fine idea in theory, but we have no idea if it would actually work. Rivkin is involved in a project that will give it a try.
It’s called DART, which is for Double Asteroid Redirection Test. DART is on schedule to launch for the asteroid Didymos in June of 2021, and then crash into its satellite, nicknamed “Didymoon,” in October 2022. Astronomers will watch through ground-based telescopes and see what happens. Rivkin called it a dress rehearsal for the day we might have to do something about an incoming asteroid.
“A dress rehearsal for, needless to say, a performance we hope never to actually stage,” he said, “demonstrating that we could do this, allowing us to pin these computer simulations to something real, allowing us to better understand asteroidal properties, and giving us a lot of science as an ancillary benefit.”
Astronomy on Tap Seattle is organized by graduate students in astronomy at the University of Washington.
The weather gets to amateur astronomers from Seattle sometimes. I had several conversations at the Seattle Astronomical Society’s annual banquet back in January with attendees who, like me, fessed up to not doing much observing these days. It’s so cloudy so often that we tend to forget about the telescope, waiting patiently in the corner down by the door to the wine cellar. So it was fun on a string of clear evenings recently to get out and get some scope time.
I even announced it on Twitter.
Hey, that bright thing near the Moon is Jupiter! Look up! Clear sky in Seattle!! pic.twitter.com/ZfEByjy9t1
The views of Jupiter on that night were a little murky, though the Great Red Spot occasionally popped into sight as plain as the cyclone on your face. The next evening seeing and transparency were about as good as they get in West Seattle, and I enjoyed some of the best views of Jupiter I’ve ever had.
I also took a look at Saturn, which was at opposition June 27, but on that evening it was still awfully low in the southeast sky and thus looked pretty fuzzy. I’m looking forward to some better views of Saturn as it comes around a little earlier in the evening each day. I took a few peeks at Venus, too.
While Jupiter and Saturn are among my favorite observing targets, the big show of the summer will be put on by Mars. The Red Planet will reach opposition on July 30, and this particular apparition will be an outstanding one. Mars will be the closest it has been to Earth since 2003, which was its closest approach in 60,000 years! It was that event that pushed me to get more involved in observational astronomy. This summer we’ll have great opportunities to see surface details on Mars.
As I write this, at 1 p.m., it’s looking pretty clear outside, though some clouds are in the forecast for the early morning hours. I shouldn’t even think this, lest to jinx clear skies, but I think I’ll get out again today and see how Saturn is looking.
