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Comet Leonard Suddenly Brightens. Has It Broken Up? Is it gone for ever?
Taken by Ray Pickard on December 20, 2021 @ Bathurst Observatory, NSW Australia
Comet Leonard (C/2021 A1) is bright again. On Dec. 20th, astronomers witnessed an outburst from the comet's core. In a matter of hours, it multiplied in brightness almost 10-fold. "Tonight it was clearly visible as a 'star' to the left of Venus," reports Jan Hattenbach, who sends this picture from La Palma in the Canary Islands: "I estimate magnitude 3 or brighter," he says.
The outburst might signal a fragmentation event in the comet's core. This would come as no surprise. The comet is heading for its closest approach to the sun (0.61 AU) on Jan. 3rd. Increasing heat may be liberating new jets of gas and dust from the comet's core--or worse, blowing away huge chunks of ice and rock.
Astronomers in the southern hemisphere have the best view. "The comet is now nicely placed for us in Australia," says Ray Pickard at the Bathurst Observatory in New South Wales. Here is what he saw through the observatory's telescope:
"The comet seems to be having an outburst with a noticeable jet of material [emerging from the core]," he says. Amateur astronomers are encouraged to monitor Comet Leonard while the outburst continues. If it's a big breakup, the comet might disintegrate and fizzle. Otherwise, it could brighten even more as the comet approaches the sun.
By Christmas night it should be lined up to the left of Jupiter. Comet Leonard on the evening of December 25 in relation to Venus, Saturn and Jupiter.
Chinese Rover Spots A "Moon Cube," And Opens A New Lunar Mystery
The Moon Cube, "Mystery Hut," or "Mystery House" on the dark side of the Moon
Our SpaceThe "Face on Mars" illusion dispelled by the Mars Reconnaissance Orbiter imaging the same mesa in Cydonia from a different angle. NASA
An image has tantalized the internet: an enigmatic cube-shaped object on the far side of the moon. China's robotic Yutu-2 lunar rover spotted a remarkably square-looking gray object on the horizon on its 36th lunar day, according to reporting by Space.com, which translated an entry in a rover mission diary from the Chinese language website Our Space.
Taken from around 260 feet away, the "mystery hut," or "mystery house," as Our Space put it, appears like a tiny cube the same color as the lunar regolith, but with a black rectangle in the center. Almost like a door ... or a Kubrick-esque monolith.
The Moon Cube, "Mystery Hut," or "Mystery House" on the dark side of the Moon Our Space
Zoom on the picture, and it becomes significantly blurry, but the overall impression of something with disconcertingly square proportions remains.
A close-up view of the Moon Cube, "Mystery House," or "Mystery Hut"The Moon Cube, "Mystery Hut," or "Mystery House" on the dark side of the Moon Our Space
But while human craftsmanship tends to result in square angles and straight lines, not all square angles and straight lines result from human, or alien, handiwork. Byrne guides Inverse through a few scenarios:
- It could be an illusion: "Why might it appear square or cubic? First, the image looks to have a pretty low resolution of features at or beyond the horizon, so it might not actually be square," Byrne says.
- It might have just been forged that way by natural causes: Even if it is square, "lots of boulders are blocky, squarish, or cubic/cuboidal because rocks commonly develop fracture sets that result in blocks," Byrne says, and there are lots of boulders on the Moon.
- The most likely outcome is that as the rover gets closer to the object, it will become apparent that it's a boulder or multiple boulders that only appear square due to light, shadow, and distance. And really, that would make it one of the more minor instances of extraplanetary pareidolia, that is, seeing patterns that don't exist.
The "Face on Mars" illusion dispelled by the Mars Reconnaissance Orbiter imaging the same mesa in Cydonia from a different angle. NASAThe famous "Face on Mars" in the Cydonia region of the Red Planet as imaged by the Viking 1 orbiter.NASA/JPLThe Moon Cube, "Mystery Hut," or "Mystery House" on the dark side of the Moon Our Space
In 1976, the Viking 1 orbiter took a photo of a rock in the Cydonia region of Mars that looked an awful lot like a face. Humans are neurologically primed to see faces, reading faces being pretty crucial for human survival, so it's not surprising some people would see a face somewhere on Mars. It was still just rocks, light, and shadow.
The "Face on Mars" illusion dispelled by the Mars Reconnaissance Orbiter imaging the same mesa in Cydonia from a different angle. NASA
"The 'Face on Mars' is a perfect example of pareidolia," Byrne says, but there are other examples, including what some people say looks like Han Solo encased in carbonite on Mercury or a giant tick on Venus
The newly formed Moon may have tidally
heated the Earth
Sometimes the rising Moon looks huge over the horizon, big enough that you could almost fall into it. That's an illusion, though. Your brain is tricking you into thinking it's bigger than it really is.
But, if you had seen the rising Moon, oh, say, 4.4 billion years ago, it would've been immense on the horizon. Shortly after it formed it was much, much closer to Earth, and would have appeared 15 times bigger in the sky than it does now.
This, it turns out, may also help solve a long-standing and pernicious astronomical problem: Why wasn't the Earth frozen solid when it was young?
When the Earth was very young, a few million years after it first formed, it was very hot. Certainly after a Mars-sized planet whacked us but good and formed the Moon, the Earth was heated substantially again. But after that it would've cooled.
The thing is, stars like the Sun get hotter with age. Around the time the Moon formed, roughly 70 million years after Earth did, the Sun was only about 70% as luminous as it is today, getting warmer and brighter by roughly 6% every billion years. That means Earth wasn't receiving nearly as much heat then as it is now. The surface should've been frozen.
But we see lots of evidence of liquid water from back then; minerals and rock formations that indicate they were submerged when they formed. Somehow, Earth's temperature remained somewhat stable over the eons despite the Sun getting hotter. This is called the Faint Young Sun Paradox.
There must have been some other source - or more likely, sources plural - of heat to keep the Earth clement. Some ideas put forth are excessive greenhouse gases in the atmosphere; a more massive young Sun which would've made it hotter back then, with the mass lost through a more powerful solar wind; radioactive elements inside the Earth adding heat; and more. It's not at all clear what that source may have been, though.
In a new paper, a team of scientists proposes a significant source of heating may have been the Moon.
The Moon heats the Earth even today, though only a wee bit, through tides. The two interact gravitationally in weird and subtle ways - I've written a fairly thorough explanation of it - but in a nutshell the gravity of the Moon stretches the Earth, causing the tides. As the Earth rotates the tidal bulges generate internal heat through friction, warming the planet's interior, which makes its way out to the surface. Some effects of this are that it slows the Earth's rotation, and the Moon recedes from the Earth by about 4 centimeters per year; roughly the same speed your fingernails grow.
This tidal effect is enormously dependent on distance. The strength weakens with the cube of the Moon's distance, so double the Moon's distance and the tidal force drops by a factor of 2 x 2 x 2 = 8 times.
Right after it formed, the Moon may have been as close to the Earth as 24,000 kilometers. That's ~15 times closer than its current distance of about 380,000 km. This means that right after it formed the tidal effects would've been staggering, well over 3,000 times what they are now.
Think on that: The current ocean tides are currently* about 0.6 meters in height on average. But back then they would've been 3,000 time higher or nearly 2 kilometers. In some places they would've been much higher, too, depending on the shapes of continents at the time. The surface of the Earth would've been an apocalyptic mess, given our day was only a couple of hours long back then, meaning there would've been these enormous tides sweeping over the planet once every hour or so! Yikes.
Most models of tidal heating show the Moon's contribution to Earth's warmth was small even shortly after it formed. However, the authors of the new work claim these models are oversimplified - in the models' defense this calculation is extremely difficult and filled with unknown factors. Still, they decided to do a more detailed analysis of tidal heating than has been done before.
James Webb Space Telescope will See the Dawn of Starlight
James Webb Space Telescope Launches on Journey to See the Dawn of Starlight
Astronomers were jubilant as the spacecraft made it off the launchpad following decades of delays and cost overruns. The Webb is set to offer a new keyhole into the earliest moments of our universe.
The James Webb Space Telescope launching into space aboard an Ariane 5 rocket on Christmas morning from the Guiana Space Center in French Guiana.Credit...Jody Amiet/Agence France-Presse - Getty Images
The dreams and work of a generation of astronomers headed for an orbit around the sun on Saturday in the form of the biggest and most expensive space-based observatory ever built. The James Webb Space Telescope, a joint effort of NASA, the European Space Agency and the Canadian Space Agency, lifted off from a spaceport near the Equator in Kourou, French Guiana, a teetering pillar of fire and smoke embarking on a million-mile trip to the morning of time.
"The world gave us this telescope and we're handing it back to the world today," said Gregory Robinson, the Webb telescope's program director, during a post-launch news conference in French Guiana.
The telescope, named for the NASA administrator who led the space agency through the early years of the Apollo program, is designed to see farther in space and further back in time than the vaunted Hubble Space Telescope. Its primary light gathering mirror is 21 feet across, about three times bigger than Hubble, and seven times more sensitive.
The Webb's mission is to seek out the earliest, most distant stars and galaxies, which appeared 13.7 billion years ago, burning their way out of a fog leftover from the Big Bang (which occurred 13.8 billion years ago). Astronomers watching the launch remotely from all over the world, many Zooming together in their pajamas, were jubilant. "What an incredible Christmas present," said Garth Illingworth of the University of California, Santa Cruz.
Tod Lauer of the National Science Foundation's NOIRLab, in an email exchange with other astronomers reported his feeling about the launch: "Just enjoying the most sacred of all space words, "Nominal!" he said, referring to the lingo used by launch teams to describe rockets operating as expected.
To which Alan Dressler, a Carnegie Observatory astronomer and one of the founders of the Webb telescope project, replied, "Hallelujah! - another sacred word for the moment, Tod."Priyamvada Natarajan, a cosmologist at Yale, emailed from India to describe herself as "Just utterly utterly elated! - wow! wow!"
In Baltimore at the Space Telescope Science Institute, the headquarters for Webb's mission operations, a small group of scientists and NASA officials erupted in screams of joy and applauded during the launch.
The flight operations team in another part of the institute then watched as Webb deployed its solar array, then its communications antenna minutes later. Roughly 100 mission personnel will command the spacecraft's deployments, alternating between 12 hour shifts 24 hours a day as it begins its journey to a point beyond the moon.
"They've got real work to do," said Kenneth Sembach, the institute's director. "Our teams have spent the last two years doing numerous rehearsals."
NASA's James Webb Space Telescope is named for a former director of the American space agency (AFP/HO)
Equipped with detectors sensitive to infrared or "heat radiation," the telescope will paint the universe in colors no human eye has ever seen. The expansion of the universe shifts the visible light from the earliest, most distant galaxies into the longer infrared wavelengths.
Studying the heat from these infant galaxies, astronomers say, could provide important clues to when and how the supermassive black holes that squat in the centers of galaxies form. Closer to home in the present, the telescope will sniff at the atmospheres of planets orbiting nearby stars, looking for the infrared signatures of elements and molecules associated with life, like oxygen and water.
The Webb will examine all of cosmic history, billions of years of it, astronomers say - from the first stars to life in the solar system. This week, the NASA administrator Bill Nelson called the telescope a "keyhole into the past."
"It is a shining example of what we can accomplish when we dream big," he said. After the launch he said, "It's a great day for planet Earth." The beginning of the telescope's journey did not go unnoticed by the space agency's paymasters in Congress, who have stuck with the project for decades now.
"Today's successful launch of the James Webb Space Telescope marks a historic milestone in our advancement of astrophysics and space science," said Representative Eddie Bernice Johnson, Democrat of Texas and chairwoman of the House Science, Space, and Technology Committee, in a news release.
Saturday's successful launch caps an expensive effort that stretched over 25 years of uncertainty, mistakes and ingenuity. Webb's 18 gold-plated hexagonal mirrors, advanced temperature controllers and ultrasensitive infrared sensors were pieced together in a development timeline filled with cost overruns and technical hurdles. Engineers had to invent 10 new technologies along the way to make the telescope far more sensitive than Hubble.
When NASA picked the Northrop Grumman company to lead Webb's construction in 2002, mission managers estimated that it would cost $1 billion to $3.5 billion and launch to space in 2010. Over-optimistic schedule projections, occasional development accidents and disorganized cost reporting dragged out the timeline to 2021 and ballooned the overall cost to $10 billion.
Even its final lap to the launchpad seemed perilous as a mishap in the Kourou rocket bay, disconnected cables and worrisome weather reports moved the Webb's departure date deeper into December, until a Christmas morning launch could not be avoided.
"I'm so happy today," said Josef Aschbacher, director general of the European Space Agency. But he added, "It's very nerve racking, I couldn't do launches every single day, this would not be good for my life expectancy." For astronomers and engineers, the launch was also a suspenseful sight to take in.
"It was hard to sleep last night," said Adam Riess, an astrophysicist and Nobel laureate who will use the Webb telescope to measure the expansion rate of the universe. "It's 7 a.m. on Christmas and I'm awake and everyone is excited- is this what having kids is like?" Lucianne Walkowicz, an astronomer at the Adler Planetarium in Chicago, wrote on Twitter. They added, "Terrible, I'm going back to sleep," which they confirmed in an email they did, but not before the solar array deployed.
But the launch itself is only the first step in an even more treacherous journey that astronomers and rocket engineers have called "six months of anxiety." The solar panel deployment half an hour into the flight was the first in a monthlong series of maneuvers and deployments with what NASA calls "344 single points of failure."
"I could finally start breathing again when the solar arrays came out," said Pam Melroy, NASA's deputy administrator. "We have so many hard days ahead of us, but you can't even get started on any of that until this part goes perfectly."
Among the most tense moments, astronomers say, will be the unfolding of a giant sunscreen, the size of a tennis court, designed to keep the telescope in the dark and cold enough so that its own heat doesn't swamp the heat from distant stars. The screen is made of five layers of a plastic called Kapton, which is similar to mylar, and as flimsy as mylar. It has occasionally ripped during rehearsals of its deployment.
If all goes well, astronomers will start to see the universe in a new light next summer. They are most looking forward to what they didn't expect. As Thomas Zurbuchen, NASA's associate administrator for science, said recently: "Every time we launch a big bold telescope, we get a surprise. This one is the biggest and boldest yet."
But if anything goes wrong in the coming weeks and months, the field of astronomy's view of the origins of existence may be imperiled. When problems snarled the work of the Hubble in the 1990s, NASA sent astronauts in the space shuttles to perform repair work. The Webb telescope is headed to a point beyond the moon where no spacecraft has ever carried humans before (although Ms. Melroy says NASA has contemplated a robotic repair mission if one were needed).
"I tell friends of mine who are not astronomers, after the launch, you mostly want to hear 30 days of nothing," Dr. Riess said. "And we'll be really happy if we hear nothing."
"30 days of terror": The James Webb telescope's troubles are just beginning, the launch is the easy part.
The James Webb Space Telescope folded for launchJODY AMIET/AFP/Getty ImagesThe five layers of the James Webb Space Telescope sunshade.NASA
Unlike the Hubble telescope, the Webb telescope won't sit in low Earth orbit. Instead, it will take up a position more than a million miles away at Lagrangian point 2 (L2), a place where Earth's gravity and the Sun's gravity cancel out, allowing the Webb to keep Earth constantly at its back as the telescope orbits our star.
NASA designed Webb to see into the deep and ancient reaches of the cosmos in the infrared spectrum, making it essential the Webb telescope be kept cold and out of direct Sun and Moonlight, and L2 is the perfect perch. But flying to L2 also means there's no hope of a repair crew coming to aid the Webb the way Space Shuttle astronauts famously repaired Hubble's blurry optics in 1993.
"This telescope is not designed to be a serviceable mission," Heidi Hammel, an interdisciplinary scientist on the James Webb Space Telescope project, tells Inverse. "So we're designing it to work, not to send it up and try it."
NASA's caution with Webb's launch stems from all that has to go right for it to work in space. It's not just the rocket launch, which Hammel admits is always a little nerve-wracking, "We're putting this precious telescope that we've been building for 20 years now on top of a big, giant rocket and lighting the fuse."
But the anxiety really begins once the Webb reaches space, and begins the complicated dance of activations and deployments necessary for its success. Much of it depends on some alarmingly analog bits of technology. And even once at L2, the telescope will face weeks of calibration before scientists can rest easy, roll up their sleeves, and get to the work of any actual science.
Whenever it occurs, Webb's launch is just the end of the very long first episode. There's an even more prolonged saga ahead - and Hammel and other scientists and engineers like her will be hanging on every beat.
What is the James Webb Space Telescope?
The Hubble and Webb telescopes are both Cassegrain reflector-type telescopes. They use a primary mirror to collect light and focus it on a secondary mirror, focusing that light on instruments to create an image.
The bigger the primary mirror, the more powerful the telescope: One reason scientists are excited about the Webb is that its primary mirror is 21-feet in diameter, compared to Hubble's seven feet.
But 21 feet is too wide to fit inside the fairing, or nose cone, of a rocket. So the Webb primary mirror is built of 18 segments, each of which can be individually adjusted, and which are divided into two foldable wings and a central section to make for a compact launch configuration.
Webb also utilizes a multi-layered, mylar-like sunshade to keep sunlight from blinding its sensitive instruments. The tennis court-size sunshade assembly also rolls up and folds for launch - but must unfold in just the right manner once the telescope is aloft. Folded up for launch like space telescope origami, "there are cables and wires and pulleys and little actuators that pop so that things open," Hammel says.
All of those things must go off without a hitch while the telescope speeds away to a point a million miles from Earth, a month-long journey you might call the 30 Days of Terror, though NASA, Hammel says, prefers the more palatable "30 Days on the Edge."
"We have a very precise timeline of when things have to happen," she says. "We'll be watching and listening very carefully."
There really is water on the Moon - and it might be much more widespread than previously suspected. The findings of two separate studies, published today in the journal Nature Astronomy, are a major boost for plans to send humans back to the Moon.