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Biggest astronomical happenings of the decade



What a decade it’s been for astronomy and space! The Earth tied its all-time record for 10 full orbits around the Sun, long-term missions like New Horizons, Kepler, and Hubble produced years of results, and more photons than ever before poured into the CCDs of telescopes peering into the heavens.

Unfortunately, it hasn’t all been progress. Many ambitious projects are stalled for lack of funding (or other reasons), the U.S. currently has no means of conveyance into orbit for manned missions, and humankind’s scoreboard for “number of planets visited” remains stubbornly pegged at 1.5 for the fiftieth straight year (moons count for half).

So come along with us as we recount the celestial heights and cold soundless voids of the past decade in space, in a highly subjective and incomplete fashion.


Last space shuttle flight

After 135 missions, the Space Shuttle program flew for the final time. The shuttle was used to deploy and repair instruments like the Hubble Observatory over the course of its 30-year run, and the U.S. still does not have a way to get its brave astro-men and -women into space (other than renting Russian space jalopies).


Transit of Venus

From our perspective on Earth, Venus passes directly in front of the disk of the sun only twice every 120 years or so. These events, called transits, happen in pairs separated by eight years. 2012 was the second of one of these pairs — prior to 2004, the previous set was in 1874 and 1882.

In previous centuries, observing these events from different locations on Earth was used to measure the size of the solar system by triangulation. This time around it was just for show, but it was still pretty cool.


Chelyabinsk meteor

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There are a lot of car accident scams and corrupt cops in Russia, so basically everyone there has dashcams. Which comes in very handy when the bright fireball from a meteor burning up in the atmosphere happens over Russia, because it means we got to see dozens of videos of the blast.

The meteoroid itself was heavier than the Eiffel Tower, and the largest impact since the 1908 Tunguska explosion. About 1,500 people reported injuries (mostly from windows broken by the shockwave), but thankfully no one was killed.

Planck results

The ESA’s Planck mission mapped tiny variations in the temperature of light emitted shortly* after the Big Bang, when the universe still had that new car smell. Studying these variations, known as the “anisotropy of the cosmic microwave background,” allows scientists to find the age of the universe, its rate of expansion, and a bunch of other things about its contents. These results (which were further refined two years later) are the current cosmological benchmark.

*(if you call 380,000 years “shortly”… which you do, if you’re the universe)


BICEP2 detects gravitational waves from the early universe — or maybe not

The BICEP experiment measured polarization in that cosmic microwave background signal. If certain theories of cosmic inflation are right, it ought to have created gravitational waves that would make a polarization signal in that relic radiation.

Initially, BICEP claimed they had observed such a signal, but it later came to light that the team had scraped a map of cosmic dust from the PDF of a conference talk to calibrate the sky’s dust pattern. That didn’t work, because it wasn’t really accurate enough for that kind of purpose, and the result didn’t hold up.


New Horizons gets to Pluto

After flying through space for nine years, faster than any other man-made object ever, New Horizons streamed past the solar system’s most conspicuous former planet.


Gravitational waves observed for real

Image: T. Pyle/LIGO

LIGO successfully observed the space-warping effects of two black holes spiraling into each other. Some of the energy from the collision was transported away from the scene of the incident in the form of ripples in spacetime, seen on Earth in the minuscule expansion and contraction of a couple of 4 km-long tubes filled with lasers.



The first discovery of an object foreign to our solar system was observed passing through it on a hyperbolic orbital trajectory. Additional observations seemed to indicate that it was approximately cigar-shaped and tumbling end over end … and that it was almost certainly not some kind of alien probe.

Solar eclipse

In August, a total solar eclipse swept through much of the contiguous United States. Skies grew dark at midday, animals panicked, and President Donald Trump boldly defied the small-minded busybodies of the astronomical and medical establishments by choosing to look directly at it.


Direct image of a black hole

Radio astronomers observing the black hole at the center of the Messier 87 galaxy created the first detailed image of material heated as it falls into the massive gravity well. The image distinctly shows a central accretion disk tipped toward us, and a glowing halo surrounding the event horizon. Perhaps best of all, it looks exactly the way you would like a black hole to look.

Honorable Mentions

2012:  Contrary to John Cusack and a total misunderstanding of the Mayan calendar, the world does not end.

2017Felix Baumgartner jumps out of space at the behest of Red Bull ad execs.

2019:  Foreshadowing what is sure to be some kind of nervous breakdown, Elon Musk launches a car into space for some reason. Our parents got the Apollo mission, but I guess this is okay, too.

AIPT Science is co-presented by AIPT and the New York City Skeptics.

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Scientists study trajectory of meteorite that landed in B.C. in October – Red Deer Advocate



VANCOUVER — Scientistsstudying a meteorite that landed next to a British Columbia woman’s head last year say it was diverted to that path about 470 million years ago.

The small meteorite broke through a woman’s ceiling in Golden, B.C., in October, landing on her pillow, next to where she had been sleeping moments earlier.

Philip McCausland,a lead researcher mapping the meteorite’s journey, said Monday they know the 4.5-billion-year-old rock collided with something about 470 million years ago, breaking into fragments and changing the trajectory of some of the pieces.

McCausland, who’s an adjunct professor at Western University in London, Ont., said the meteorite is of scientific significance because it will allow scientists to study how material from the asteroid belt arrives on Earth.

“There’s 50,000 to 60,000 identified meteorites now in the world, but most have no context. We don’t know really where they came from,” he said.

“In cases where we have known orbits, where they were observed coming in well enough that we can reconstruct what the orbit was before it hit the Earth’s atmosphere, we can actually (determine) where they came from in the asteroid belt. Golden is one of those,” he said, referring to the location of where the meteorite landed.

Researchers determined the meteorite is an L chondrite, one of the most commonly found types of meteorites to fall to Earth. Despite this, he said only about five L chondrites have known orbits.

He said the Canadian team is now working with scientists in Switzerland, the U.K., U.S. and Italy to learn more about the meteorite and its path to Golden.

“We know we’re still going to get something interesting out of this,” McCausland said. “We actually do want to get a good handle on how things get delivered from the asteroid belt, and this is a useful part of putting that together.”

Most of the meteorite has been returned to Ruth Hamilton, the woman who had the close call, and McCausland said it’s up to her to decide what to do with it.

Whether she decides to keep, sell or donate the rock, he said there is cultural significance of the rock to Canada. If she sells it to an international buyer, she would be required to go through the exportation process, he said.

Hamilton said she hasn’t yet made up her mind on what to do with the meteor. It’s currently sitting in a safety deposit box.

“I don’t have any plans for it right now, but once they’re done analyzing it, I’ll get all the documentation that proves it’s a meteorite,” she said. “It’s going to be officially named the Golden Meteorite.”

Before her roof is permanently repaired this spring, Hamilton said she intends to remove the section where the meteorite crashed through to keep it preserved alongside the rock.

McCausland said the research will likely conclude in May, and the scientists will then publish their work in an academic journal.

“Whenever something like this happens, I like to tell people it could happen to any of us; anyone can find a meteorite. It’s unlikely one will crash through your roof, but it can happen,” McCausland said. “It’s nature and, if anything, it’s a reminder that we’re part of something bigger.”

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Elon Musk’s Starlink Is Causing More Streaks to Appear in Space Images – Gizmodo



A Starlink satellite streak appears in a ZTF image of the Andromeda galaxy, as pictured on May 19, 2021.
Image: ZTF/Caltech

Researchers at the Zwicky Transient Facility in California have analyzed the degree to which SpaceX’s Starlink satellite constellation is affecting ground-based astronomical observations. The results are mixed.

The new paper, published in The Astrophysical Journal Letters and led by former Caltech postdoctoral scholar Przemek Mróz, offers some good news and some bad news. The good news is that Starlink is not currently causing problems for scientists at the Zwicky Transient Facility (ZTF), which operates out of Caltech’s Palomar Observatory near San Diego. ZTF, using both optical and infrared wavelengths, scans the entire night sky once every two days in an effort to detect sudden changes in space, such as previously unseen asteroids and comets, stars that suddenly go dim, or colliding neutron stars.

But that doesn’t mean Starlink satellites, which provide broadband internet from low Earth orbit, aren’t having an impact. The newly completed study, which reviewed archival data from November 2019 to September 2021, found 5,301 satellite streaks directly attributable to Starlink. Not surprisingly, “the number of affected images is increasing with time as SpaceX deploys more satellites,” but, so far, science operations at ZTF “have not yet been severely affected by satellite streaks, despite the increase in their number observed during the analyzed period,” the astronomers write in their study.

The bad news has to do with the future situation and how satellite megaconstellations, whether Starlink or some other fleet, will affect astronomical observations in the years to come, particularly observations made during the twilight hours. Indeed, images most affected by Starlink were those taken at dawn or dusk. In 2019, this meant satellite streaks in less than 0.5% of all twilight images, but by August 2019 this had escalated to 18%. Starlink satellites orbit at a low altitude of around 324 miles (550 km), causing them to reflect more sunlight during sunset and sunrise, which creates a problem for observatories at twilight.

Astronomers perform observations at dawn and dusk when searching for near-Earth asteroids that might appear next to the Sun from our perspective. Two years ago, ZTF astronomers used this technique to detect 2020 AV2—the first asteroid entirely within the orbit of Venus. A concern expressed in the new paper is that, when Starlink gets to 10,000 satellites—which SpaceX expects to achieve by 2027—all ZTF images taken during twilight will contain at least one satellite streak. Following yesterday’s launch of a Falcon 9 rocket, the Starlink megaconstellation consists of over 2,000 satellites.

In a Caltech press release, Mróz, now at the University of Warsaw in Poland, said he doesn’t “expect Starlink satellites to affect non-twilight images, but if the satellite constellation of other companies goes into higher orbits, this could cause problems for non-twilight observations.” A pending satellite constellation managed by OneWeb, a UK-based telecommunications firm, will orbit at an operational altitude of 745 miles (1,200 km), for example.

Launch of a SpaceX Falcon 9 rocket with 49 Starlink satellites on board, as imaged on January 18, 2022.
Launch of a SpaceX Falcon 9 rocket with 49 Starlink satellites on board, as imaged on January 18, 2022.
Photo: SpaceX

The researchers also estimated the fraction of pixels that are lost as a result of a single satellite streak, finding it to be “not large.” By “not large” they mean 0.1% of all pixels in a single ZTF image.

That said, “simply counting pixels affected by satellite streaks does not capture the entirety of the problem, for example resources that are required to identify satellite streaks and mask them out or the chance of missing a first detection of an object,” the scientists write. Indeed, as Thomas Prince, an astronomer at Caltech and a co-author of the study pointed out in the press release, a “small chance” exists that “we would miss an asteroid or another event hidden behind a satellite streak, but compared to the impact of weather, such as a cloudy sky, these are rather small effects for ZTF.”

SpaceX has not responded to our request for comment.

The scientists also looked into the measures taken by SpaceX to reduce the brightness of Starlink satellites. Implemented in 2020, these measures include visors that prevent sunlight from illuminating too much of the satellite’s surface. These measures have served to reduce the brightness of Starlink satellites by a factor of 4.6, which means they’re now at a 6.8 magnitude (for reference, the brightest stars shine at a magnitude 1, and human eyes can’t see objects much dimmer than 6.0). This marks a major improvement, but it’s still not great, as members of the 2020 Satellite Constellations 1 workshop asked that satellites in LEO have magnitudes above 7.

The current study only considered the impacts of Starlink on the Zwicky Transient Facility. Every observatory will be affected differently by Starlink and other satellites, including the upcoming Vera C. Rubin Observatory, which is expected to be badly affected by megaconstellations. Observatories are also expected to experience problems as a result of radio interference, the appearance of ghost-like artifacts, among other potential issues.

More: Elon Musk Tweets Video of ‘Mechazilla’ Tower That Will Somehow Catch a Rocket.

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Earth's core is rapidly cooling, study reveals. Is our planet becoming 'inactive'? – USA TODAY



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Planet Earth hits 6th warmest year on record

Earth simmered to the sixth hottest year on record in 2021, according to several newly released temperature measurements. (Jan. 13)


Earth’s interior is cooling faster than we previously estimated, according to a recent study, prompting questions about how long people can live on the planet.

There’s no exact timetable on the cooling process, which could eventually turn Earth solid, similar to Mars. But results from a new study, published in the peer-reviewed journal Earth and Planetary Science Letters, focuses on how quickly the core may cool by studying bridgmanite, a heat-conducting mineral commonly found at the boundary between the Earth’s core and mantle.

“Our results could give us a new perspective on the evolution of the Earth’s dynamics,”  ETH Zurich professor Motohiko Murakami, the lead author of the study, said in a press release. “They suggest that Earth, like the other rocky planets Mercury and Mars, is cooling and becoming inactive much faster than expected.”

While the process may be moving quicker than previously thought, it’s a timeline that “should be hundreds of millions or even billions of years,” Murakami told USA TODAY.

The boundary between the Earth’s outer core and mantle is where the planet’s internal heat interaction exists. The scientific team studied how much bridgmanite conducts from the Earth’s core and found higher heat flow is coming from the core into the mantle, dissipating the overall heat and cooling much faster than initially thought. 

“This measurement system let us show that the thermal conductivity of bridgmanite is about 1.5 times higher than assumed,” Murakami said in the press release. “We still don’t know enough about these kinds of events to pin down their timing.”

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