Connect with us

Science

How the Webb telescope will show us planets like never before – Inverse

Published

 on


When the James Webb Space Telescope (JWST) begins operations over the summer, it will be training the largest, most powerful set of mirrors and instruments ever launched into space on some of the most distant and fascinating targets in the cosmo: The very first stars and galaxies to form in our universe, of course, but also exoplanets.

JWST is not really an exoplanet hunter, but with its 6.5-meter diameter primary mirror and infrared spectroscopy instruments, it’s perfectly suited to peer more closely at these distant worlds than ever before. Telling us what they are made of and, potentially, if there are signs of life in their atmospheres.

Cornell astrophysicist Nikole Lewis says she plans to devote some of her JWST observing time to a “deep field” exploration WASP-17b. It’s a “hot Jupiter” exoplanet about 1,000 light years from Earth. The telescope will spend “80 hours looking at a single planet in all directions using a broad range of instruments, which will allow us to start to understand what the different parts of the planet look like,” Lewis tells Inverse. Combining measurements of temperature, cloud structure, and atmospheric chemistry, “we’re going to really be able to paint a 3-D picture of what this particular hot Jupiter WASP-17b looks like,” she says.

An artist’s conception of “hot Jupiter” exoplanets WASP-12b, WASP-6b, WASP-31b, WASP-39b, HD 189733b, HAT-P-12b, WASP-17b, WASP-19b, HAT-P-1b and HD 209458b.NASA

And what will such an exoplanet look like? Paradoxically, it will look like not much at all and like nothing we’ve seen before. It’s a bit complicated, but the results may yet reframe our understanding of our place in the universe.

What will exoplanets look like to JWST?

“Full disclosure,” Lewis says, “we’re not going to get pretty pictures of exoplanets.” JWST is big and powerful and will see billions of years into the past, but resolving a distant exoplanet next to its star so that it looks like a Hubble or Voyager image of a planet in our Solar System is still far beyond its powers.

We’ll see exoplanets directly, Lewis says, the larger ones anyway, but they’ll appear as “just one bright dot.”

Don’t get disappointed. That dot is just the beginning. JWST will help build a more complex picture of distant exoplanets over time by mapping them in more detail than ever before and looking at neglected wavelengths.

“When we look at planets, we think of them as they look like in optical because of the light reflected off of them,” Lewis says. “But if you really want to tease into what makes them tick, you want to look at them in the infrared,” like if you want to know if there are organic compounds in their atmospheres.

The venerable Hubble Space Telescope has done amazing astronomy, but it sees primarily in the optical, UV, and near-infrared wavelengths. The now-retired Spitzer Space Telescope was tuned to the infrared, but it was retired in 2020, and while Lewis points out it conducted great exoplanet astronomy, it was never designed for such a mission.

There are also ground-based telescopes that can see in the infrared, but certain wavelengths are inaccessible to them due to the filtering effects of Earth’s atmosphere. All together, that means “We were able to find chemical fingerprints in the atmosphere,” of exoplanets, Lewis says, “But in almost all cases, we treat the atmosphere as being uniform, homogenous, we treat it as a one-dimensional object basically.”

Based in space and optimized for a wide swath of the infrared spectrum, Webb will provide data scientists can use to create truly multi-dimensional models of exoplanets. To understand how their atmospheres are structured and what makes up their composition.

“We’re going to be able to look at signatures from things like carbon dioxide, carbon monoxide, methane, all sorts of fun species,” Lewis says. “We can start to move away from that one-dimensional view of the planet and start to understand what it looks like in two in three dimensions.”

What will our Solar System look like to JWST?

While Webb’s capacity to study the most extremely distant objects in the universe rightfully garners a lot of attention and excitement, the space telescope will spend a lot of time peering deeply at objects closer to home as well.

Heidi Hammel, an interdisciplinary scientist involved with Webb since the early 2000s, will be using her observing time to look at just about everything visible in our Solar System outside the orbit of the Moon, from Mars, to asteroids, the outer planets, and even the strange frigid worlds of the Kuiper belt.

She may be most excited about viewing Uranus. The ringed and tilted ice giant planet has only been visited once by Voyager 2 in 1986, and it just so happens it orbits at just the right distance for an optimal field of view for Webb. We really will get some great photos of Uranus with Webb, though, of course, they’ll be in infrared.

In explaining what Uranus will look like through Webb, she refers to a collection of images of the gas giant taken by Hubble, the Keck Observatory, and the European Very Large Telescope (VLT). The blue and pinkish cloud tops are visible in the optical and near-infrared images taken by Hubble and Keck, but the mid-infrared images taken by the VLT appear like somewhat blurry, blunted Eyes of Sauron, or a lump of hot coal in the back of a furnace.

Views of Uranus
Views of Uranus in multiple wavelengths. NASA

“Webb will have better image quality,” Hammel says. “We’ll be able to tighten up these images, and then they won’t look so mottled.”

Webb will allow Hammel and other planetary scientists to better understand how Uranus’s upper and lower atmospheres interact. Webb’s spectrometer will enable them to map the planet’s chemical composition like never before.

“Where is methane coming from? Where is ethane coming from?” Hammel says. “We’re going to be able to tease out this chemistry as a function of altitude, and figure out the linkages.

Why it matters— It’s not a coincidence that scientists looking at distant exoplanets and planets in our backyard are all interested in the spectra and chemical composition of their targets. Such observations don’t always provide immediately stunning visual images you can slap on a poster as you can with many Hubble images, but over time they can help scientists paint a broader, deeper conceptual picture of how all planets and solar systems work, including our own.

Scientists spend a lot of time trying to answer questions about how we got here, Lewis says.

How did our solar system form? How did Earth turn out to be the only habitable planet in the Solar System?

“But we’ve always had just a sample of eight things to compare to, right? And now we’re going to have a sample of 300 to 400 things,” she says. “That allows us to test our models of the physics and chemistry of what makes planets tick.”

Adblock test (Why?)



Source link

Continue Reading

Science

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

Published

 on


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.”

Adblock test (Why?)



Source link

Continue Reading

Science

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

Published

 on


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.

Adblock test (Why?)



Source link

Continue Reading

Science

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

Published

 on


play
Show Caption

Hide Caption

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)

AP

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.”

Adblock test (Why?)



Source link

Continue Reading

Trending