When it comes to building enormous, complex space telescopes, agencies like NASA have to plan far in advance. Even though the James Webb Space Telescope only launched recently, astronomers are already busy thinking about what will come after Webb — and they’ve got ambitious plans.
The big plan for the next decades of astronomy research is to find habitable planets, and maybe even to search for signs of life beyond Earth. That’s the lofty goal of the Habitable Worlds Observatory, a space telescope currently in the planning phase that is aimed at discovering 25 Earth-like planets around sun-like stars.
We spoke to two of the scientists working on plans for this next-generation space telescope to find out more.
The power of direct imaging
One of the big challenges in finding habitable planets beyond our solar system is this: We can rarely actually see these far-off planets directly, because planets are so small and dim compared to stars. So to identify an exoplanet, astronomers generally infer its existence due to its effects on its host star. Currently, tools like the Hubble or James Webb space telescopes most often look for dips in a star’s brightness when a planet passes in front of it, called a transit, or they look for a wobble of the star caused by the gravity of the planet, called the radial velocity method.
“This is a multigenerational, probably multi-century endeavor that we’re on.”
Those methods give us clues, but to really understand exoplanets in depth, we need to be able to image them directly. Current telescopes are rarely able to do this because it requires such a high level of precision, but scientists are already planning out a next generation of space telescopes that will be able to take images of exoplanets.
The next big space telescope to be launched is the Nancy Grace Roman Space Telescope, scheduled to launch in 2027. It will perform a survey of the sky to estimate how many habitable exoplanets are out there. After that comes the Habitable World Observatory, a planned space telescope that will directly image Earth-like exoplanets around sun-like stars and which should launch around 2040. This will be the best chance we’ll have to date of discovering habitable Earth-like worlds where we could search for evidence of life beyond Earth.
Choosing the right wavelength
If you’ve followed the news about the James Webb Space Telescope, you’ve likely heard that it looks in the infrared part of the electromagnetic spectrum. That’s essential for its goal of studying the earliest galaxies, as it allows scientists to see galaxies with high levels of redshift. Infrared is also useful for looking through clouds of dust and seeing structures that would otherwise be hidden.
The plan for the Habitable Worlds Observatory, however, is to look in the optical and ultraviolet wavelengths. These wavelengths are useful for identifying the signatures of specific atoms such as hydrogen or oxygen, so we can point our instruments toward a planet and learn what its atmosphere is composed of.
There are all sorts of options for what particular atoms or compounds we could look for, but oxygen is the leading choice right now for what is called a biomarker, or a clue that indicates the potential presence of life. Spotting oxygen on a distant planet may be a sign that it warrants further inspection.
“There’s no perfect biomarker signature,” said David Sing of Johns Hopkins University, as we could also look for atoms like methane, and there’s always the possibility of a false positive, “but oxygen is a really important one.”
Oxygen also gives off a very strong signal, which makes it relatively easier to detect. In particular, ozone — which is a variation of oxygen with three atoms bound together — has a very strong signature in the ultraviolet wavelength. Think about how the ozone layer on Earth protects us from the ultraviolet radiation from the sun, and you can see how scientists could infer the presence of ozone on a distant planet if they saw a particular wavelength of ultraviolet light being blocked.
How to build an optical/UV telescope
With its focus on optical and ultraviolet wavelengths, the Habitable Worlds Observatory will be more similar to the Hubble Space Telescope than the James Webb Space Telescope. And that brings some advantages in terms of how you build a telescope.
Infrared telescopes like Webb are very sensitive to temperature (because when things get hot, they give off infrared radiation). So to work accurately, Webb needs to be cooled to extremely low operating temperatures of just a few Kelvin for some instruments. That makes the telescope more complex and expensive to build, as it requires a cryogenic cooling system.
For a telescope like the Habitable Worlds Observatory, that kind of extreme cooling isn’t necessary, which helps to keep the costs down.
NASA
Another key difference between infrared telescopes like Webb and optical/ultraviolet telescopes like the Habitable Worlds Observatory is the mirror. Webb’s primary mirror is coated with gold, which reflects infrared light very well. But an optical/ultraviolet telescope has a mirror coated with silver, which is more efficient at reflecting those wavelengths.
New technologies for a new decade
In some ways, we already know exactly what sorts of instruments will be required to look for habitable worlds, as these are updates to existing instruments rather than entirely new concepts.
For example, the instruments on Habitable Worlds will be somewhat similar to those on James Webb or Hubble, as they will consist of cameras and spectrographs. The cameras will be used to look for exoplanets in other star systems, and once a planet has been identified, it can be studied in more depth using the spectrographs. Spectrographs work by splitting incoming light into different wavelengths, to see which wavelengths have been absorbed. That tells you what the object that you’re looking at is composed of — and that’s how you can see whether an exoplanet has an atmosphere, and what that atmosphere is made of.
NASA
Refining these instruments and making them more accurate is not a trivial endeavor. In addition to direct detection, the next generation of space telescopes will also use techniques like radial velocity for identifying exoplanets. And more accurate spectrographs will enable techniques like extreme precision radial velocity, which allows more accurate measurements of the masses of exoplanets orbiting sun-like stars.
But more theoretical advances are required as well. One major factor required to improve our understanding of exoplanets, for example, is improving our understanding of stars. Stars can become brighter or dimmer for all sorts of reasons, and we need to be able to model this more accurately if we want to determine whether a variation is caused by the presence of an exoplanet, or is due to variation of the star.
Hunting for habitability
Even with a brand-new telescope equipped with brand-new technology, however, it won’t be a simple matter to find life beyond our solar system. That’s because habitability is a complex concept that requires more than just identifying an Earth-like planet orbiting a sun-like star.
“A planet that looks like it’s about the right brightness to be an Earth-sized planet, that has a roughly circular orbit in what we would call the habitable zone, shows some evidence for water vapor, maybe some oxygen, there’s no inner giant planet that has stirred things up, the star isn’t too active — that’s the kind of system we’re hoping to find as a candidate for a potentially habitable planet,” Scott Gaudi of the Ohio State University said.
NASA
But as tempting as it is to imagine a scenario where we build this telescope, find a habitable planet, then immediately detect life, that’s not how this will work, Gaudi said.
To properly search for habitable exoplanets, “we really have to get the whole context, which means studying the other planets in the systems, the debris disks, studying the stars,” Gaudi said. “That’s what’s really going to help us understand whether or not these planets are truly habitable.”
There’s a temptation to imagine that “we’re going to build the Habitable Worlds Observatory, we’re going to find life, and we’re done,” Gaudi said, but “it’s not going to work that way. If we’re lucky, we’re going to find one or two, maybe three, systems that look pretty promising. And then we’re going to have to build something even bigger and better.”
A multigenerational endeavor
Even if we’re able to find the ideal-looking system with a potentially habitable Earth-like world, then the next step would be to look at even more advanced factors, such as how much of the planet is covered by oceans and how much is land mass. Searching for life isn’t something that is going to be solved any time soon, but scientists are now laying the groundwork for Habitable Worlds Observatory to take on the next part of the job in 20 years’ time.
That’s similar to the way that planning for the James Webb Space Telescope began around 2000, and scientists today are just starting to be able to use this tool for discovery.
“Several decades ago, I was just a young student. But I’ve reaped the rewards of all that hard work that people did at the time,” Sing said. “And that generation of scientists felt that way because people did it for them with the Hubble Space Telescope. So there’s this legacy where you’re reaping the rewards of what senior scientists did 20 years ago. And you want to make sure that legacy will continue 20 years from now.”
NASA
Because wondering whether life could exist beyond Earth is one of the most profound questions facing science today, and it won’t be solved quickly. The Habitable Worlds Observatory is the next step on that journey, but it won’t be the end point.
“This is a multigenerational, probably multi-century endeavor that we’re on,” Gaudi said. “And I think that we should be optimistic about that process, but we should also be humble.”
More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.
That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.
“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”
The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.
Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.
Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.
Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.
Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.
Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.
“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”
The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.
North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.
Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”
Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.
Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.
For Dello, the “fingerprints of climate change” were clear.
“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”
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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.
On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.
They call it “Big Sam.”
The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.
It didn’t die alone.
“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.
She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”
“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.
The head alone, she said, is about the size of a baby elephant.
The discovery was a long time coming.
The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.
“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.
When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”
“It contains about 100 to 300 bones per square metre,” she said.
Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.
About a year ago, they found the second adult: Big Sam.
Bamforth said both dinosaurs are believed to have been the elders in the herd.
“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.
“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”
The genders of the two adults are unknown.
Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.
The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.
She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.
“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.
“It’s pretty exciting.”
This report by The Canadian Press was first published Sept. 25, 2024.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
