One of the best things about being a professional astronomer is having really cool friends. Since I now live on the other side of the world from most of them, my latest project involves Skyping with fun astronomers to talk about their work.
I’m very excited about this latest one, because it features the awesome Moiya McTier (who also featured in the panel following my screening of Galaxy Quest last year) talking about an amazing project figuring out how we might discover mountains on extrasolar planets. This woman is seriously cool!
How ‘Cosmic DNA’ Revealed Exoplanet Siblings Raised In The Same Nursery
“By measuring the rotation rates and masses of stars, we can determine their ages to excellent precisions. This new research takes us a step further: into territory where we can identify large, elongated, diffuse star clusters, even ones spread out across more than a thousand light-years, that we can confidently trace back to a single origin in time. It’s proof that we can identify which stars, even stars separated by great distances, were born together, from the same star-forming region. And it offers hope, for perhaps the first time, that if we can gather enough high-quality data, even 4.5 billion years after the fact, we just might be able to someday find our long-lost stellar siblings as well. With the power of massive data sets, open science, a lot of technique and a little luck, we might soon discover that we’re a lot less lonely in the Universe than we’ve ever imagined.”
Imagine finding two exoplanet systems great distances apart, seemingly unrelated, and without very much in common at all. Would you be able to tell that they came from the same star cluster, hundreds of millions of years before? In the past, we would have had no way to do so.
An Australian mechanic is about to become a published scientific author after he contributed to the discovery of a four-planet solar system during a crowdsourced astronomy event.
Andrew Grey, a 26-year-old from Darwin, took part in the Stargazers Live event broadcast over three nights on the ABC this week.
Astronomers have found evidence for a hot and steamy atmosphere around an Earth-like planet that circles a red dwarf star in the southern sky.
The discovery marks one of the first times that scientists have spotted an atmosphere around a small, rocky world and brings them one step closer to the goal of finding life elsewhere in the universe.
The planet, which lies 39 light years away in the constellation of Vela, is not considered to be habitable itself, but astronomers regard it as a prime candidate for honing the instruments and techniques they will need to detect the existence of alien life on more hospitable worlds.
Not just one, but seven Earth-size planets that could potentially harbor life have been identified orbiting a tiny star not too far away, offering the first realistic opportunity to search for signs of alien life outside the solar system.
The planets orbit a dwarf star named Trappist-1, about 40 light-years, or 235 trillion miles, from Earth. That is quite close in cosmic terms, and by happy accident, the orientation of the orbits of the seven planets allows them to be studied in great detail.
Astronomers have found at least seven Earth-sized planets orbiting the same star 40 light-years away, according to astudy published Wednesday in the journal Nature.
The seven exoplanets were all found in tight formation around an ultracool dwarf star called TRAPPIST-1. Estimates of their mass also indicate that they are rocky planets, rather than being gaseous like Jupiter. Three planets are in the habitable zone of the star, known as TRAPPIST-1e, f and g, and may even have oceans on the surface.
“I think we’ve made a crucial step towards finding if there is life out there,” said Amaury Triaud, one of the study authors and an astronomer at the University of Cambridge. “I don’t think any time before we had the right planets to discover and find out if there was (life). Here, if life managed to thrive and releases gases similar to what we have on Earth, we will know.”
The system is just 40 light-years away. On a cosmic scale, that’s right next door. Of course, practically speaking, it would still take us hundreds of millions of years to get there with today’s technology – but again, it is notable in that the find speaks volumes about the potential for life-as-we-know-it beyond Earth.
The Hubble Space Telescope is already being used to search for atmospheres around the planets, and Emmanuël Jehin, a scientist who also worked on the research, asserts that future telescopes could allow us to truly see into the heart of this system: “With the upcoming generation of telescopes, such as ESO’s European Extremely Large Telescope and the NASA/ESA/CSA James Webb Space Telescope, we will soon be able to search for water and perhaps even evidence of life on these worlds.”
In contrast to our sun, the TRAPPIST-1 star – classified as an ultra-cool dwarf – is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun. The planets also are very close to each other. If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.
The planets may also be tidally locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong winds blowing from the day side to the night side, and extreme temperature changes.
OurSpitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in an area called the habitable zone, where liquid water is most likely to exist on a rocky planet.
Assisted by several ground-based telescopes, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.
This is the FIRST time three terrestrial planets have been found in the habitable zone of a star, and this is the FIRST time we have been able to measure both the masses and the radius for habitable zone Earth-sized planets.
All of these seven planets could have liquid water, key to life as we know it, under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.
At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets. To clarify, exoplanets are planets outside our solar system that orbit a sun-like star.
In this animation, you can see the planets orbiting the star, with the green area representing the famous habitable zone, defined as the range of distance to the star for which an Earth-like planet is the most likely to harbor abundant liquid water on its surface. Planets e, f and g fall in the habitable zone of the star.
Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them. The mass of the seventh and farthest exoplanet has not yet been estimated.
For comparison…if our sun was the size of a basketball, the TRAPPIST-1 star would be the size of a golf ball.
Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces.
The sun at the center of this system is classified as an ultra-cool dwarf and is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun.
The planets also are very close to each other. How close? Well, if a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.
The planets may also be tidally-locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong wind blowing from the day side to the night side, and extreme temperature changes.
Because most TRAPPIST-1 planets are likely to be rocky, and they are very close to one another, scientists view the Galilean moons of Jupiter – lo, Europa, Callisto, Ganymede – as good comparisons in our solar system. All of these moons are also tidally locked to Jupiter. The TRAPPIST-1 star is only slightly wider than Jupiter, yet much warmer.
How Did the Spitzer Space Telescope Detect this System?
Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. Spitzer is uniquely positioned in its orbit to observe enough crossing (aka transits) of the planets in front of the host star to reveal the complex architecture of the system.
Every time a planet passes by, or transits, a star, it blocks out some light. Spitzer measured the dips in light and based on how big the dip, you can determine the size of the planet. The timing of the transits tells you how long it takes for the planet to orbit the star.
The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets. Spitzer, Hubble and Kepler will help astronomers plan for follow-up studies using our upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone and other components of a planet’s atmosphere.
At 40 light-years away, humans won’t be visiting this system in person anytime soon…that said…this poster can help us imagine what it would be like:
Discovering signs of extraterrestrial life in the universe has been a highly sought-after field of inquiry throughout much of scientific history. Finding other life forms, whether they’re microscopic or similar to us, would undoubtedly revolutionize many areas of science and how we understand our place in the cosmos. While no real evidence has been found supporting the existence of extraterrestrial life, there are quite a few institutions dedicated to the search—and that search is continuing to get bigger.
The SETI Institute, one of the pillar institutions for the search, is ramping up its efforts by funding a variety of new initiatives…Continue Reading
Last year, in cooperation with ASU Center for Science and the Imagination, and NASA - National Aeronautics and Space Administration, I had a great chance to create 8 illustrations for the project called “Visions, Ventures, Escape Velocities” - a research-based collection featuring narratives by top science fiction authors and essays by experts on future possibilities for exploring Mars, Asteroids, Low Earth Orbit, and Exoplanets.
A planet in the Clarion Galaxy formerly named UC-4770, has been renamed Adrena-Concava after the first fly by. A first in many ways, “AC” as it’s called by the project team, is the first known concave planet.
“It’s very special” reports Dr. Phylia Weber. “It rocks back and forth as it revolves around its star, which we’ve named Gigante. The concave portion of the planet rocks into the light…
The Nobel Prize in Physics 2019 was awarded “for contributions to our understanding of the evolution of the universe and Earth’s place in the cosmos” with one half to James Peebles “for theoretical discoveries in physical cosmology”, the other half jointly to Michel Mayor and Didier Queloz “for the discovery of an exoplanet orbiting a solar-type star.”
In this post we will try to understand how Michel Mayor and Didier Queloz discovered the first ever exoplanet - 51 Pegasi b . Let’s first take the example of a Leslie speaker.
Leslie Speaker
This speaker has two horns from which the sound emerges out,
The two horns are placed on a rotating platform which can spun at high speeds.
Therefore, if you play a tone at frequency ‘f’ and begin to spin the horns, you can make the listener hear a higher frequency(f1) and a lower frequency tone(f2) instead of ‘f’.
If the horns stop spinning, the listener will only hear frequency ‘f’ .
This is due to the Doppler Effect and leads to some really cool sound effects. This video offers a great demo around the 7:30 mark:
Planet or no planet?
In our solar system the Sun, Earth, and all of the planets in the solar system orbit around a point called the barycenter. This is where the center of the mass of the solar system lies at :
This means that the motion of the sun and jupiter looks like so:
Top and side view (exaggerated for more clarity)
This same ‘wobbling’ idea applies to planets revolving other stars as well (called ‘Exoplanets’).
The star moves around in a circle like the horns of a Leslie speaker.
The spectrum of the star when it is moving towards us would be doppler shifted to a higher frequency and when the star is moving away would be doppler shifted to a lower frequency!
Measuring this wobble is one way to find whether a planet is orbiting the star or not.
Michel Mayor and Didier Queloz were awarded the Nobel prize for their discovery of 51-Pegasi b, an ‘exoplanet’ orbiting a sun-like star 51-Pegasi using this technique.
When they published their results in 1995 it was the first exoplanet to be discovered.
Today more than 4,000 exoplanets are confirmed to be in orbit around other stars but their research definitely stands as the cornerstone in what has now become a field of its own.
How will the James Webb Space Telescope change how we see the universe? Ask an expert!
The James Webb Space Telescope is launching on December 22, 2021. Webb’s revolutionary technology will explore every phase of cosmic history—from within our solar system to the most distant observable galaxies in the early universe, to everything in between. Postdoctoral Research Associate Naomi Rowe-Gurney will be taking your questions about Webb and Webb science in an Answer Time session on Tuesday, December 14 from noon to 1 p.m EST here on our Tumblr!
Dr. Naomi Rowe-Gurney recently completed her PhD at the University of Leicester and is now working at NASA Goddard Space Flight Center as a postdoc through Howard University. As a planetary scientist for the James Webb Space Telescope, she’s an expert on the atmospheres of the ice giants in our solar system — Uranus and Neptune — and how the Webb telescope will be able to learn more about them.
The James Webb Space Telescope – fun facts:
Webb is so big it has to fold origami-style to fit into its rocket and will unfold like a “Transformer” in space.
Webb is about 100 times more powerful than the Hubble Space Telescope and designed to see the infrared, a region Hubble can only peek at.
With unprecedented sensitivity, it will peer back in time over 13.5 billion years to see the first galaxies born after the Big Bang––a part of space we’ve never seen.
It will study galaxies near and far, young and old, to understand how they evolve.
Webb will explore distant worlds and study the atmospheres of planets orbiting other stars, known as exoplanets, searching for chemical fingerprints of possible habitability.
If you’ve spent much time stargazing, you may have noticed that while most stars look white, some are reddish or bluish. Their colors are more than just pretty – they tell us how hot the stars are. Studying their light in greater detail can tell us even more about what they’re like, including whether they have planets. Two women, Williamina Fleming and Annie Jump Cannon, created the system for classifying stars that we use today, and we’re building on their work to map out the universe.
By splitting starlight into spectra – detailed color patterns that often feature lots of dark lines – using a prism, astronomers can figure out a star’s temperature, how long it will burn, how massive it is, and even how big its habitable zone is. Our Sun’s spectrum looks like this:
Astronomers use spectra to categorize stars. Starting at the hottest and most massive, the star classes are O, B, A, F, G (like our Sun), K, M. Sounds like cosmic alphabet soup! But the letters aren’t just random – they largely stem from the work of two famous female astronomers.
Williamina Fleming, who worked as one of the famous “human computers” at the Harvard College Observatory starting in 1879, came up with a way to classify stars into 17 different types (categorized alphabetically A-Q) based on how strong the dark lines in their spectra were. She eventually classified more than 10,000 stars and discovered hundreds of cosmic objects!
That was back before they knew what caused the dark lines in spectra. Soon astronomers discovered that they’re linked to a star’s temperature. Using this newfound knowledge, Annie Jump Cannon – one of Fleming’s protégés – rearranged and simplified stellar classification to include just seven categories (O, B, A, F, G, K, M), ordered from highest to lowest temperature. She also classified more than 350,000 stars!
Type O stars are both the hottest and most massive in the new classification system. These giants can be a thousand times bigger than the Sun! Their lifespans are also around 1,000 times shorter than our Sun’s. They burn through their fuel so fast that they only live for around 10 million years. That’s part of the reason they only make up a tiny fraction of all the stars in the galaxy – they don’t stick around for very long.
As we move down the list from O to M, stars become progressively smaller, cooler, redder, and more common. Their habitable zones also shrink because the stars aren’t putting out as much energy. The plus side is that the tiniest stars can live for a reallylong time – around 100 billion years – because they burn through their fuel so slowly.
Astronomers can also learn about exoplanets – worlds that orbit other stars – by studying starlight. When a planet crosses in front of its host star, different kinds of molecules in the planet’s atmosphere absorb certain wavelengths of light.
By spreading the star’s light into a spectrum, astronomers can see which wavelengths have been absorbed to determine the exoplanet atmosphere’s chemical makeup. Our James Webb Space Telescope will use this method to try to find and study atmospheres around Earth-sized exoplanets – something that has never been done before.
Our upcoming Nancy Grace Roman Space Telescope will study the spectra from entire galaxies to build a 3D map of the cosmos. As light travels through our expanding universe, it stretches and its spectral lines shift toward longer, redder wavelengths. The longer light travels before reaching us, the redder it becomes. Roman will be able to see so far back that we could glimpse some of the first stars and galaxies that ever formed.
Learn more about how Roman will study the cosmos in our other posts:
Telescopes located both on the ground and in space continue to dazzle us with incredible images of the universe. We owe these sharp vistas to a series of brilliant astronomers, including Andrea Ghez – an astrophysicist and professor at UCLA – and the “Mother of Hubble,” Nancy Grace Roman.
Did you know that stars don’t actually twinkle? They only look like they do because their light has to travel through our turbulent atmosphere to reach our eyes. As the atmosphere shifts and swirls around, the light from distant stars is slightly refracted, or bent, in different directions. Sometimes it’s directed right at us, but sometimes it’s directed a bit to the side.
It’s like someone’s shining a flashlight toward you but moving it around slightly. Sometimes the beam is pointed right at you and appears very bright, and sometimes it’s pointed a bit to either side of you and it appears dimmer. The amount of light isn’t really changing, but it looks like it is.
This effect creates a problem for ground-based telescopes. Instead of seeing sharp images, astronomers get fuzzy pictures. Special tech known as adaptive optics helps resolve pictures of space so astronomers can see things more clearly. It’s even useful for telescopes that are in space, above Earth’s atmosphere, because tiny imperfections in their optics can blur images, too.
In 2020, Andrea Ghez was awarded a share of the Nobel Prize in Physics for devising an experiment that proved there’s a supermassive black hole embedded in the heart of our galaxy – something Hubble has shown is true of almost every galaxy in the universe! She used the W. M. Keck Observatory’s adaptive optics to track stars orbiting the unseen black hole.
Roman’s Coronagraph Instrument will come equipped with deformable mirrors that will serve as a form of visual “autocorrect” by measuring and subtracting starlight in real time. The mirrors will bend and flex to help counteract effects like temperature changes, which can slightly alter the shape of the optics.
Other telescopes have taken pictures of enormous, young, bright planets orbiting far away from their host stars because they’re usually the easiest ones to see. Taking tech that’s worked well on ground-based telescopes to space will help Roman photograph dimmer, older, colder planets than any other observatory has been able to so far. The mission could even snap the first real photograph of a planet like Jupiter orbiting a Sun-like star!
Find out more about the Nancy Grace Roman Space Telescope on TwitterandFacebook, and learn about the person from which the mission draws its name.
Photographing Planets with the Roman Space Telescope
Nearly 100 years ago, astronomer Bernard Lyot invented the coronagraph – a device that made it possible to recreate a total solar eclipse by blocking the Sun’s light. That helped scientists study the Sun’s corona, which is the outermost part of our star’s atmosphere that’s usually hidden by bright light from its surface.
OurNancy Grace Roman Space Telescope, now under construction, will test out a much more advanced version of the same thing. Roman’s Coronagraph Instrument will use special masks to block the glare from host stars but allow the light from dimmer, orbiting planets to filter through. It will also have self-flexing mirrors that will measure and subtract starlight automatically.
This glare-blocking prowess is important because planets can be billions of times dimmer than their host stars! Roman’s high-tech shades will help us take pictures of planets we wouldn’t be able to photograph using any other current telescopes.
Other observatories mainly use this planet-hunting method, called direct imaging, from the ground to photograph huge, bright planets called “super-Jupiters” in infrared light. These worlds can be dozens of times more massive than Jupiter, and they’re so young that they glow brightly thanks to heat left over from their formation. That glow makes them detectable in infrared light.
Roman will take advanced planet-imaging tech to space to get even higher-quality pictures. And while it’s known for being an infrared telescope, Roman will actually photograph planets in visible light, like our eyes can see. That means it will be able to see smaller, older, colder worlds orbiting close to their host stars. Roman could even snap the first-ever image of a planet like Jupiter orbiting a star like our Sun.
Astronomers would ultimately like to take pictures of planets like Earth as part of the search for potentially habitable worlds. Roman’s direct imaging efforts will move us a giant leap in that direction!
