Slowly but surely, the 18 hexagonal segments that make up the James Webb Space Telescope’s 6.5-meter (21.3-foot) segmented main mirror are aligned to bring starlight to razor-sharp clarity.

After Webb arrived in space on Christmas Day, the segments were only roughly aligned. But using the observatory’s near-infrared camera, NIRCam, scientists and engineers map this alignment and gradually adjust the orientation of each segment using actuators on the back of each.

First, the team pointed Webb at a star in Ursa Major and adjusted the segments so that the light reflected from each reflected their physical positions. Then, further adjustments brought each reflection into focus in a process known as segment alignment:

Now all the segments have been oriented so that the reflections are “stacked” or merged into a single beam. Although the image stacking process puts all the light from the segments in the same place inside NIRCam, further adjustments are needed to ensure that all 18 combine to form a single 6.5 meter mirror.

In the fourth phase of segment alignment, known as “coarse phasing”, spectra will be collected from 20 distinct segment pairings, showing minute height differences between each. As these differences are adjusted, the single stacked image will become progressively sharper.

“We still have work to do, but we’re increasingly pleased with the results we’re seeing,” said Lee Feinberg, head of optical telescope elements for Webb at NASA’s Goddard Space Flight Center. “Years of planning and testing are paying dividends, and the team couldn’t be more excited to see what the next few weeks and months bring.”

By ESA/Hubble
February 27, 2022

Over the past 30 years, the Hubble Space Telescope has helped transform our understanding of the universe. And all the while, it has also regularly quenched the public’s thirst for breathtaking views of nebulae and galaxies dotted across the cosmos.

Known as Arp 282 and located some 300 million light-years away, the galactic duo pictured above, and captured by Hubble, reveals galaxy NGC 169 (bottom) visibly interacting with galaxy IC 1559 ( at the top). In the photo, you can see streaks of gas and dust delicately connecting the two galaxies, the result of the immense tidal forces involved when two gravitational goliaths stray too close.

Although galaxies can often seem isolated, with no close neighbors in sight, that doesn’t mean they always will be. And thanks in part to Hubble images like this, astronomers now know that gaze interactions and head-on collisions between galaxies are fairly common (even though such collisions rarely result in individual star collisions). In fact, close encounters like this play a fundamental role in changing the size, shape, and structure of galaxies over billions of years. Moreover, when two galaxies interact, it can even stir up the gas and dust they contain, triggering new bursts of star formation.

So while galactic collisions, at first glance, may seem like cosmic calamities, in the long run they could actually breathe new life into otherwise darkened and dying island universes.

To discover such an invisible black hole, the team of scientists had to combine two different types of observations over several years.

The campaign was well underway when Bridges and Mandel joined. They found the lab when they were undergraduates, but their interest in astronomy was sparked much earlier. In elementary school, Bridges remembers bringing a stack of photos taken from the Mars Rover to show and tell. For Mandel, it was the recycled rockets SpaceX sent into space and then recovered that blew her away. The mentorship and hands-on experience they received convinced them to stay for their PhD. Colombia News spoke with Bridges and Mandel about studying Jupiter and the advice they have for other astronomy enthusiasts.

Q. What causes auroras?

Gabriel Bridges: Occur when charged particles from space strike a planet’s magnetic field and are deflected toward the planet’s north and south poles. The magnetic field attracts the particles, and when they crash into the atmosphere, they slow down considerably and emit a lot of electromagnetic radiation. On Earth, most radiation is visible light. If you are far enough north (or south), you will see brilliant green curtains of light that are the result of electrons colliding with oxygen atoms in our atmosphere.

Shifra Mandel: The magnetic field that connects the north and south poles of the Earth forms a protective barrier that prevents the solar wind from eroding our atmosphere; it also protects life from potentially harmful cosmic rays. The magnetosphere is constantly bombarded with charged particles; some penetrate the outer layers and are accelerated along the magnetic field lines towards the two poles. When these energetic particles collide with the Earth’s atmosphere, they generate auroras.

Q. What do the auroras look like from Jupiter?

GB: Interestingly, Jupiter’s aurora borealis is quite unimpressive, at least to the human eye. The real light show occurs at higher energies than what we can see. Jupiter’s ultraviolet auroras are bright, lingering features that can be seen in this visualization based on data from NASA’s Hubble Space Telescope. In this video, you can clearly see the magnetic fingerprint of Jupiter’s moon, Io. This luminous point at the bottom right of the aurora is the magnetic shadow of Io.

SM: Io is constantly bombarding Jupiter with charged particles from volcanic eruptions on its surface. These charged particles are the source of most of the X-ray emissions we see. In contrast, Earth’s main source of ions comes from periodic solar storms. Thus, our aurora borealis are not continuous like those of Jupiter.

Q. What’s so intriguing about Jupiter’s X-ray light?

GB: Jupiter’s magnetic field is 20 times stronger than Earth’s and the strongest in our solar system. If Jupiter’s magnetic field were visible at its widest point from Earth, it would appear three times larger than our sun or moon. This means that Jupiter has unparalleled power to accelerate and focus charged particles. Thus, you would expect more energetic X-rays from Jupiter than from Earth because its magnetic field generates such a large energetic acceleration.

Jupiter’s closest moon also emits a ton of ions and electrons every second. This gives Jupiter a constant supply of charged particles to power its auroras. Back on Earth, we have to wait for solar storms to pull charged particles into our atmosphere.

SM: If we were standing on Jupiter to observe Earth, we probably wouldn’t be able to see the Earth’s aurora borealis. But Jupiter’s auroras are so much more powerful that we can observe them from the same distance.

Q. What other planets in our solar system emit high energy radiation?

GB: The planets emit high-energy radiation through the auroras and by reflecting the X-rays emitted by the sun. To produce an aurora, three things are needed: a magnetic field, an atmosphere and a source of charged particles. Most planets in our solar system do not meet these criteria. Mercury has no atmosphere. Mars and Venus do not have a magnetic field. Uranus and Neptune have weak magnetic fields. That leaves Earth, Jupiter, and Saturn. We know Earth and Jupiter certainly have X-ray auroras, but we’re not sure about Saturn yet!

Q. What is the mystery at the heart of this article?

SM: The space probe Ulysses flew over Jupiter in 1992 equipped with a detector to record high-energy X-rays between 27 and 48 kiloelectronvolts (keV) but found nothing. This intrigued astrophysicists, who expected that electrons producing ultraviolet radiation from Jupiter’s auroras would also produce energetic X-rays. The mystery deepened when the European Space Agency’s XMM-Newton telescope later recorded high-energy X-rays near the upper end of its detection limit, around 7 keV. The source of this X-ray emission was unclear, but we were confident that NuSTAR, with its ability to detect radiation from 3 keV to 79 keV, could provide answers.

Q. How did you solve it?

SM: NuSTAR observations have confirmed that Jupiter produces X-rays as high as 20 keV – much higher than what XMM-Newton is able to detect, but below the detection band of Ulysses, which is why Ulysses missed it. To test our suspicions that the X-rays detected by NuSTAR were generated by electrons flowing through Jupiter’s atmosphere, we examined data from NASA’s Juno space probe; as Juno orbits Jupiter, it records the levels of charged particles in its path. We simulated the effects of these particles passing through and colliding with a Jupiter-like atmosphere. We found that the x-rays produced matched the radiation we saw with the NuSTAR telescope.

Q. What should everyone know about astrophysics?

GB: It’s not as pretentious and inaccessible as it may seem. Everyone can have an impact. All it takes is a lot of time and hard work. If you are interested, find a researcher and ask to work with him.

SM: It’s not easy, but if you like it, it’s really worth it!

Q. Any advice for other students debating a career in astronomy?

GB: I used to think that I couldn’t contribute to a research group until I knew X, Y and Z in physics. If you’re seriously interested, the best time to start researching is now. The second best time is tomorrow! You won’t know what a career in astrophysics is like until you try.

SM: Find your niche: something you’re passionate about, something that makes you want to get out of bed in the morning.

Title: STRIDES: a 3.9% measurement of the Hubble constant from the strong lens system DES J0408−5354

Authors: Anwar. J. Shajib, Simon Birrer, Tommaso Treu, et al.

Institution of the first author: Department of Physics and Astronomy, University of California, Los Angeles

Status: Posted in MNRAS [open access]

The Universe is growing. But how big is it now and how fast is it growing? Much like how pediatricians use our heights as children to predict our future heights and growth rates, astronomers can measure the rate of expansion of the Universe, also known as the Hubble constant (H₀), modeling light from when the Universe was just a baby. More precisely, observations of the cosmic microwave background, the light emitted when the Universe was only 400,000 years old, give a Hubble constant of about 67 km/s/Mpc (the universe has about 14 billion years now).

But wait! The doctor across town just called. She measured a Hubble constant of 73 km/s/Mpc using a completely independent method that uses nearby stars called Cepheids. The debate over conflicting values ​​of H₀ is known in astronomy as the “Hubble tension” (see this astrobite for a full review).

It’s crucial that astronomers get to the bottom of this discrepancy, because the Hubble constant has a huge impact on our current understanding of cosmology. For example, the Hubble constant constrains dark energy patterns and neutrino masses, which are extremely low-mass particles with zero charge. One solution to the tension is to measure the Hubble constant with as many different methods as possible, so we can determine which models are incorrect. Today’s article focuses on one such technique which capitalizes on a new method involving gravitational lensing.

Using curved light to measure the Universe

Gravitational lensing occurs when light rays from a distant source are bent around a nearby massive object due to its gravitational field. The light rays from the source can end up taking different paths due to the mass occurring along the line of sight and the expansion of the universe. So for us as observers, the result is the appearance of multiple images! A cartoon of how light from a variable source is bent around a galaxy, and then appears to us as four images on Earth, is shown in Figure 1. If the source is variable, such as a quasar (extremely bright objects fed by supermassive black light holes), then the different images from the same source appear not only in different places, but also at different times, offset from each other due to the different paths taken by light (hence “time delay”). Cosmologists have found a trick: the delay is proportional to the Hubble constant and can be used to deduce it. This method of inference to measure H₀ is called delayed cosmographywhich is a fancy phrase for using measured time frames to probe the size and characteristics of the universe.

DES J0408-5354: the first multi-source system used to measure H₀

This paper uses Hubble Space Telescope (HST) imagery of a strong lens system, DES J0408-5354, shown in Figure 2. This lens system is unique in that it has multiple sources (i.e., say the quasar (ABCD images, S2 and S3 in Figure 2), where previously studied lens systems contained only a single light source. . This article also addresses one of the main problems currently facing time-lapse cosmography: the modeling of the mass distribution effecting the lensing, on which the value of the Hubble constant strongly depends. The fact that this lens system has multiple sources makes it even more difficult to model, which is why the success of this article has been so groundbreaking. To also help avoid bias affecting the modeling, the authors use a technique called blind analysis, where the authors avoided looking at the results until the end.

The authors end up measuring a constant Hubble value of H₀ = 74.2 km/s/Mpc, with an uncertainty of 3.9%, shown in Figure 3. This number is currently consistent with measurements of Cepheid stars, but the authors hope to eventually achieve 1% uncertainty with software improved modeling and more lens systems. In the modern era of precision cosmology, we are getting a clearer picture of what our universe will look like when it grows.

Astrobite edited by Evan Lewis and Wynn Jacobson-Galan

Featured image credit: Amazon

About Abby Lee

I am a graduate student at UChicago, where I study Cosmic Distance Scales and Hubble Voltage. Apart from astronomy, I like to play football, run and learn fashion design!

NASA took to their blog to explain that the Hubble Space Telescope was used to observe a region of space called the Chamaeleon Cloud Complex.

SEE THE GALLERY – 2 IMAGES

The Chamaeleon Cloud Complex is a star forming region that spans 65 light years across. The photograph above is a composite image called Chamaeleon Cloud I (Cha I), and it features the reflection nebulae shining with the light of young blue stars. Additionally, the dark, dusty clouds seen in the image are regions of space where stars are forming. Radiating nodes are also visible throughout the image. These are called Herbig-Haro objects.

NASA explains:Herbig-Haro objects are bright tufts and arcs of interstellar gas shocked and energized by jets expelled from infant “protostars” in the process of formation. The white-orange cloud at the bottom of the image hosts one of these protostars at its center. Its bright white jets of hot gas are ejected in narrow torrents from the poles of the protostar, creating Herbig-Haro object HH ​​909A.“

The space agency writes that Cha 1 was observed with the intention of locating low-mass brown dwarf stars. NASA describes these stars as “lack“due to their lack of mass preventing them from igniting to maintain nuclear fusion in their cores.”Hubble research has found six new low-mass brown dwarf candidates that help astronomers better understand these objects.“

For more information on this story, see this link here.

Jak Connor

Jak joined the TweakTown team in 2017 and has since reviewed hundreds of new tech products and kept us up to date with the latest science and space news daily. Jak’s love of science, space and technology, and specifically PC gaming, began when he was 10 years old. It was the day his father showed him how to play Age of Empires on an old Compaq PC. From that day on, Jak fell in love with games and the advancement of the tech industry in all its forms. Instead of a typical FPS, Jak holds a very special place in his heart for RTS games.

About 13.8 billion years ago, our Universe was born from a massive explosion that gave rise to the first subatomic particles and the laws of physics as we know them. About 370,000 years later hydrogen had formed, the building block of stars, which fuse the hydrogen and helium within them to create all of the heavier elements. Although hydrogen remains the most common element in the Universe, it can be difficult to detect individual clouds of hydrogen gas in the interstellar medium (ISM).

This makes it difficult to find the earliest phases of star formation, which would offer clues to the evolution of galaxies and the cosmos. An international team led by astronomers from the Max Planck Institute for Astronomy (MPIA) recently noticed a massive filament of atomic hydrogen gas in our galaxy. This structure, named “Maggie”, is located about 55,000 light-years away (on the other side of the Milky Way) and is one of the longest structures ever observed in our galaxy.

The study that describes their findings, recently published in the journal Astronomy & Astrophysics, was led by Jonas Syed, a Ph.D. student at the MPIA. He was joined by researchers from the University of Vienna, the Harvard-Smithsonian Center for Astrophysics (CFA), Max Planck Institute for Radio Astronomy (MPIFR), University of Calgary, Universität Heidelberg, Center for Astrophysics and Planetary Science, Argelander-Institute for Astronomy, Indian Institute of Science, and Nasa‘s Jet Propulsion Laboratory (JPL).

The research is based on data obtained from the Milky Way HI/OH/Recombination Line Study (THOR), an observing program that relies on the Karl G. Jansky Very Large Array (VLA) at the New Mexico. Using the VLA’s centimetre-wave radio dishes, this project studies molecular cloud formation, the conversion of atomic hydrogen to molecular hydrogen, the magnetic field of the galaxy, and other questions related to ISM and to star formation.

The ultimate goal is to determine how the two most common hydrogen isotopes converge to create dense clouds that rise to new stars. Isotopes include atomic hydrogen (H), consisting of one proton, one electron, and no neutrons, and molecular hydrogen (H₂) is composed of two hydrogen atoms linked by a covalent bond. Only the latter condenses into relatively compact clouds that will develop frosty regions where new stars eventually emerge.

This image shows a section of the side view of the Milky Way as measured by ESA’s Gaia satellite. The dark band is made up of gas and dust, which attenuates the light from the embedded stars. The galactic center of the Milky Way is shown on the right of the image, glowing below the dark area. The box to the left of the middle marks the location of the “Maggie” filament. It shows the distribution of atomic hydrogen. The colors indicate different gas velocities. Credit: ESA/Gaia/DPAC, CC BY-SA 3.0 IGO & T. Müller/J. Syed/MPIA

The transition process from atomic hydrogen to molecular hydrogen is still largely unknown, which made this extraordinarily long filament a particularly exciting discovery. While the largest known clouds of molecular gas are typically around 800 light-years in length, Maggie is 3,900 light-years long and 130 light-years wide. As Syed explained in a recent MPIA press release:

“The location of this filament contributed to this success. We don’t yet know exactly how it got there. But the filament extends about 1600 light-years below the plane of the Milky Way. The observations also allowed us to determine the velocity of hydrogen gas. This allowed us to show that the velocities along the filament hardly differ.”

The team’s analysis showed that the material in the filament had an average speed of 54 km/s^-1, which they determined primarily by measuring it relative to the rotation of the Milky Way’s disk. This meant that radiation at a wavelength of 21 cm (aka the “hydrogen line”) was visible against the cosmic background, making the structure discernible. “The observations also allowed us to determine the velocity of hydrogen gas,” said Henrik Beuther, director of THOR and co-author of the study. “This allowed us to show that the velocities along the filament hardly differ.”

This false color image shows the distribution of atomic hydrogen measured at a wavelength of 21 cm. The red dotted line traces the “Maggie” filament. Credit: J. Syed/MPIA

From there, the researchers concluded that Maggie is a coherent structure. These findings confirmed observations made a year earlier by Juan D. Soler, an astrophysicist at the University of Vienna and co-author of the paper. When he observed the filament, he gave it the name of the longest river in his native Colombia: the Río Magdalena (anglicized: Margaret, or “Maggie”). While Maggie was recognizable in Soler’s earlier assessment of THOR data, only the current study proves beyond doubt that it is a consistent structure.

Based on previously published data, the team also estimated that Maggie contains 8% molecular hydrogen by mass fraction. Upon closer inspection, the team noticed that the gas converges at various points along the filament, leading them to conclude that the hydrogen gas collects in large clouds at these locations. They further speculate that atomic gas will gradually condense into a molecular form in these environments.

“However, many questions remain unanswered,” Syed added. “Additional data, which we hope will give us more clues about the molecular gas fraction, is already waiting to be analyzed.” Fortunately, several space and ground observatories will soon be operational, telescopes that will be equipped to study these filaments in the future. These include the James Webb Space Telescope (JWST) and radio soundings like the Square Kilometer Array (SKA), which will allow us to visualize the very first period of the Universe (“Cosmic Dawn”) and the first stars of our Universe.

Originally published on Universe Today.

For more on this research, see Massive Filament Structure – 3900 Light-Years Long – Discovered in the Milky Way.

Reference: “The “Maggie” filament: physical properties of a giant atomic cloud” by J. Syed, JD Soler, H. Beuther, Y. Wang, S. Suri, JD Henshaw, M. Riener, S. Bialy, S 20 December 2021, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202141265

As stars begin to reach the end of their life cycle, they get bigger. Surrounding planets lose their orbital energy and move closer together, eventually being consumed by the star.

The Earth will eventually be swallowed up by the Sun, but that won’t happen for at least five billion years. The Sun is estimated to be about halfway through its life cycle.

Astronomers at the University of Hawaii have discovered three planets about to be absorbed by stars similar in mass to our Sun. They were detected using NASA’s Transiting Exoplanet Survey Satellite (TESS) space telescope.

“The changes we expect to see for the Sun are the same as we see in these different solar systems where the radius of the star increases, the star swells and cools, but the radius will increase so dramatically that we we expect the inner planets of the solar system to actually be consumed by the surface of the Sun itself,” said Nick Saunders, a UH graduate student working on the project.

“So as the radius of the Sun moves away, the inner planets out to the vicinity of Earth will likely be inside the star at that time,” Saunders said.

The three observed planets (TOI-2337b, TOI-4329b, TOI-2669b) are less than 2,000 light-years from Earth.

The planet labeled TOI-2337b will be swallowed up by its star in less than a million years. Of all the currently observable planets, this one will be consumed by a star the earliest.

A group of astronomers and citizen scientists have discovered a hidden planet the size of Jupiter in a distant solar system, and they should be lucky enough to see it again soon.

The planet, designated TOI-2180 b, is relatively close to us here on Earth, just 379 light-years away. But what makes this world special among the sample of known giant exoplanets is that it takes 261 days to orbit its host star, far longer than most gas giants discovered outside our solar neighborhood. .