NASA astronaut Jessica Watkins is seen here floating above Earth in the International Space Station’s cupola, which provides a spectacular viewing spot for those who live and work on the space station.
The cupola is a dome-shaped module with six windows that face Earth. It was installed in 2010, and is a favorite spot for astronauts to do some Earth observation and quiet introspection. The small module is designed for the observation of operations outside the station such as robotic activities, the approach of vehicles, and spacewalks.
But the direct, nadir view of Earth through the windows is what astronauts enjoy the most. Those who have the incredible opportunity to see the Earth from space often report the view gives them a sense of awe, unity and clarity. This perspective-altering experience is known as the Overview Effect, from a book by the same name published 1987 by space philosopher Frank White.
Watkins is currently serving as a mission specialist on the ISS, and is part of the SpaceX Crew-4 mission, which launched on April 27, 2022. Watkins is the first Black woman to serve a long-duration mission on the space station.
The SpaceX Crew-4 astronauts (from left) with Mission Specialist Jessica Watkins, Pilot Robert Hines, Commander Kjell Lindgren, and Mission Specialist Samantha Cristoforetti. Credit: NASA.
“We have reached this milestone, this point in time, and the reason we’re able to arrive at this time is because of the legacy of those who have come before to allow for this moment,” Watkins said in an interview before launch. “Also, recognizing this is a step in the direction of a very exciting future. So to be a part of that is certainly an honor.”
Here are a few other great views of astronauts enjoying the cupola.
Astronaut Peggy Whitson spends time in the International Space Station’s Cupola during a 2017 tour of duty. Credit: NASA
Canadian Space Agency astronaut Chris Hadfield spends some quiet time to check out the view of Earth from the cupola of the International Space Station, while serenading his fellow astronauts. Credit: NASA
Astronaut Tracy Caldwell Dyson reflects on the view from the ISS’s Cupola.Credit: Doug Wheelock/NASA
This Planet is Way Too Big for its Star
Scientists love outliers. Outliers are nature’s way of telling us what its boundaries are and where its limits lie. Rather than being upset when an outlier disrupts their understanding, scientists feed on the curiosity that outliers inspire.
It’s true in the case of a new discovery of a massive planet orbiting a small star. That goes against our understanding of how planets form, meaning our planet-formation model needs an update.
In a paper published in Science, researchers announced the discovery of a Neptune-mass exoplanet orbiting a low-mass star. The star is LHS 3154, an M-dwarf, or red dwarf star. It’s only 0.11 times as massive as the Sun, which is a normal mass for a red dwarf.
But what’s surprising is the size of the planet orbiting the star. The planet is called LHS 3154b, and it’s a monster compared to most planets orbiting red dwarfs. It has at least 13.2 Earth masses. That places it in the same range as Neptune, which has 17 Earth masses. LHS 3154b is also in a very close orbit, taking only 3.7 days to orbit the star.
“This discovery really drives home the point of just how little we know about the universe.”
Suvrath Mahadevan, Penn State University
The new paper is “A Neptune-mass exoplanet in close orbit around a very low-mass star challenges formation models.” The lead author is Gudmundur Stefansson, NASA Sagan Fellow in Astrophysics at Princeton University. Stefansson was a graduate student at Penn State while working on this discovery.
“This discovery really drives home the point of just how little we know about the universe,” said Suvrath Mahadevan, a Professor of Astronomy and Astrophysics at Penn State and co-author of the paper. “We wouldn’t expect a planet this heavy around such a low-mass star to exist.”
Why is this discovery surprising? It’s all about stars and their protoplanetary disks.
When a star forms, it starts as a protostar in the center of a solar nebula. As the star forms, a rotating disk of gas and dust called a protoplanetary disk forms around the star. Dense knots form in the disk, and this is how planets and planetesimals form. It’s a detailed process and one we don’t entirely understand. But what scientists do know, or thought they knew, is that the more mass there is in the disk, the more massive the planets that can form. And the mass in the disk scales steeply with the mass of the star.
It looks like this: massive star = massive disk = massive planets. Naturally, we consider the obverse to be true, too. Small star = small disk = small planets. But LHS 3154b and its star don’t conform to this. There simply shouldn’t have been enough mass in the protoplanetary disk for the planet to form.
“The planet-forming disk around the low-mass star LHS 3154 is not expected to have enough solid mass to make this planet,” Mahadevan said. “But it’s out there, so now we need to reexamine our understanding of how planets and stars form.”
It took a special instrument to spot the massive planet, and Mahadevan led the team of scientists that built it. It’s called the Habitable Zone Planet Finder or HPF, a spectrograph built at Penn State. HPF is designed to detect planets orbiting cool stars that might have liquid surface water. Small planets can be very difficult to detect around large, bright stars like our Sun because the Sun’s light overpowers everything else.
But around smaller cooler stars, planets close enough to have liquid water are much easier to find.
“Think about it like the star is a campfire. The more the fire cools down, the closer you’ll need to get to that fire to stay warm,” Mahadevan said. “The same is true for planets. If the star is colder, then a planet will need to be closer to that star if it is going to be warm enough to contain liquid water. If a planet has a close enough orbit to its ultracool star, we can detect it by seeing a very subtle change in the colour of the star’s spectra or light as it is tugged on by an orbiting planet.”
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Will Wide Binaries Be the End of MOND?
It’s a fact that many of us have churned out during public engagement events; that at least 50% of all stars are part of binary star systems. Some of them are simply stunning to look at, others present headaches with complex orbits in multiple star systems. Now it seems wide binary stars are starting to shake the foundations of physics as they question the very theory of gravity.
General relativity has been part of the foundation of modern physics since it was published by Albert Einstein in 1915. One of the challenges though is that, along with normal matter (known by its official name baryonic matter) general relativity is unable to explain the current theories of the evolution of the universe without dark matter. Alas dark matter has not been observed in any lab experiment or indeed directly in the sky.
The idea for dark matter was developed in the early 1930’s to explain the movement of the galaxies in the Coma Cluster. It was Fritz Zwicky who coined the phrase dark matter in 1933 to explain the unseen matter that was driving the movement. Current theories suggest there is something like five times more dark matter in the Universe than there is normal matter but It’s a type of matter that we know little about other than it doesn’t interact with normal baryonic matter.
The Coma Galaxy Cluster. It appears to participate in the dark flow.
The standard model – that describes how the building blocks of matter interact – assumes that the current laws of gravity are all correct however a ‘tweak’ is required to explain certain observations and that tweak is called dark matter. In other words, we can see the effect of dark matter but we just haven’t actually directly detected it yet. In a paper published by J. W. Moffat, there is a bold suggestion that maybe it’s the gravitational model that is incorrect.
Enter MOND – ‘Modified Newtonian Dynamics’ – which proposes an adjustment to Newton’s second law (nicely encapsulated in the formula that force equals mass multiplied by acceleration) to explain the movement of galaxies without dark matter. The theory, proposed by M. Milgrom in 1983 suggests that the gravitational force exerted upon a star in the outer reaches of a galaxy was proportional to the square of its centripetal acceleration (instead of the centripetal acceleration itself). Remember the existing models do not explain this without inserting dark matter which we have yet to discover.
The paper by Moffat suggests that they should be able to detect the changes proposed by MOND but in applying the formulas correctly the galaxy constrains must be significantly affected. Wide binary data from Gaia (the Global Astrometric Interferometer) seems to conclude that any modified gravity theory must reliy upon scale and length rather than acceleration. If this continues to be the case for future observations then it may well mark the demise of the MOND model for good.
Source : Wide Binaries and Modified Gravity (MOG)
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Red Sprites are Best Seen from Space
Planet Earth is full of some truly awe-inspiring spectacles, but few are as intriguing as a sprite, which are officially known as a Transient Luminous Event (TLE) and consist of large-scale electric discharges that shoot upwards while occurring above the cloud tops in the Earth’s mesosphere at approximate altitudes of 50-90 km (31-56 mi). In October 2023, European Space Agency (ESA) astronaut, Dr. Andreas Mogensen, who is currently onboard the International Space Station (ISS) as Commander of the Expedition 70 mission, took an incredible image of a red sprite with the Davis camera as part of the Thor-Davis experiment and his Huginn mission.
Sprites have been observed from the ground and aircraft. However, the preferred observation method is from outer space due to the sprites occurring above the cloud tops and the low altitude of the ISS offering pristine views of these unique lightning features. While they are observed above cloud tops, they are hypothesized to originate from normal lightning near the Earth’s surface and act as a “balancing mechanism” used by the Earth’s atmosphere to distribute vertical electrical charges.
Since red sprites are essentially lightning strikes and visible for only a fraction of a second, specialized event-based cameras such as the Davis camera are required to precisely capture them. The Davis camera contrasts with a normal camera in that it does not take direct photographs, but instead creates images by sensing light and contract variances. Through this, the Davis camera capabilities are analogous to a normal camera taking 100,000 images per second.
Images of a red sprite taken by the Davis camera from the International Space Station in October 2023 by Expedition 70 Commander, Dr. Andreas Mogensen. (Credit: ESA/DTU/ A. Mogensen)
“These images taken by Andreas are fantastic,” said Dr. Olivier Chanrion, who is a senior researcher at Danish Technical University (DTU) Space and lead scientist for this experiment. “The Davis camera works well and gives us the high temporal resolution necessary to capture the quick processes in the lightning.”
The Thor-Davis experiment builds off the Thor experiment also conducted by Dr. Mogensen during his first mission to the ISS in 2015. During that experiment, Dr. Mogensen shot a 160-second video displaying 245 blue jets, which are another type of lightning event that shoots up towards space, with results from those findings being published in a 2016 study in Geophysical Research Letters.
The earliest recorded report of sprites—though they weren’t called that right away—occurred in November 1885 from the R.M.S. Moselle as it was leaving port in Jamacia with the sprites then being described as a “meteorological phenomenon” while “sometimes tinged with prismatic hues, while intermittently would shoot vertically upwards continuous darts of light displaying prismatic colours in which the contemporary tints, crimson and green, orange and blue, predominated.”
It took more than 100 years for the first photographic evidence of sprites to happen, when a team of scientists from the University of Minnesota accidentally imaged electrical discharges using a low-light-level television camera in 1989, with their findings later being published in Science the following year. It wasn’t until a 1995 study published in Geophysical Research Letters that these electrical charges were officially dubbed “sprites”. In the last several decades, sprites have been observed from all continents except for Antarctica, along with being observed from the ground, aircraft, and even outer space.
Image of red sprites taken in 2022 from the European Southern Observatory’s (ESO) La Silla Observatory in Chile. (Credit: Zdenek Bardon/ESO)
What new discoveries about sprites will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
The post Red Sprites are Best Seen from Space appeared first on Universe Today.
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