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Astronomers have observed an accreting white dwarf abruptly lose and gain its brightness for the first time. White dwarfs are stars that have run out of their basic fuel: hydrogen. Usually, researchers have observed white dwarfs losing their brightness over days or months. Astronomers were studying the white dwarf binary system, TW Pictoris, and the white dwarf in it lost its brightness in 30 minutes, which surprised astronomers. Astronomers said it was accreting, or feeding on the energy from an orbiting companion star. To observe the unique phenomenon, astronomers used NASA’s Transiting Exoplanet Survey Satellite (TESS) that helps in planet-hunting processes.

The brightness of a white dwarf is not dependent on its own hydrogen source, as it has already exhausted it. Its brightness depends on the amount of surrounding material that it feeds on. The abrupt switching on and off of the white dwarf may be due to some interference with food supply, said researchers.

The research was led by England’s Durham University. The findings were published on October 18, 2021, in the Nature Astronomy journal.

TW Pictoris comprises a white dwarf and a smaller companion star. The white dwarf feeds from the accretion disc that is fuelled by hydrogen and helium from the companion star. The more energy it feeds on, the brighter it becomes.

Researchers noticed the abrupt rise and fall in the brightness of this white dwarf, the likes of which they had never seen before. They believe this could be caused by reconfiguration of the white dwarf’s surface magnetic field.

At its brightest phase, the white dwarf feeds off the accretion disc. But suddenly the magnetic field starts spinning so rapidly that a centrifugal barrier is created. This stops the fuel from the accretion disc to reach the white dwarf.

The “magnetic gating” regulates the fuel passing from the disc to the white dwarf. Due to the small amount of fuel passing through the “gate” the white dwarf experiences semi-regular small increases in brightness.

Then, the system switches “on” again, allowing the white dwarf to feed normally from the disc. The brightness reaches its peak again.

Lead author Dr. Simone Scaringi said, “This really is a previously unrecognised phenomenon and because we can draw comparisons with similar behaviour in the much smaller neutron stars it could be an important step in helping us to better understand the process of how other accreting objects feed on the material that surrounds them and the important role of magnetic fields in this process.”

This extraordinary observation could lead to further studies of white dwarfs and neutron stars.


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Smithsonian Air and Space Museum Reopens with SpaceX Rocket, Mars Habitat and More

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Smithsonian Air and Space Museum Reopens with SpaceX Rocket, Mars Habitat and More

Hundreds waited at the ready outside the Smithsonian’s National Air and Space Museum on Monday (July 28), when “the doors opened for access to five featured and newly renovated galleries that capture the history, contemporary status, and futuristic vision of aviation and space exploration. These refurbished spaces showcase a mix of historic and high-tech artifacts such as John Glenn’s “Friendship 7” capsule, pieces of a SpaceX Falcon 9 rocket, and a 3D-printed Mars habitat. Visitors were among the first to experience a sweeping display of innovation, housed within the museum’s revitalised main building on the National Mall in Washington, D.C.

Smithsonian’s $900M Overhaul Brings Futuristic Space Exhibits and Aviation History to Life

As per a Smithsonian statement, the reimagined exhibits are part of a $900 million full-building transformation launched in 2018, scheduled for completion by July 2026—the museum’s 50th anniversary. This phase marks the second group of reopened galleries since the start of 2022. After a three-year closure, the north entrance opened for the first time, leading visitors through a newly wing-shaped vestibule and into “Boeing Milestones of Flight Hall”, now with improved lighting, digital screens, and iconic artefacts.

Next to it, a new “Futures in Space” gallery showcases domestic exhibitions from private space companies like SpaceX, Blue Origin, Virgin Galactic, and Axiom Space. Rather than a chronological or program-based layout, the gallery explores philosophical and practical questions about space: Who decides who goes? Why do we venture out? What will we do once we arrive? The immersive layout blends historical items, contemporary designs, and even pop culture references.

The museum has reopened galleries such as “Barron Hilton Pioneers of Flight”, “World War I: The Birth of Military Aviation”, and “Allan and Shelley Holt Innovations Gallery”, and the upgraded Lockheed Martin IMAX Theatre, praised as educational and inspirational.

Despite free entry, the Smithsonian Museum reopened to more than 6,000 guests, who must pick up timed-entry passes in order to better manage crowd flow.

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NASA’s Solar Observatory Sees Two Eclipses in One Day

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NASA’s Solar Observatory Sees Two Eclipses in One Day

NASA’s Solar Dynamics Observatory (SDO) has witnessed and recorded an unprecedented phenomenon of two solar eclipses in one day on July 25, 2025. These two eclipses took place only hours apart that day, and were photographed by SDO instruments pointed up and away from the Sun in geosynchronous orbit. First, around 2:45 UTC, the Moon passed between SDO and the Sun. Then, starting at about 6:30 UTC, Earth itself eclipsed the Sun from SDO’s point of view, with the Sun disappearing behind our planet shortly before 8:00 UTC. Since launching in 2010, SDO has continuously monitored the Sun’s activity, from solar flares to magnetic fields, helping forecasters predict space weather.

Moon Transit

According to NASA, SDO orbits Earth in a high geosynchronous orbit, so it has an almost constant view of the Sun. On July 25, this vantage point captured a partial solar eclipse as the Moon passed between the spacecraft and the Sun. NASA’s mission team had predicted this “lunar transit” would cover about 62% of the solar disk. Indeed, the Moon’s silhouette moved slowly across the Sun (around 2:45–3:35 UTC), blocking roughly two-thirds of the bright disk at maximum. The observatory’s ultraviolet telescope (AIA) recorded the event, revealing the Sun’s lower atmosphere and coronal loops around the sharply defined lunar edge. This transit was the deepest lunar eclipse SDO saw in 2025.

Earth’s Eclipse from Space

Hours later, on the same day, Earth itself passed between SDO and the Sun. Beginning around 6:30 UTC on July 25, our planet fully blocked the observatory’s view of the solar disk. This occurred during SDO’s regular eclipse season (a roughly three-week period twice each year when Earth’s orbit crosses the satellite’s line of sight). The total eclipse lasted until shortly before 8:00 UTC. In SDO’s images, Earth’s shadow has a fuzzy edge because our atmosphere scatters sunlight, in contrast to the Moon’s crisp eclipse.

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NISAR Launches July 30: A NASA-ISRO Satellite to Track Earth’s Changes

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NISAR Launches July 30: A NASA-ISRO Satellite to Track Earth’s Changes

The NASA-ISRO Synthetic Aperture Radar (NISAR) satellite, a joint Earth science mission, is now set for launch from India’s Satish Dhawan Space Centre. The pickup-truck-sized spacecraft was encapsulated in the nose cone of an Indian Geosynchronous Satellite Launch Vehicle and is scheduled to lift off on Wednesday, July 30 at 8:10 a.m. EDT (5:40 p.m. IST). Once in orbit, its dual-frequency radars will circle Earth 14 times a day, scanning nearly all of the planet’s land and ice surfaces every 12 days. It will provide data to help scientists monitor soil moisture and vegetation, and better assess hazards like landslides and floods.

International Collaboration and Launch Readiness

According to the official website, NISAR reflects a significant NASA–ISRO partnership. NASA’s Jet Propulsion Laboratory (JPL) built the long-wavelength L-band radar, and India’s Space Applications Centre built the shorter-wavelength S-band radar. This dual-frequency design makes NISAR the first Earth satellite to carry two radar systems, underscoring the mission’s unique collaboration.

The spacecraft is now integrated into its launch vehicle at India’s Satish Dhawan Space Centre. On July 28 NASA announced NISAR had been encapsulated in the payload fairing of an ISRO Geosynchronous Satellite Launch Vehicle on the pad. The GSLV is scheduled to lift off at 8:10 a.m. EDT (5:40 p.m. IST) on Wednesday, July 30.

Advanced Dual-Frequency Radar

NISAR carries a novel dual-frequency radar system. The satellite’s instruments operate at L-band (25 cm) and S-band (10 cm) wavelengths. The longer L-band waves can penetrate forests and soil to sense moisture and land motion, while the shorter S-band waves pick up fine surface details like vegetation moisture and roughness. This combination lets NISAR detect both large-scale and fine-scale changes.

From orbit, NISAR will circle Earth 14 times per day, scanning nearly all land and ice surfaces twice every 12 days. Its data will track changes like the advance or retreat of polar ice sheets and slow ground shifts from earthquakes, and will also aid agriculture and disaster planning by helping monitor crops and prepare for floods and hurricanes.

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