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The ESA launched Gaia in 2013 with one overarching goal: to map more than one billion stars in the Milky Way. Its vast collection of data is frequently used in published research. Gaia is an ambitious mission, though it seldom makes headlines on its own.

But that could change.

Gaia relies on astrometry for much of its work, and astrometry is the measurement of the position, distance, and motions of stars. It’s so sensitive that it can sometimes detect the slight wobble a planet imparts to its much more massive star. Gaia detected its first two transiting exoplanets in 2021, and it’s expected to find thousands of Jupiter-size exoplanets beyond our Solar System.

But new research takes it even further. It shows that Gaia should be able to detect Earth-like planets up to 30 light-years away.

The new paper is “The Possibility of Detecting our Solar System Through Astrometry,” and is available on the pre-press site arxiv.org. It has a single author: Dong-Hong Wu from the Department of Physics, Anhui Normal University, Wuhu, Anhui, China.

Astronomers find most exoplanets with the transit method. A spacecraft like TESS monitors a section of the sky and looks at many stars at once. When a planet passes between us and one of the stars, it’s called a transit. It creates a dip in starlight that TESS’s sensitive instruments can detect. When TESS detects multiple, predictable dips, it signifies a planet.

But that’s not the only way to detect them. Astrometry can do it too, and that’s Gaia’s way.

Astrometry has an advantage over other methods. Gaia can more accurately determine an exoplanet’s orbital parameters. This doesn’t mean the other methods aren’t valuable. They obviously are. But as the paper’s author explains, “Neither the transit nor radial velocity method provides complete physical parameters of one planet, and both methods prefer to detect planets close to the central star. On the contrary, the astrometry method can provide a three-dimensional characterization of the orbit of one planet and has the advantage of detecting planets far away from the host star.” Astrometry’s advantages are clear.

If other technological planetary civs exist—and that’s a big if—then it’s not outrageous to think they have technology similar to Gaia’s. While Gaia is impressive, there are improvements on the horizon that will make astrometry even more precise. The author asks a question in his paper: If ETIs (ExtraTerrestrial Intelligences) are using advanced astrometry equal to or even surpassing Gaia’s, “…which of them could discover the planets in the solar system, even the Earth?”

Astrometrical precision is calculated in microarcseconds, and precision decreases with distance. The ESA says that Gaia can measure a star’s position within 24 microarcseconds for objects 4000 times fainter than the naked eye. That’s like measuring the thickness of a human hair from 1000 km away. But that’s not precise enough for Wu’s scenario. His work is based on even more advanced astrometry, the type we’ll likely have in the near future. “If the astrometry precision is equal to or better than ten microarcseconds, all 8,707 stars located within 30 pcs of our solar system possess the potential to detect the four giant planets within 100 years.”

This is the heart of Wu’s paper. The 30-parsec (approx. 100 light-years) region contains almost 9,000 stars, and if an ETI from one of those stars has powerful enough astrometry, then it could detect Jupiter, Saturn, Uranus, and Neptune. The only drawback is they’d have to observe our Solar System for nearly a century to make sure the signal was clear.

This figure from the research shows how long it would take for an ETI with advanced astrometry to detect our Solar System's four giant planets. 1,” the author writes. Image Credit: Wu 2023.” class=”wp-image-163369″ srcset=”https://www.universetoday.com/wp-content/uploads/2023/09/Giant-Planet-Detection.png 492w, https://www.universetoday.com/wp-content/uploads/2023/09/Giant-Planet-Detection-374×580.png 374w, https://www.universetoday.com/wp-content/uploads/2023/09/Giant-Planet-Detection-161×250.png 161w” sizes=”(max-width: 492px) 100vw, 492px” />
This figure from the research shows how long it would take for an ETI with advanced astrometry to detect our Solar System’s four giant planets. “We find that all the four giants in our solar system could be detected and well-characterized as long as they are observed for at least 90 years with SNR > 1,” the author writes. Image Credit: Wu 2023.

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Starship | Second Flight Test

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On November 18, 2023, Starship successfully lifted off at 7:02 a.m. CT from Starbase on its second integrated flight test.

While it didn’t happen in a lab or on a test stand, it was absolutely a test. What we did with this second flight will provide invaluable data to continue rapidly developing Starship.

The test achieved a number of major milestones, helping us improve Starship’s reliability as SpaceX seeks to make life multiplanetary. The team at Starbase is already working final preparations on the vehicles slated for use in Starship’s third flight test.

Congratulations to the entire SpaceX team on an exciting second flight test of Starship!

Follow us on X.com/SpaceX for continued updates on Starship’s progress

Did you miss our previous article…
https://mansbrand.com/for-its-final-trick-chandrayaan-3-brings-its-propulsion-module-to-earth-orbit/

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For its Final Trick, Chandrayaan-3 Brings its Propulsion Module to Earth Orbit

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On August 23, ISRO’s Vikram lander detached from its propulsion module and made a soft landing near the Moon’s south pole region. The lander then deployed its Pragyan rover, and for two weeks the endearing little solar-powered rover performed marvelously, detecting water ice and characterizing the makeup of the lunar regolith before succumbing to the darkness and cold of the lunar night.

But since the rover mission ended, the propulsion module that brought it to the Moon has made a detour, performing a series of complex maneuvers that took it from a tight lunar orbit back to Earth orbit. This was possible because the module still had more than 100 kg of fuel, allowing scientists to conduct additional maneuvers and experiments.

Right now, the propulsion module (PM) is orbiting Earth at an altitude of 115,000 km (71,500 miles), well above geostationary orbit. ISRO said the mission team decided to use the available fuel in the propulsion module to derive additional information for future lunar missions. More specifically, this demonstration gave them the chance to test mission operation strategies for a future sample return mission.

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A graphic of the Chandrayaan-3 lander separating from the propulsion module. Credit: ISRO.

The PM has had a busy and productive mission. While in lunar orbit for about a month, it wasn’t just taking it easy.  After the separation of the lander, the PM operated an on-board experiment, the Spectro-polarimetry of HAbitable Planet Earth (SHAPE) payload, designed to observe the Earth. Specifically, this instrument also provided scientists and engineers experience for future missions and research as its purpose was to study habitable planet-like features of Earth. These observations will be used by ISRO for future studies of exoplanets. Additionally, there was a special operation of the SHAPE payload on October 28, 2023 during the solar eclipse.

But because the spacecraft had such a precise orbit injection and optimal burn maneuvers, the amount of leftover fuel meant the engineers could do even more with the PM than originally expected. The PM was commanded to execute an orbit-raising maneuver at the Moon and then perform a Trans-Earth injection burn, which placed the PM in an Earth-bound orbit.

ISRO said the first orbit raising maneuver at the Moon was performed on October 9, 2023 to raise apolune altitude to 5,112 km from 150 km.  The Trans-Earth injection (TEI) maneuver was performed on October 13, 2023, and as its orbit was slowly raised, the PM made four Moon flybys before departing Moon on November 10.

Currently, propulsion module is orbiting Earth with an orbital period of nearly 13 days, at 27 degrees inclination. Because of this high orbit, ISRO said there is no threat of close approach with any operational Earth orbiting satellites.

ISRO said these extra operations allowed them to plan and execute trajectory maneuvers to return from Moon to Earth, as well as develop software to plan and validate the maneuvers. They also planned and executed a gravity assisted flyby between two celestial bodies and, most notably they avoided an uncontrolled crash into the Moon’s surface at the end of the life of PM, which met the requirements of creating no debris on the Moon.

Will its current high geostationary orbit be the Chandrayaan-3 PM’s final trick? Who knows? The resourceful engineers might figure out another way to make use of this multi-purpose spacecraft.

The post For its Final Trick, Chandrayaan-3 Brings its Propulsion Module to Earth Orbit appeared first on Universe Today.

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In 1872, a Solar Storm Hit the Earth Generating Auroras from the Tropics to the Poles

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Imagine a solar storm generating auroral displays across the entire sky. No, we haven’t quite seen them that strong in the current solar cycle. But, back in February 1872, people around the world reported seeing brilliant northern and southern lights. The culprit? A medium-sized sunspot group that unleased a torrent of charged particles in a coronal mass ejection directed toward Earth.

As with strong space weather storms today, the long-ago event not only sent aurorae dancing across most of Earth’s skies, but it disrupted technology. It affected telegraph communications on the submarine cable in the Indian Ocean between Bombay (Mumbai) and Aden for hours. Similar disturbances were reported on the landline between Cairo and Khartoum. That presaged the damage that such storms can do to today’s power grids and satellite communications.

Nowadays scientists know quite a bit more about the solar activity that causes these storms. Back in those days, however, solar science was still in its infancy. We didn’t have globe-girdling, interconnected communications systems. And, then as now, extremely strong solar storms were relatively rare, but they could still do damage. Today, we are well aware of the threat to modern technologies. Strong solar storms can shut down power stations, stop communications, threaten the world’s financial and trade systems, and harm life. “The longer the power supply could be cut off, the more society, especially those living in urban areas, will struggle to cope,” said Hisashi Hayakawa, the lead author of a group studying ancient solar storms. “Could we maintain our life without such infrastructure? Well, let us just say that it would be extremely challenging.”

Studying an Ancient Solar Storm

The 1872 solar event was named the Chapman-Silverman storm. Recently, an international team of 22 scientists, led by Hayakawa at Nagoya University in Japan, Edward Cliver at the US National Solar Observatory, and Frédéric Clette of the Royal Observatory of Belgium studied it in great detail. Their tools were historical records coupled with modern techniques to assess the Chapman-Silverman storm from its origins on the Sun to its impact on our planet.

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Sketches by Italian astronomer Angelo Secchi (Pontifical Gregorian University). The top shows the disk of the Sun, and the lower images show the 1872 sunspot group in more detail. Courtesy Osservatorio Astronomico di Roma.

How do you go about finding records for a storm that far back? First, you look at sunspot records. People have long sketched sunspot groups and records go back quite far. The team scoured Belgian and Italian records of sunspots during the period. For terrestrial impacts, they used geomagnetic field measurements recorded in places as diverse as Bombay (Mumbai), Tiflis (Tbilisi), and Greenwich. Those gave them insight into the temporal evolution and intensity of the storm. Finally, they examined hundreds of accounts of visual aurorae caused by the storm, written in different languages.

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A Japanese drawing of the aurorae triggered by the 1872 solar event. Courtesy Shounji Temple.

“Our findings confirm the Chapman-Silverman storm in February 1872 as one of the most extreme geomagnetic storms in recent history. Its size rivaled those of the Carrington storm in September 1859 and the NY Railroad storm in May 1921,” Hayakawa said. “This means that we now know that the world has seen at least three geomagnetic superstorms in the last two centuries.
Did you miss our previous article…
https://mansbrand.com/communicating-with-a-relativistic-spacecraft-gets-pretty-weird/

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