Space News & Blog Articles

Since the 1930s, physicists and radio engineer Karl Jansky reported discovering a persistent radio source coming from the center of our galaxy. This source came to be known as Sagittarius A* (Sgr A*), and by the 1970s, astronomers determined that it was a supermassive black hole (SMBH) roughly four million times the mass of our Sun. Since then, astronomers have used increasingly-advanced radio telescopes to study Sgr A* and its surrounding environment. This has led to many exotic discoveries, such as the many “Stars stars” and gaseous “G objects” that orbit it.

The study of these objects and how the powerful gravity of Sgr A* has allowed scientists to test the laws of physics under the most extreme conditions. In a recent study, an international team of researchers led by the University of Cologne made a startling discovery. Based on data collected by multiple observatories, they observed what appears to be a newly-formed star (X3a) in the vicinity of Sgr A*. This discovery raises significant questions about how young stellar objects (YSOs) can form and survive so close to an SMBH, where they should be torn apart by violent gravitational forces.

The research was led by Florian Peißker, a postdoctoral researcher at the University of Cologne’s Institute of Astrophysics. He was joined by colleagues from Masaryk University, the Institute for Astro and Particle Physics, JAXA’s Institute of Space and Astronautical Science (ISAS), the Astrophysics and Planetology Research Institute (IRAP), the Max Planck Institute for Radioastronomy (MPIA), the Czech Academy of Sciences Astronomical Institute, and the Observatoire de Paris. The paper that describes their findings, “X3: a high-mass Young Stellar Object close to the supermassive black hole Sgr A*,” recently appeared in The Astrophysical Journal.

This vicinity of Sgr A* is characterized by highly dynamic processes and hard radiation, the very conditions that act against star formation. As a result, astronomers have assumed for a long time that only older stars – which formed billions of years ago and settled into orbit via dynamical friction – would be found in the vicinity of SMBHs. However, astronomers have observed very young stars in the vicinity of Sgr A* for the past twenty years. This raised the obvious question of where and how they formed and found their way to their current orbits.

When observing X3a, the team noted that it was not only very young (several tens of thousands of years old) but also ten times the size and fifteen times as massive as the Sun. For their study, the team relied on data from multiple telescopes to conduct observations in multiple wavelengths. This consisted of near- and mid-infrared (NIR/MIR) measurements using the SINFONI, NACO, ISAAC, and VISIR instruments on the ESOs Very Large Telescope (VLT), the SHARP instrument on the New Technology Telescope (NTT), and the Near-Infrared Camera-2 (NIRC-2) on the W.M. Keck Telescopes.

The first written record of a supernova comes from Chinese astrologers in the year 185. Those records say a ‘guest star’ lit up the sky for about eight months. We now know that it was a supernova.

All that remains is a ring of debris named RCW 86, and astronomers working with the DECam (Dark Energy Camera) used it to examine the debris ring and the aftermath of the supernova.

Chinese astrologers recorded SN 185 in The Book of the Later Han, or as the Chinese call it, the Hou Han shu. There’s uncertainty around ancient records of astronomical events, and in the Hou Han shu’s case, the uncertainty is amplified by the fact that it was written 200 years after the events that transpired. Ancient Romans may have recorded the supernova explosion too, but that’s less certain.

Ancient records of celestial events can also be uncertain because of confusion between supernovae and comets. In the Hou Han shu, there’s no record of the guest star moving, and the location the Chinese recorded agrees with the position of RCW 86, the debris ring from the SN. Modern astronomers are pretty sure the Hou Han shu recorded SN 185, especially since modern high-tech observations help confirm it.

SN 185 exploded more than 8,000 light-years away in the rough direction of our nearest stellar neighbour Alpha Centauri. It’s a fascinating object because astronomers can observe the aftermath of a supernova explosion, one of nature’s most climactic events. RCW 86 is just a tattered remnant of SN 185 now, an increasingly misshapen ring of gas and dust. SN 185 was a Type 1a supernova, and unlike other types of supernovae, it left nothing behind other than the expanding, dissipating ring of debris.

At the center of the Milky Way, there is a massive persistent radio source known as Sagittarius A*. Since the 1970s, astronomers have known that this source is a supermassive black hole (SMBH) roughly 4 million times the mass of our Sun. Thanks to advancements in optics, spectrometers, and interferometry, astronomers have been able to peer into Galactic Center. In addition, thanks to the international consortium known as the Event Horizon Telescope (EHT), the world got to see the first image of Sagittarius A* (Sgr A*) in May 2022.

These efforts have allowed astronomers and astrophysicists to characterize the environment at the center of our galaxy and see how the laws of physics work under the most extreme conditions. For instance, scientists have been observing a mysterious elongated object around the Sgr A* (named X7) and wondered what it was. In a new study based on two decades’ worth of data, an international team of astronomers with the UCLA Galactic Center Group (GCG) and the Keck Observatory have proposed that it could be a debris cloud created by a stellar collision.

The research effort was led by the Galactic Center Initiative, an international project made up of scientists from the Mani L. Bhaumik Institute for Theoretical Physics, the University of California Los Angeles (UCLA), the W. M. Keck Observatory, the Observatoire de Paris (Sorbonne Universite), the University of California Berkeley, and the Instituto de Astrofísica de Andalucía (CSIS). The paper that describes their findings recently appeared in The Astrophysical Journal.

Using the Keck Observatory’s 10-meter (32.8 ft) Telescopes on Mauna Kea, the GCG team has been measuring the star closest to Sgr A* (S0-2) for more than twenty years (since 1995). They are one of only two groups in the world to have observed S0-2 make a full orbit of Sgr A* – a process that takes 16 years – for the sake of testing Einstein’s Theory of General Relativity. The team has spent that same time monitoring the object known as X7, a dust and gas cloud of about 50 Earth masses that takes 170 years to orbit the SMBH.

As they report in their study, X7 has become elongated and stretched by tidal forces as it has been pulled closer to Sag A*. Within the next few decades, they anticipate that X7 will disintegrate as the dust and gas that make it up are accreted onto the face of the SMBH. As Anna Ciurlo, a UCLA assistant researcher and the paper’s lead author, said in a UCLA press release:

A team of astronomers have proposed a series of missions utilizing land, sea, and airborne observatories to continuously monitor as many total solar eclipses as possible in the coming decade. These missions will reveal aspects of the solar corona that cannot be studied by any other means.

The space age brought a revolution in understanding the nature of the Sun. With the capability to place an observatory in orbit we could continuously monitor solar activity. The development of the coronagraph, which is a small disk placed in front of a telescope that blocks out the light from the surface of the Sun itself, also allowed observatories to study the corona. The corona of the Sun is the hot, thin atmosphere that extends out to twice the solar radius. 

The corona has a temperature of over a million degrees Kelvin, despite the surface of the Sun having a temperature of only around 10,000 Kelvin. Despite decades of intense research, we still do not fully understand how the corona reaches such incredibly high temperature, especially considering its low density and its distance from the Sun. Space-based observatories are able to map extensive regions of the corona, but they have difficulty observing continuous regions out past 50% greater than the Sun’s radius. Their limited field of view prevents them from having a complete picture.

The only way to develop a complete picture of the entire solar corona is to use a natural coronagraph, which happens with every total solar eclipse. During a total solar eclipse, the disk of the Moon blocks out that of the Sun, making the corona visible. Ground-based observatories have an advantage here over space-based ones because they can enjoy a much greater field of view.

The downside is that total solar eclipses do not last long and happen all over the globe. To counteract this, a team of astronomers have proposed a call for funding to support a series of total solar eclipse observations. They hope to use mobile ground-based observatories, observatories on ocean-going vessels, and telescopes in aircraft to capture as many coming total solar eclipses as possible.

Power infrastructure will be critical for any long-term space colony, and one of the most critical pieces of that power infrastructure, at least in the inner solar system, is solar cells. So in-situ research experts were thrilled when Blue Origin, ostensibly a rocket company, recently announced that they had made functional solar cells entirely out of nothing other than lunar regolith simulant. 

The process, which the aptly named Blue Alchemist, has been in the works for some time. According to a press release, Blue Origin has been working on making solar cells and necessary support components, such as wire and cover glass, all from regolith since 2021.

At its heart is a relatively simple process – molten regolith electrolysis. Basically, that means that blue origin uses electricity to split constituent atoms from the oxygen they are bound to in the lunar soil. Normal electrolytic cells separate water into hydrogen and oxygen, but Blue Alchemist takes the process a step further and separates elements such as iron, aluminum, and, most importantly, silicon from the oxygen they are bound to on the lunar surface.

One advantage of this process is that the “waste” product is oxygen – itself an invaluable material for lunar exploration, both as a component of breathable air, but also a potential rocket fuel. Silicon is the basis for not only solar cells but also glass, which needs to cover solar cells on the Moon to allow them to last more than a few days in the harsh radiative lunar environment. And iron and aluminum are useful for structural materials and conductive wire, in aluminum’s case. All this comes from the “dirt” that completely covers the surface of the Moon.

Blue Origin went so far as to make their own lunar regolith simulant to prove their process works rather than buying one already commercially available. They seemed to think that the commercially available simulants were too similar to a mish-mash of “lunar-relevant oxides” that didn’t truly represent the material found in the samples brought back by the Apollo mission and others.

The NASA/SpaceX Crew 6 members are now on their way to the International Space Stations after a spectacular nighttime liftoff from Launch Complex 39A at Kennedy Space Center.

At 12:34 am EST, a SpaceX Falcon 9 rocket sent a Dragon spacecraft named Endeavour into orbit. Onboard were NASA astronauts Stephen Bowen and Warren Hoburg, along with United Arab Emirates (UAE) astronaut Sultan Alneyadi and Roscosmos cosmonaut Andrey Fedyaev.

“Just want to say, as a rookie flyer, that was one heck of ride. Thank you!” Hoburg radioed back to Earth after Dragon successfully separated from the Falcon 9 rocket. “It’s an absolute miracle of engineering, and I just feel so lucky that I get to fly on this amazing machine.”

The crew is expected to dock to the ISS about 25 hours after the launch, at about 1:17 a.m., Friday, March 3, and have planned mission on the ISS for approximately 6 months.

Crew-6 will join Expedition 68, consisting of NASA astronauts Frank Rubio, Nicole Mann, and Josh Cassada, as well as JAXA (Japan Aerospace Exploration Agency) astronaut Koichi Wakata, and Roscosmos cosmonauts Sergey Prokopyev, Dmitri Petelin, and Anna Kikina. For a short time, the 11 crew members will live and work in space together until Crew-5 members Mann, Cassada, Wakata, and Kikina return to Earth a few days later.