ESO’s Very Large Telescope (VLT) at Paranal Observatory, Chile, is the world’s most advanced optical instrument. The VLT uses state-of-the-art technology to provide the sharpest possible images, including adaptive optics with the laser guide stars shown in this image. The VLT uses these lasers to measure the turbulence in the Earth’s atmosphere, and responds by changing the shape of a mirror to counteract the negative effects of this turbulence.
This NASA/ESA Hubble Space Telescope image shows a cluster of hundreds of galaxies located about 7.5 billion light-years from Earth. The brightest galaxy within this cluster, named SDSS J1156+1911, is visible in the lower middle of the frame. It was discovered by the Sloan Giant Arcs Survey, which studied data maps covering huge parts of the sky from the Sloan Digital Sky Survey. The survey found more than 70 galaxies that look to be significantly affected by a cosmic phenomenon known as gravitational lensing.
Gravitational lensing is one of the predictions of Albert Einstein’s General Theory of Relativity. The mass contained within a galaxy is so immense that it can actually warp and bend the very fabric of its surroundings (known as space-time), forcing light to travel along curved paths. As a result, the image of a more distant galaxy appears distorted and amplified to an observer, as the light from it has been bent around the intervening galaxy. This effect can be very useful in astronomy, allowing astronomers to see galaxies that are either obscured or too distant to be otherwise detected by our current instruments.
Galaxy clusters are giant structures containing hundreds to thousands of galaxies, some with masses over one million billion times the mass of the Sun! SDSS J1156+1911 is only roughly 600 billion times the mass of the Sun, making it less massive than the average galaxy. However, it is massive enough to produce the fuzzy, greenish streak seen just below the brightest galaxy — the lensed image of a more distant galaxy.
Ryan Weed Positron Dynamics.
Current state of the art in-space propulsion systems based on chemical or ion propellants fail to meet requirements of 21st century space missions. Antimatter is a candidate mechanism for a propulsion system that could transport humans and/or robotic systems with drastically reduced transit times, providing quicker scientific results, increasing the payload mass to allow more capable instruments and larger crews, and reducing the overall mission cost. Unfortunately, previous propulsion concepts relied on unrealistic amounts of trapped antimatter — orders of magnitude away from any near-term capability. The goal of this effort is to determine the feasibility of a (TRL 1–2) radioisotope positron catalyzed fusion propulsion concept that does not rely on trapped antimatter. Such a transformative technology inspires and drives further innovation within the aerospace community and can be applied to a relevant mission — the bulk retrieval of an entire asteroid into translunar space — a mission of great scientific and commercial interest (e.g. asteroid mining). The idea of harnessing resources from asteroids goes back more than a century to Tsiolkovsky. Fundamentally, for asteroid mining to become financially viable, the cost of the retrieval spacecraft must be less than the value gained from the asteroid. Therefore, developing technology (e.g. efficient propulsion systems) that decreases the mass and complexity of the retrieval spacecraft must be a priority.
Editor: Loura Hall
In 2022, NASA’s Double Asteroid Redirection Test (DART) collides with the smaller body of the Didymos binary asteroid system in an attempt to measurably shift its orbit.
ESA’s Hera mission, now under study, will examine the aftermath of this impact to help determine whether humans can deflect threatening asteroids.
Hera will also demonstrate the ability to operate at close proximity around a low-gravity asteroid with some on-board autonomy similar in scope to a self-driving car, going on to deploy Europe’s first deep-space CubeSats, and potentially also a micro-lander, to test out a new multi-point intersatellite link technology.
In general, modelers attack the problem by breaking it into billions of bits, either by dividing space into a 3D grid of subvolumes or by parceling the mass of dark and ordinary matter into swarms of particles. The simulation then tracks the interactions among those elements while ticking through cosmic time in, say, million-year steps. The computations strain even the most powerful supercomputers. BlueTides, for example, runs on Blue Waters—a supercomputer at the University of Illinois in Urbana that can perform 13 quadrillion calculations per second. Merely loading the model consumes 90% of the computer’s available memory, Feng says.
For years such simulations produced galaxies that were too gassy, massive, and blobby. But computer power has increased, and, more important, models of the radiation-matter feedback have improved. Now, hydrodynamic simulations have begun to produce the right number of galaxies of the right masses and shapes—spiral disks, squat ellipticals, spherical dwarfs, and oddball irregulars—says Volker Springel, a cosmologist at the Heidelberg Institute for Theoretical Studies in Germany who worked on Millennium and leads the Illustris simulation. “Until recently, the simulation field struggled to make spiral galaxies,” he says. “It’s only in the last 5 years that we’ve shown that you can make them.”
The models now show that, like people, galaxies tend to go through distinct life stages, Hopkins says. When young, a galaxy roils with activity, as one merger after another stretches and contorts it, inducing spurts of star formation. After a few billion years, the galaxy tends to settle into a relatively placid and stable middle age. Later, it can even slip into senescence as it loses its gas and the ability make stars—a transition our Milky Way appears to be making now, Hopkins says. But the wild and violent turns of adolescence make the particular path of any galaxy hard to predict, he says.
By the end of 2022, China hopes to have its biggest space station yet orbiting around Earth, and the country’s space agency wants other nations to use it. China is inviting all members of the United Nations to submit applications to fly experiments on board the future habitat, dubbed the China Space Station. It’s a major step toward international cooperation for China and its space program, which has mostly relied on domestic hardware and capabilities in the past.
“The China Space Station belongs not only to China, but also to the world,” Shi Zhongjun, China’s ambassador to the UN, said in a statement about the initiative. As a guide for the decision, Zhongjun cited the 50-year-old Outer Space Treaty, which maintains that the exploration of space should be peaceful and benefit all countries.
Using a pioneering method, researchers from the Astronomy and Astrophysics Group of the UPC and the Canary Islands Institute of Astrophysics (IAC) have found a neutron star of about 2.3 solar masses—one of the most massive ever detected. The study was published on the 23rd of May in the Astrophysical Journal and opens a new path of knowledge in many fields of astrophysics and nuclear physics.
Neutron stars (often called pulsars) are stellar remnants that have reached the end of their evolutionary life: they result from the death of a star of between 10 and 30 solar masses. Despite their small size (about 20 kilometres in diameter), neutron stars have more mass than the sun, so they are extremely dense.
Researchers from the Universitat Politècnica de Catalunya (UPC) and the Canary Islands Institute of Astrophysics (IAC) used an innovative method to measure the mass of one of the heaviest neutron stars known to date. Discovered in 2011 and called PSR J2215+5135, with about 2.3 solar masses it is one of the most massive of the more than 2,000 neutron stars known to date. Although a study published in 2011 reported evidence of a neutron star with 2.4 solar masses, the most massive neutron stars that had previously achieved a consensus among scientists, reported in 2010 and 2013, have 2 solar masses.
Now that some time has passed since the release of Avengers: Infinity War, we should probably talk about Thanos, the nigh-omnipotent “Mad Titan” at the heart of Marvel’s latest blockbuster, and how he perfectly embodies one of the most pervasive societal misconceptions circling the topic of life extension. This might, therefore, be the first post here on LEAF that necessitates a spoiler warning, so here it is!
SPOILER ALERT — IF YOU CARE ABOUT HAVING INFINITY WAR, WHICH IS AN EXCELLENT MOVIE THAT YOU SHOULD SEE, SPOILED, PLEASE ABANDON SHIP AND HEREUPON RETURN AFTER WATCHING
Continue reading “Thanos, Overpopulation, and How to Save the Universe” »
LOS ANGELES – Deep thinkers have been saying for generations that we have to get off this rock and head for the stars, but the idea takes on a little more weight when the world’s richest person says it.
“We will have to leave this planet, and we’re going to leave it, and it’s going to make this planet better,” Jeff Bezos, the founder of Amazon retailing giant and the Blue Origin space venture, told me here on Friday night during a fireside chat at the National Space Society’s International Space Development Conference.
