From EsoCast. Planet hunters unveil the tricks of the trade for finding planets around nearby stars and scanning them for signs of life.
Are we alone? It’s the biggest question ever. And the answer is almost within reach. With so many galaxies, and each with so many stars, how could the Earth be unique?
In 1995, Swiss astronomers Michel Mayor and Didier Queloz were the first to discover an exoplanet orbiting a normal star. Since then, planet hunters have found many hundreds of alien worlds. Large and small, hot and cold, and in a wide variety of orbits. Now, we’re on the brink of discovering Earth’s twin sisters. And in the future: a planet with life — the Holy Grail of astrobiologists.
Michel Mayor’s team found hundreds of them from Cerro La Silla, ESO’s first Chilean foothold. Here’s the CORALIE spectrograph, mounted on the Swiss Leonhard Euler Telescope. It measures the tiny wobbles of stars, caused by the gravity of orbiting planets.
ESO’s venerable 3.6-metre telescope is also hunting for exoplanets. The HARPS spectrograph is the most accurate in the world. So far, it has discovered more than 150 planets. Its biggest trophy: a rich system containing at least five and Continue reading Finding Another Earth Within Reach→
The universe has long captivated us with its immense scales of distance and time. How far does it stretch? Where does it end, and what lies beyond its star fields and streams of galaxies extending as far as telescopes can see?
These questions are beginning to yield to a series of extraordinary new lines of investigation and technologies that are letting us to peer into the most distant realms of the cosmos. But also at the behavior of matter and energy on the smallest of scales. Remarkably, our growing understanding of this kingdom of the ultra-tiny, inside the nuclei of atoms, permits us to glimpse the largest vistas of space and time. In ancient times, most observers saw the stars as a sphere surrounding the earth, often the home of deities. The Greeks were the first to see celestial events as phenomena, subject to human investigation rather than the fickle whims of the Gods.
One sky-watcher, for example, suggested that meteors are made of materials found on Earth… and might have even come from the Earth. Those early astronomers built the foundations of modern science. But they would be shocked to see the discoveries made by their counterparts today. The Continue reading How Large is the Universe?→
Solar forecasters predict the Sun will reach the peak of its eleven year cycle sometime in 2013. Meanwhile, after one of the least active solar minimums on record, the Sun is rising again. Here are some of the highlights captured so far by NASA satellites: powerful X-class flares, flamboyant CMEs, and swirling turbulence on its surface. Our favorite is the “magnificent CME” from August 2012. You can be sure there’s more of this to come.
The answer to this question may depend on whether Stephen Hawking was right in his theory that describes how black holes shed mass and eventually decay. Time is flying by on this busy, crowded planet as life changes and evolves from second to second. At the same time, the arc of the human lifespan is getting longer: 67 years is the global average, up from just 20 years in the Stone Age.
Modern science provides a humbling perspective. Our lives, indeed even that of the human species, are just a blip compared to the Earth, at 4.5 billion years and counting, and the universe, at 13.7 billion years.
It now appears the entire cosmos is living on borrowed time. It may be a blip within a much grander sweep of time. When, we now ask, will time end?
Our lives are governed by cycles of waking and sleeping, the seasons, birth and death. Understanding time in cyclical terms connects us to the natural world, but it does not answer the questions of science.
What explains Earth’s past, its geological eras and its ancient creatures? And where did our world come from? How and when will it end? In the revolutions spawned by Copernicus Continue reading When Will Time End?→
All across the immense reaches of time and space, energy is being exchanged, transferred, released, in a great cosmic pinball game we call our universe.
How does energy stitch the cosmos together, and how do we fit within it? We now climb the power scales of the universe, from atoms, nearly frozen to stillness, to Earth’s largest explosions. From stars, colliding, exploding, to distant realms so strange and violent they challenge our imaginations. Where will we find the most powerful objects in the universe?
Today, energy is very much on our minds as we search for ways to power our civilization and serve the needs of our citizens. But what is energy? Where does it come from? And where do we stand within the great power streams that shape time and space?
Energy comes from a Greek word for activity or working. In physics, it’s simply the property or the state of anything in our universe that allows it to do work. Whether it’s thermal, kinetic, electro-magnetic, chemical, or gravitational.
Our Milky Way may harbor millions of black holes… the ultra dense remnants of dead stars. But now, in the universe far beyond our galaxy, there’s evidence of something far more ominous. A breed of black holes that has reached incomprehensible size and destructive power. Just how large, and violent, and strange can they get?
A new era in astronomy has revealed a universe long hidden to us. High-tech instruments sent into space have been tuned to sense high-energy forms of light — x-rays and gamma rays — that are invisible to our eyes and do not penetrate our atmosphere. On the ground, precision telescopes are equipped with technologies that allow them to cancel out the blurring effects of the atmosphere. They are peering into the far reaches of the universe, and into distant caldrons of light and energy. In some distant galaxies, astronomers are now finding evidence that space and time are being shattered by eruptions so vast they boggle the mind.
We are just beginning to understand the impact these outbursts have had on the universe: On the shapes of galaxies, the spread of elements that make up stars and planets, and ultimately the very existence of Earth. The discovery Continue reading The Largest Black Holes in the Universe→
From NASA’s Scientific Visualization Studio. Supercomputer models of merging black holes reveal properties that are crucial to understanding future detections of gravitational waves. This movie follows two orbiting black holes and their accretion disk during their final three orbits and ultimate merger. Redder colors correspond to higher gas densities.
The initial magnetic field of the gas is amplified by 100 times. Magnetic fields evacuate the region above the black hole and produce a thinner, hotter, denser disk in the immediate vicinity of the black hole than in simulations without them. The merged black hole resides within a hot, dense disk of ionized gas. The base of the low-density funnel is visible near the center. Such a structure could support a jet of particles moving near the speed of light, although one was not yet produced before the simulation ended. This model, which includes the effects of general relativity, magnetic fields and gas dynamics, produced an electromagnetic signal 10,000 brighter than in simulations that ignored the gas effects.
The sequence ends with a simulation of the merger of two black holes and the resulting emission of gravitational radiation. The colored fields represent a component of the curvature of space-time. The outer red sheets Continue reading Black Hole Merger Simulation→
NASA’s Curiosity rover mission has found evidence a stream once flowed across the area on Mars where the rover is driving. There is earlier evidence for the presence of water on Mars, but this evidence — images of rocks containing ancient streambed gravels — is the first of its kind. Scientists are studying the images of stones cemented into a layer of conglomerate rock. The sizes and shapes of stones offer clues to the speed and distance of a long-ago stream’s flow.
The sizes and shapes of stones offer clues to the speed and distance of a long-ago stream’s flow. “From the size of gravels it carried, we can interpret the water was moving about 3 feet per second, with a depth somewhere between ankle and hip deep,” said Curiosity science co-investigator William Dietrich of the University of California, Berkeley. “Plenty of papers have been written about channels on Mars with many different hypotheses about the flows in them. This is the first time we’re actually seeing water-transported gravel on Mars. This is a transition from speculation about the size of streambed material to direct observation of it.”
Astronomers using NASA’s Swift satellite recently detected a rise in high-energy X-rays from a source toward the center of our Milky Way galaxy. The outburst, produced by a rare X-ray nova, came from a previously unknown stellar-mass black hole.
An X-ray nova is a short-lived X-ray source that appears suddenly, reaches its emission peak in a few days and then fades out over a period of months. The outburst arises when a torrent of stored gas suddenly rushes toward one of the most compact objects known, either a neutron star or a black hole.
The rapidly brightening source triggered Swift’s Burst Alert Telescope twice on the morning of Sept. 16, and once again the next day. Named Swift J1745-26 after the coordinates of its sky position, the nova is located a few degrees from the center of our galaxy toward the constellation Sagittarius. While astronomers do not know its
precise distance, they think the object resides about 20,000 to 30,000 light-years away in the galaxy’s inner region.
Ground-based observatories detected infrared and radio emissions, but thick clouds of obscuring dust have prevented astronomers from catching Swift J1745-26 in visible light.