The Sun’s angry red spot

Alan Friedman, astrophotographer, caught the culprit sunspot, Active Region 1429, as it was nearing the edge of the Sun on Monday.

Note all the prominences, giant towers of gas at the edge of the Sun, and the simply enormous filament of plasma at the top of the Sun’s disk.

It’s about 400,000 km (240,000 miles) across. This is the same distance from the Earth to the Moon!

The origins of a torus in a Galactic Nucleus

An artist's conception of a quasar, with a Chandra X-ray Observatory image of the quasar GB1508+5714 inset.

The data reveal a jet of high-energy particles that extends more than 100,000 light years from the supermassive black hole powering the quasar.

A new study shows for the first time that a torus of gas and dust will naturally form around the nuclear black hole as material falls in toward the nucleus.

Credit: NASA/Chandra

Quasars are among the most energetic objects in the universe, with some of them as luminous as ten thousand Milky Way galaxies.

Quasars are thought to have massive black holes at their cores, and astronomers also think that the regions around the black holes actively accrete matter, a process that releases vast amounts of energy and often ejects a powerful, narrow jet of material.

Quasars can be seen even when they are very far away, because they are so bright, and this combination of being both highly energetic and located at cosmological distances makes them appealing to astronomers trying to figure out the nature of galactic center black holes (our own Milky Way has one) and the conditions in the early universe that prompt these monsters to form.

The situation may be about to change. The violent activity around a black hole is very difficult to analyze with just pen and paper, and so for years researchers have tried to use computer simulations to identify what happens.

These simulations have faced a major challenge: tracing the detailed flow of material from galaxy-wide scales of hundreds of thousands of light-years down into the central tenth of a light-year around the black hole.

It has just been too hard to keep track of everything at such a fine scale across such a large one.

CfA astronomers Chris Hayward and Lars Hernquist, together with ex-CfA member Phil Hopkins and a fourth colleague, have figured out a way to deal with the computational dilemma.

They use a clever scheme of multi-scale "zoom-ins" which allows them to track and model, in a physically consistent way, selected parcels of gas as they move inward towards the torus.

Their simulations lead them to reach two very significant conclusions. First, they show that a dusty torus is likely to be produced around the black hole - in the past it had been postulated in order to explain the various morphologies but had never been demonstrated, even in a simulation.

Secondly, the scientists show that the torus is not just a passive screen: it plays an active role in feeding gas and dust into the accretion disk around the black hole itself.

Provided by Harvard-Smithsonian Center for Astrophysics

NASA Spitzer Telescope Image: Hidden Jet

Spitzer Image HH-34

NASA's Spitzer Space Telescope took this image of a baby star sprouting two identical jets (green lines emanating from fuzzy star).

The jet on the right had been seen before in visible-light views, but the jet at left, the identical twin to the first jet, could only be seen in detail with Spitzer's infrared detectors (IRAC).

The left jet was hidden behind a dark cloud, which Spitzer can see through.



The twin jets, in a system called Herbig-Haro 34 (HH-34), are made of identical knots of gas and dust, ejected one after another from the area around the star.

By studying the spacing of these knots, and knowing the speed of the jets from previous studies, astronomers were able to determine that the jet to the right of the star punches its material out 4.5 years later than the counter-jet.

Hubble Images

The new data also reveal that the area from which the jets originate is contained within a sphere around the star, with a radius of 3 astronomical units.

An astronomical unit is the distance between Earth and the sun. Previous studies estimated that the maximum size of this jet-making zone was 10 times larger.

The wispy material is gas and dust. Arc-shaped bow shocks can be seen at the ends of the twin jets. The shocks consist of compressed material in front of the jets.

The Herbig-Haro 34 (HH-34) jets are located at approximately 1,400 light-years away in the Orion constellation.

Image Credit: NASA/JPL-Caltech

NASA SDO: Shifting Plasma Images

NASA's Solar Dynamics Observatory has released images of plasma shifting back and forth above the sun's surface for 30 hours.

On February 7th - 8th an active region rotating into view provides a bright backdrop to the gyrating streams of plasma.

The particles are being pulled in various directions by competing magnetic forces.

They are tracking along strands of magnetic field lines.

This kind of detailed solar observation with high-resolution frames and a four-minute cadence was not possible until SDO, which launched two years ago on February 11th, 2010.

Picture: NASA SDO / Rex Features

RXTE Helps Pinpoint Launch of Bullets in Black Hole Jet

Radio imaging by the Very Long Baseline Array (top row), combined with simultaneous X-ray observations by NASA's RXTE (middle), captured the transient ejection of massive gas "bullets" by the black hole binary H1743-322 during its 2009 outburst.

By tracking the motion of these bullets with the VLBA, astronomers were able to link the ejection event to the disappearance of X-ray signals seen in RXTE data.

These signals, called quasi-periodic oscillations (QPOs), vanished two days earlier than the onset of the radio flare that astronomers previously had assumed signaled the ejection.

(Credit: NRAO and NASA's Goddard Space Flight Center).

Giant Black Holes Keep Powerful Radio Jets Close

This artist's illustration depicts scientists' new understanding of the giant black hole at the core of galaxy M87. 

The bright radio 'core' of the jet base is located very close to the central black hole no larger than about 10 times the size of the event horizon.

CREDIT: NAOJ

The powerful jets of radio waves that can explode from monster black holes at the center of galaxies may erupt from much closer to these giants than previously thought, scientists say.

Although black holes entrap anything that falls onto them, a vast amount of energy can radiate outward from matter rushing into the black holes. In this way, radio telescopes can spot black holes by the radio jets they can give off. But the way these radio jets form is uncertain.

To uncover their roots, researchers investigated a nearby source of them, the black hole at the heart of galaxy M87, a monster about 23.5 billion miles (37.8 billion kilometers) wide and 6 billion times the mass of the sun, study lead author Kazuhiro Hada, an astronomer at the Graduate University for Advanced Studies in Tokyo stated.

Lightning Jets and Sprites

The ancient Greeks might have thought Zeus was furious with heaven itself. The power of lightning strikes and Sprites, that shoot upwards from storm clouds has been measured for the first time – and they turn out to be every bit as powerful as normal lightning.

First caught on camera in 2003, "gigantic jets" shoot upwards from thunderclouds and can reach altitudes above 80 kilometres. But it wasn't until 21 July last year that Steven Cummer at Duke University in Durham, North Carolina, and his colleagues managed to measure the electrical discharge from a single gigantic jet, released from tropical storm Cristobal.

"No one had been very close to one with the right radio instrumentation before," Cummer says. "So we didn't know whether they just petered out without doing anything much, or whether they actually took some charge and dumped it somewhere."