A black-hole system in a neighboring galaxy is twice as bright as astronomers had thought possible, a new study reports.

The incredible luminosity of the system in question, which resides about 22 million light-years from Earth in the Pinwheel Galaxy, may force a rethink of the theories that explain how some black holes radiate energy, researchers said.

"As if black holes weren't extreme enough, this is a really extreme one that is shining as brightly as it possibly can," study co-author Joel Bregman of the University of Michigan said in a statement. "It's figured out a way to be more luminous than we thought possible."

The astronomers studied a system called ULX-1, which consists of a black hole and a companion star that orbit each other. As its name suggests - ULX is short for "ultraluminous X-ray source" - ULX-1 generates prodigious amounts of high-energy X-ray light, which is emitted by material spiraling down into the black hole's maw.

Comet ISON is hurtling toward the sun today at 240,000 mph and, despite the rising heat, the comet appears to be intact. Yesterday, reports of fading spectral lines from the comet's core raised concerns that the icy nucleus might be disintegrating. Current images from NASA and ESA spacecraft, however, show the comet still going strong. Comet ISON has just entered the field of view of the Solar and Heliospheric Observatory (SOHO):
The comet's entrance coincides with a bright CME racing away from the sun's southwestern limb. Astronomers have been wondering what might happen if a CME strikes Comet ISON. This CME, however, will probably miss. The source of the cloud is a farside active region, which is not directly facing the comet.

China's first-ever moon lander will be launched early next month. The robotic mission will include a rover, which was named after the Moon Rabbit of Chinese folklore. The landing may compromise NASA's current lunar mission.

The lander and the rover are both part of the Chang'e-3 mission, the third in a series named after the Chinese moon goddess. Continuing the folklore naming trend is the name of the rover, which was called Yutu after the goddess's pet rabbit.

Yutu, also known as Jade Rabbit, is the Chinese counterpart to the western 'man in the moon', a creature, whose outline is said to be visible on the moon's surface. The legend envisions the rabbit compounding the elixir of immortality for Chang'e.

The name for the six-wheeled 120-kg rover was chosen in an online poll, with 3.4 million people taking part, the Xinhua news agency reported.

"Yutu is a symbol of kindness, purity and agility, and is identical to the moon rover in both outlook and connotation," it quoted Li Benzheng, deputy commander-in-chief of China's lunar program, as saying.

"Yutu also reflects China's peaceful use of space," he added.

Asteroid 2013 NJ is just one object on NASA's list of near-Earth objects, but it's remarkable in that it flew by significantly closer than anything else on the list. Passing by at about 2.5 times the distance to the moon, it was close enough to be visible to the naked eye, even though its diameter is relatively small at 120-260 meters.

Luckily for us, when something passes extremely close in terms of space, say 2.5 lunar distances, it's actually still a pretty large distance away in actuality. Unluckily, the size of objects is also subjected to that relative sense of scale, as something that's relatively small in space terms, say 120-260 meters, is actually pretty large if it comes hurtling towards you.

Incoming comet ISON was obviously on a perilous path. The "dirty snowball" was on course to swing by the sun less than one solar diameter above the sun's searing surface on 28 November, Thanksgiving Day in the United States. This view from the SOHO spacecraft dramatically illustrates ISON's close passage through the sun's streaming solar wind and around the sun (here inserted from another image to give a sense of scale).

But astronomers are reporting ominous signs, such as a peak in overall brightness, suggesting that the shrouded ball of ice and dust at the center of the comet has broken up into nothing more than a cloud of dust. Direct confirmation of ISON's disintegration must await spacecraft observations in the next few days.

For months, all eyes in the sky have pointed at the comet that's zooming toward a blisteringly close encounter with the sun.

The moment of truth comes Thursday -- Thanksgiving Day.

The sun-grazing Comet ISON, now thought to be less than a mile wide, will either fry and shatter, victim of the sun's incredible power, or endure and quite possibly put on one fabulous celestial show.

Talk about an astronomical cliffhanger.

Even the smartest scientists are reluctant to lay odds.

In our November 23, the overall message was that not much had changed, and the comet appeared to be keeping it all together as it approached the Sun.

That situation may now have changed.

We are seeing reports online that molecular emission from the comet has fallen dramatically, meanwhile dust production seems to be enormous. What this could indicate is that the nucleus has completely disrupted, releasing an enormous volume of dust while significantly reducing emission rates. Fragmentation or disruption of the nucleus has always been the highest risk factor for this comet so if this has indeed happened then while unfortunate, it would not be a surprise.

However, these reports are new, and while they are undoubtedly valid, we do still need to keep observing the comet to be sure what it happening. Remember: Comet ISON is a dynamically new sungrazing comet, fresh in from the Oort Cloud, and the last time we saw an object like this was never! Furthermore, a sungrazing comet just three days from perihelion has never been studied in this kind of detail - we're breaking new ground here! When we factor in your standard "comets are unpredictable" disclaimer, what we have is a huge recipe for the unknown.

Comet ISON makes solar approach on Thursday, passing a mere 720,000 miles from the solar surface. It'll get hot. This could cause a break-up, with fragments then heading on as yet unpredictable trajectories. Could this pose a threat to Earth? Stuart Clark at the Guardian has the following obs:

"If it survives an encounter with the sun this week, comet Ison will put on an impressive early morning display in the run-up to Christmas. But anyone hoping for a Bethlehem-style celestial sign on the big day will be disappointed. By then the comet will probably be too faint to see with a naked eye.

Ison is currently speeding towards a fiery encounter on Thursday, which could destroy it. It will pass 720,000 miles above the solar surface, 130 times closer than our planet ever reaches.

The intense sunlight will heat the comet to about 2,700C, speeding up its evaporation. In the past some comets have been seen to vaporise under such an onslaught.

Lovejoy skimmed 85,000 miles above the solar surface. It survived, but with very little of its 0.3-mile-wide nucleus left. Ison is estimated to be two miles wide, and its evaporating ices have already created a tail that stretches 8m miles through space.

"I'm not a gambling man but if I had to bet a fiver, I'd say Ison will survive,' said Brown.

Even if the majority of the comet emerges, fragments could still be blasted off. This would lead to a much more spectacular tail for skywatchers to see in December's sky. For viewers on Earth, the best time to start looking will be in the first and second weeks of December. By then the tail should be extremely well developed and Ison will appear as a ghostly fan shape in the pre-dawn sky.

The comet will also be visible in the western sky at sunset. It will be more difficult to spot at this time, however, because the tail is horizontal and immersed in the twilight. Better to set the alarm clock and rise early, when it will be visible in a truly dark sky."

• Images from H-1 camera on NASA's Solar Terrestrial Relations Observatory

• In the image the comet shows up clearly, appearing to still be intact

For months, all eyes in the sky have pointed at the comet that's zooming toward a blisteringly close encounter with the sun.

And now NASA has released a high resolution image of the streaking comet that look like a swimming tadpole.

It was captured by the H-1 camera on board NASA's Solar Terrestrial Relations Observatory on November 21.

The story of human evolution just got even more bizarre. The genome of an extinct hominin species, the Denisovans, contains unusual snippets of DNA that seem to have come from yet another group.

It could be evidence of an entirely new species of hominin, as yet unknown to science. Alternatively, it could be our first genetic record of one of the many species known only from their fossils.

The new hominin has left its traces in the genome of a Denisovan, an extinct hominin known to exist from a finger bone and two teeth found in a Siberian cave. Nobody knows what Denisovans looked like because there are so few fossils. But geneticists have managed to sequence their entire genome to a high degree of accuracy.

David Reich of Harvard Medical School in Boston, Massachusetts, has now taken a close look at the Denisovan genome and found that some stretches of it don't fit. He presented his findings at a Royal Society discussion meeting on ancient DNA in London, UK, on Monday.