Showing posts with label space. Show all posts

In celebration of the 21st anniversary of the Hubble Space Telescope’s deployment into space, astronomers at the Space Telescope Science Institute in Baltimore, Md., pointed Hubble’s eye to an especially photogenic group of interacting galaxies called Arp 273.

The larger of the spiral galaxies, known as UGC 1810, has a disk that is tidally distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. A swath of blue jewels across the top is the combined light from clusters of intensely bright and hot young blue stars. These massive stars glow fiercely in ultraviolet light.

The smaller, nearly edge-on companion shows distinct signs of intense star formation at its nucleus, perhaps triggered by the encounter with the companion galaxy.

A series of uncommon spiral patterns in the large galaxy is a tell-tale sign of interaction. The large, outer arm appears partially as a ring, a feature seen when interacting galaxies actually pass through one another. This suggests that the smaller companion actually dived deep, but off-center, through UGC 1810. The inner set of spiral arms is highly warped out of the plane with one of the arms going behind the bulge and coming back out the other side. How these two spiral patterns connect is still not precisely known.

The larger galaxy in the UGC 1810 – UGC 1813 pair has a mass that is about five times that of the smaller galaxy. In unequal pairs such as this, the relatively rapid passage of a companion galaxy produces the lopsided or asymmetric structure in the main spiral. Also in such encounters, the starburst activity typically begins in the minor galaxies earlier than in the major galaxies. These effects could be due to the fact that the smaller galaxies have consumed less of the gas present in their nucleus, from which new stars are born.

Arp 273 lies in the constellation Andromeda and is roughly 300 million light-years away from Earth. The image shows a tenuous tidal bridge of material between the two galaxies that are separated by tens of thousands of light-years from each other. The interaction was imaged on December 17, 2010, with Hubble’s Wide Field Camera 3 (WFC3).

This Hubble image is a composite of data taken with three separate filters on WFC3 that allow a broad range of wavelengths covering the ultraviolet, blue, and red portions of the spectrum.

via Hubble Site News Release

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Reggae mix 2013 for Ganja Smoker !

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2013’s solar maximum could be weakest since the dawn of the space age

So this is unexpected. The Sun is currently at the peak of its 11-year solar cycle. It should be awash with sunspots, solar flares, coronal mass ejections and the like. And yet, observations indicate our parent star has actually been pretty quiet this year – so quiet, in fact, this years solar max could go down as the weakest in a century.

"It’s the smallest maximum we’ve seen in the Space Age," said David Hathaway of NASA’s Marshall Space Flight Center yesterday via teleconference.

Earlier this year, there was speculation that scientists had miscalculated the maximum of the current cycle, though it’s become increasingly apparent that no, this is the maximum, it’s just a quiet one. And that, according to NASA, isn’t necessarily uncommon:

Conventional wisdom holds that solar activity swings back and forth like a simple pendulum. At one end of the cycle, there is a quiet time with few sunspots and flares. At the other end, Solar Max brings high sunspot numbers and solar storms. It’s a regular rhythm that repeats every 11 years.

Reality, however is more complicated. Astronomers have been counting sunspots for centuries, and they have seen that the solar cycle is not perfectly regular. For one thing, the back-and-forth swing in sunspot counts can take anywhere from 10 to 13 years to complete; also, the amplitude of the cycle varies. Some solar maxima are very weak, others very strong.

Back in March, solar physicist Dean Pesnell of the Goddard Space Flight Center hypothesized that the Sun could be experiencing a lull between two peaks in sunspot activity. A similar "twin peak" solar maximum, Pesnell said, occurred back in 1989, and again in 2001. The first peak of the current solar maximum, he said, reached its zenith in 2011, dipped in 2012, and continued through the beginning of 2013. "I am comfortable in saying that another peak will happen in 2013 and possibly last into 2014," he predicted at the time.

But 2014 is fast approaching, and still no signs of a second spike. Is this a bad thing? Hardly. Disappointing? You might think so, said Hathaway at yesterday’s conference, "but it’s quite the contrary."

SPACE.com gives an example of what Hathaway and his colleauges are taking away from this cycles tamer-than-usual antics:

North-south, or meridional, flows carry magnetic elements from sunspots to the sun’s poles, building up the polar magnetic fields until they eventually flip around the time of the solar maximum, Hathaway explained. Scientists are noticing that the strength of the polar fields when a new cycle begins influences the strength of the cycle, he added. For example, weak polar fields observed in 2008 led to the current weak cycle, while strong polar fields in 1986 spawned a strong Cycle 22.

The polar fields have been slowly reversing at this maximum, Hathaway said, suggesting that they are not going get much stronger during Cycle 24. This also sets the stage for an even smaller maximum during Cycle 25, scientists believe.

"We’re seeing fields that suggest the next sun cycle will be even weaker than this one," Hathaway said.

[...]

Read the full article at: io9.com

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These Cubesats Could Use Plasma Thrusters to Leave Our Solar System

Artist concept of a 5 kg CubeSat with CubeSat Ambipolar Thruster (CAT) firing in low Earth orbit. Via Kickstarter.

Cubesats are all the rage these days: they’re usually inexpensive and quick to build and they can tag along on launches already scheduled for other things. We think of cubesats as being almost “disposable” satellites – tiny spacecraft that go into Earth orbit for a short time, do their science and then burn up harmlessly in Earth’s atmosphere. But a team of scientists have a more long-term, long-distance plan for their cubesats. Benjamin Longmier and James Cutler from the University of Michigan want to build cubesats that have tiny plasma thruster engines that could propel them into deep space, maybe even interstellar space.
They have a vision of their plasma-thruster cubesat waving as it speeds past the Voyager spacecraft at the edge of our Solar System.

They are working on what they call the CubeSat Ambipolar Thruster (CAT), a new plasma propulsion system. This thruster technology doesn’t exist all in one piece yet, but Longmeir and Cutler said they could put it together in months, with just a little funding. The CAT plasma thruster will propel a 5kg satellite into deep space, far beyond Earth orbit, at 1/1000th the cost of previous missions.
They’ve begun a $200,000 Kickstarter campaign to help fund their project. Their ideas of what these thruster propelled cubesats could do are mind-bogglingly exciting: flying through the plumes of Enceladus to look for life, studying and tagging asteroids, formation flying through Earth’s magnetosphere to learn more about solar flares and the aurora or just an interplanetary message in a bottle lasting for hundreds of millions of years in orbit around the Sun.

They think they can get a satellite up and flying within 18 months.
“The traditional funding process starts with some seed data, a large government grant and a large number of milestones and gates to go through,” said Longmier in a press release from the University of Michigan. “We’d like to leverage Kickstarter funds to compress that timeline and go from initial seed data to flight in about 18 months, a much faster time scale than is possible with traditional grants.”

The cubesats would be about as big as a loaf of bread and the thrusters – the first of its kind — would use superheated plasma directed through a magnetic field to propel the CubeSat. The duo says that with this technology, exploring interplanetary space and eventually other planets would become faster and cheaper than ever before. While plasma rockets have been used before, they’ve only been used on big spacecraft like Deep Space 1 and DAWN. Longmier and Cutler are miniaturizing the system. Most of the thruster components have been built and have been tested individually, but they need help through Kickstarter to assemble everything into one compact thruster unit for testing the integrated components in the lab, then in Earth orbit, and then interplanetary space. They’ve got more info on how the thrusters work on their Kickstarter page. I dare you to tell me this isn’t exciting

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60 Billion Habitable Planets in the Milky Way Alone?

60 Billion Habitable Planets in the Milky Way Alone? Astronomers say Yes!

An artist’s conception of how common exoplanets are throughout the Milky Way Galaxy. Image Credit: Wikipedia

A new study suggests that the number of habitable exoplanets within the Milky Way alone may reach 60 billion.
Previous research performed by a team at Harvard University suggested that there is one Earth-sized planet in the habitable zone of each red dwarf star. But researchers at the University of Chicago and Northwestern University have now extended the habitable zone and doubled this estimate.

The research team, lead by Dr. Jun Yang considered one more variable in their calculations: cloud cover. Most exoplanets are tidally locked to their host stars – one hemisphere continually faces the star, while one continuously faces away. These tidally locked planets have a permanent dayside and a permanent nightside.
One would expect the temperature gradient between the two to be very high, as the dayside is continuously receiving stellar flux, while the nightside is always in darkness. Computer simulations that take into account cloud cover show that this is not the case.
The dayside is covered by clouds, which lead to a “stabilizing cloud feedback” on climate. It has a higher cloud albedo (more light is reflected off the clouds) and a lower greenhouse effect. The presence of clouds actually causes the dayside to be much cooler than expected.
“Tidally locked planets have low enough surface temperatures to be habitable,” explains Jang in his recently published paper. Cloud cover is so effective it even extends the habitable zone to twice the stellar flux. Planets twice as close to their host star are still cool enough to be habitable.
But these new statistics do not apply to just a few stars. Red dwarfs “represent about ¾ of the stars in the galaxy, so it applies to a huge number of planets,” Dr. Abbot, co-author on the paper, told Universe Today. It doubles the number of planets previously thought habitable throughout the entire galaxy.

Not only is the habitable zone around red dwarfs much larger, red dwarfs also live for much longer periods of time. In fact, the Universe is not old enough for any of these long-living stars to have died yet. This gives life the amount of time necessary to form. After all, it took human beings 4.5 billions years to appear on Earth.
Another study we reported on earlier also revised and extrapolated the habitable zone around red dwarf stars.
Future observations will verify this model by measuring the cloud temperatures. On the dayside, we will only be able to see the high cool clouds. A planet resembling this model will therefore look very cold on the dayside. In fact, “a planet that does show the cloud feedback will look hotter on the nightside than the dayside,” explains Abbot.
This effect will be testable with the James Webb Space Telescope. All in all, the Milky Way is likely to be teeming with life.