Tag Archives: astronomy

Blue Galaxy Could Hold Clues To The Origin Of The Universe

Looking for clues about the early universe is often like the proverbialneedle-in-a-haystack, but once in a while astronomers are able to spot objects thatcan open new doors into the distant past.

This is the case of AGC 198691, a small blue galaxy located 30 million light-years away in the constellation of Leo Minor. The object has the smallest fraction of heavy elementsreferred to as metals in astronomyever seen in a galaxy, indicating that its material hasnt changed much since the Big Bang. A paper describing the discovery was published in the Astrophysical Journal.

“Finding the most metal-poor galaxy ever is exciting since it could help contribute to a quantitative test of the Big Bang,” Professor John J. Salzer, of Indiana University andsenior author of the paper, said in a statement.”There are relatively few ways to explore conditions at the birth of the universe, but low-metal galaxies are among the most promising.”

The metals like carbon, oxygen, and so onare produced by stars and spread throughout interstellar space by supernovae. AGC 198691 has just1.3 percent the metallicityof the Sun, a sign that very little star formation has happened since its formation.

Without much “contamination,”the composition of the galaxy, which has been nicknamed Leoncino (Italian for “little lion”), can be used to compare whether the predicted abundance of primordial hydrogen and helium matches with the observations.

Leoncinos uniqueness doesnt stop at its low metallicity. The galaxy is a “dwarf,” about 1,000 light-years across and made of a few million stars. An average system like the Milky Way is about 100 times wider and containsbetween 200 and 400 billion stars. Although Leoncino has some recently formed stars, responsible for its blue color, the galaxy has the lowest luminosity ever observed for this kind of object.

“We’re eager to continue to explore this mysterious galaxy,” added Salzer. “Low-metal-abundance galaxies are extremely rare, so we want to learn everything we can.”

The team is pursuing follow-up observations with several instruments, including the Hubble Space Telescope. A better understating of these galaxies will lay the groundwork for the potential detection of even more metal-poorobjects by the next generation of observatories.

Read more: http://www.iflscience.com/space/blue-galaxy-gives-clues-about-early-universe

Russian Satellite Could Become The “Brightest Star” In Our Night Sky

A team of Russian scientists is planning to launch a unique satellite into orbit, with the goal of making it the brightest star in our skies (aside from the Sun, of course) with the use of a giant reflective sheet of material.But there are some possible negative consequences if this ever gets off the ground, notably for amateur and professional astronomers alike.

The team of engineers behind this project, from Moscow State Mechanical Engineering University (MAMI), is running a crowdfunding campaign on the platform Boomstarter. The spacecraft is known as Mayak,or Beacon in English, and they have raised more than 1.7 million rubles ($22,000.)Having met their funding goal, they are now aiming for a launch in summer this year on a Soyuz-2 rocket with the assistance of Roscosmos, the Russian space agency.

The small spacecraft, roughly the size of a loaf of bread, will unfurl a giant pyramid-shaped solar reflector in orbit, with the aim of shining brighter than any other star. The reflector, 16 square meters (170 square feet) in size, is supposedly 20 times thinner than human hair, made of a thin polymer film. This spacecraft doesn’t have any other scientific purpose, although the team notes that a similar structure could be used to remove defunct satellites from orbit.

“We want to show that space exploration is something exciting and interesting, but most importantly that today it is accessible to everybody who is interested,” project leader Alexander Shaenko said, reported Sputnik News.

The team is planning to place the spacecraft in a Sun-synchronous orbit 600 kilometers (370 miles)above the ground. This means it will always be in sunlight, and thus will always be shining in the night sky at different locations as Earth rotates. At this height, the spacecraft will also be able to avoid large effects from atmospheric drag, so it could feasibly orbit for weeks, months, or even years.

Whether such a proposal can actually work remains to be seen. But if it does, it runs the risk of a backlash from scientific and environmental groups, depending on how bright it is. Some, like Russia Today, have suggested it may shine as bright as the Moon, although that is questionable. We ran some calculations, and came out with a magnitude of -3.6, which would be the fourth brightest object in the sky after the Sun, the Moon, and Venus.

The brightest star at the moment is Sirius, but Mayak has the potential to be brighter.T. Jittasaiyapan/Shutterstock

Nonetheless, if it is excessively bright, it could cause havoc for astronomers who rely on darkness to observe the universe. “We fight so hard for dark skies in and around our planet, Nick Howes, an astronomer and former deputy director of the Kielder Observatory in Northumberland, told IFLScience. To see this being potentially ruined by some ridiculous crowdfunded nonsense makes my heart simply despair.

Gemma Lavender, astronomer and editor for All About Space magazine, was less sure about the impact. It’s unlikely to cause any significant problems for astronomers although, of course, if it happens to move in front of, say, a faint galaxy when astronomers are trying to observe it, then it’ll cause some type of interference, she said. The sky is massive though, so the chances of this happening are quite small.

The proposal isnt wholly dissimilar to the Russian proposal to build a giant space mirror back in the 1990s to turn night into day in certain locations. Back then, that proposal wasnt exactly met favorably. Well have to wait and see if Mayak fares better in the public eye.

Photo Gallery

Read more: http://www.iflscience.com/space/russian-satellite-could-become-brightest-star-night-sky

9 Terrifyingly Awesome Facts About Asteroids

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asteroid

Phil Plait, also known as the “Bad Astronomer,” is a Discover columnist known for making really complicated space stuff (Black holes! White dwarves! Spacetime!) not only totally understandable, but completely fascinating.

Plait made a stop in Portland, Ore. on tour with his latest book, Death from the Skies, to speak at Science Pub, a monthly summit of beer and geeks hosted by Portland’s excellent science museum, OMSI.

Plait’s talk was packed to the gills with both avid Bad Astronomy fans and science-minded folks curious about an astronomer’s take on the end of the world. Here are our favorite asteroid factoids.

1. Objects From Space Hit the Earth… A lot

We see mini-asteroids (meteoroids) crossing paths with Earth quite often, but most of time they fall to the earth as no bigger than a grain of sand or burn up altogether. “It seems like these things are whizzing past us all the time,” Plait says. “That’s because they are.”

2. Asteroids Kind of Look Like Potatoes… Or Dog Bones

According to Phil Plait, it’s a common fact that asteroids often look a lot like potatoes. But Kleopatra, one of Plait’s favorites, is as big as a state and shaped like a dog bone. Kleopatra is actually so big that it has a couple of moons orbiting it as it tumbles through space.

3. Asteroids Can Have Mountains Taller Than Mount Everest

The asteroid known as Vesta boasts a mountain that puts even Everest to shame. And Vesta isn’t the biggest asteroid around, either — that honor goes to Ceres, a dwarf planet that’s 590 miles in diameter.

4. The biggest Asteroid Was Discovered in 1801

We’ve known about Ceres since 1801, when Italian astronomer Giuseppe Piazzi came across the massive body of rock and ice while looking for a star. He initially believed it to be a comet, but now we know Ceres to be much more on par with the size of a small planet.

5. Hollywood Usually Gets it Wrong

Plait thinks Armegeddon is up there with the least scientifically accurate movies ever cooked up in Hollywood. In Armageddon, an asteroid headed toward Earth is blown up into two halves. Among the inaccuracies, Plait noted that there’s no asteroid as big as Texas and if there was we’d know about it for well more than 18 days before it was set to impact Earth.

But not all movies go quite so wrong. Plait does like Deep Impact, another film about an asteroid hitting Earth from the same year. Plait thinks the depiction of the asteroid’s impact and its ensuing wildfires and tsunamis is actually “fairly accurate.” That’s terrifying.

6. Even Tiny Asteroids Are Dangerous

The main reason asteroids are dangerous is because they’re hurtling through space so fast. Asteroids fall to Earth at 50 times the speed of a rifle bullet. An asteroid’s impact could well exceed 50 megatons, the impact of the Soviet Union’s AN602 hydrogen bomb and the largest nuclear weapon ever detonated on Earth. You can even play around with an asteroid impact calculator if you’re curious about just how devastating an Earth impact could be.

7. A Group of Scientists Is Taking the End of the World Very, Very Seriously

The B612 foundation is a privately funded organization on a mission to create a “comprehensive, dynamic map” of the inner solar system. The map will identify the current location of asteroids that could pose a threat to Earth and provide data on just how close to Earth they might pass in the future. Worried? You probably should be. You can always donate to the B612 foundation — it might help you sleep at night.

8. Scientists Are Monitoring an Asteroid Headed for Earth in 2029

An asteroid called Apophis is set to pass near the Earth in 2029. Initial calculations gave Apophis a 2.7% chance of striking our planet. Now we know that Apophis’s odds are much, much smaller. But the asteroid could still pass through a half mile-wide area called a “keyhole,” which would change its orbit and up its chances of impacting the Earth on April 13, 2036.

9. How to Fend Off an Asteroid: Whack it, Don’t Blow it up

It sounds like science fiction, but according to Plait, “The idea is now that if you see one of these things coming, you send a probe at it and you smack it.” Even a tiny shift in an asteroid’s velocity and path can make a huge difference if it’s impacted when far enough away in space.

Another option would be harder to pull off: “You could land a rocket on it and push it, but it would be almost impossible to physically land on it, especially for asteroids like Kleopatra that are tumbling.” That asteroid, the one shaped like a dog bone, has an irregular orbit that would make a landing hard to stick.

Learn anything surprising? We certainly did!

This article originally published at Tecca
here

Read more: http://mashable.com/2012/08/17/facts-about-asteroids/

Don’t Miss The Geminid Meteor Shower This Weekend

Stargazers are in for a treat on Sunday and Monday as the Geminid meteor shower puts on a show.

After 10 p.m. ET (3 a.m. GMT) on the nights of December 13 and 14 you should be able to see a Geminid meteor every one or two minutes on average, Sky & Telescope predicts. NASA has also created a handy tool for you to calculate the activity at your chosen location at a particular time.

The Geminids will appear to radiate out of the Gemini constellation, hence the name. However, the meteors will appear from all corners of the sky, so you dont have to look in a particular direction.

As ever with viewing meteor showers, it always easier to see them if its a clear night and youre far away from the artificial glow of cities and streetlights. Its also good to go outside half an hour before the shower starts so your eyes become acclimatized to seeing in low light.

When you see a meteor, you are witnessing bits of debris burning up as they hitEarths atmosphere at over 127,100 kilometers per hour (79,000 miles per hour). The specks of cosmic dust are fragments from the 3200 Phaethon comet. This comet, which is just1.6 kilometers (3 miles) wide, makes an orbit around the Sun every 1.4 years.

Check out the NASA website for moreinformation.

Main image credit:Henry Lee/Flickr. (CC BY-ND 2.0)

Read more: http://www.iflscience.com/space/dont-miss-geminid-meteor-shower-sunday-and-monday

Hubble Spies Huge Explosion on Faraway Star

T-pyxidis-sept-2011

NASA’s Hubble Space Telescope has given astronomers a rare look at an enormous stellar eruption, allowing them to map out the aftermath of such blasts in unprecedented detail.

Hubble photographed an April 2011 explosion in the double-star system T Pyxidis (T Pyx for short), which goes off every 12 to 50 years. The new images reveal that material ejected by previous T Pyx outbursts did not escape into space, instead sticking around to form a debris disk about 1 light-year wide around the system.

This information came as a surprise to the research team.

“We fully expected this to be a spherical shell,” study co-author Arlin Crotts of Columbia University said in a statement. “This observation shows it is a disk, and it is populated with fast-moving ejecta from previous outbursts.”

The erupting T Pyx star is a white dwarf, the burned-out core of a star much like our own sun. White dwarfs are small but incredibly dense, often packing the mass of the sun into a volume the size of Earth.

T Pyx’s white dwarf has a companion star, from which it siphons off hydrogen fuel. When enough of this hydrogen builds up on the white dwarf’s surface, it detonates like a gigantic hydrogen bomb, increasing the white dwarf’s brightness by a factor of 10,000 over a single day or so.

This happens again and again. T Pyx is known to have erupted in 1890, 1902, 1920, 1944, and 1966, in addition to the 2011 event.

Such recurrent outbursts are known as nova explosions. (Nova is Latin for “new,” referring to how suddenly novas appear in the sky.) Novas are distinct from supernovas, even more dramatic blasts that involve the destruction of an entire star.

The new study clarifies just what happens to the material ejected by such outbursts.

“We’ve all seen how light from fireworks shells during the grand finale will light up the smoke and soot from shells earlier in the show,” co-author Stephen Lawrence of Hofstra University said in a statement. “In an analogous way, we’re using light from T Pyx’s latest outburst and its propagation at the speed of light to dissect its fireworks displays from decades past.”

The study represents the first time the area around an erupting star has been mapped in three dimensions, researchers said.

The new Hubble Space Telescope observations also help refine the distance to T Pyx, pegging it at 15,600 light-years from Earth. (Past estimates have ranged between 6,500 and 16,000 light-years.)

The team presented its results on June 4 at the 222nd meeting of the American Astronomical Society in Indianapolis. The study will also be published in the June 20 issue of the Astrophysical Journal Letters.

Image courtesy of NASA, ESA, A. Crotts, J. Sokoloski, and H. Uthas (Columbia University) and S. Lawrence (Hofstra University)

This article originally published at Space.com
here

Read more: http://mashable.com/2013/06/05/hubble-star-explosion/

See Venus and Saturn Shine Together Early Tuesday

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Early Tuesday morning (Nov. 27), you’ll be able to watch two planets that will pass each other in the dawn.

The planets in question are Venus and Saturn. One planet will be slowly descending into eventual obscurity, while the other will become increasingly prominent in the days and weeks to come.

Look for Venus and Saturn shortly after 4:30 a.m. local time. The planets will appear very low above the east-southeast horizon, weather permitting. Brilliant Venus, shining with a steady silvery-white glow, will be passing about 0.6 degrees below and to the right of the much dimmer and yellower Saturn. (Your closed fist held at arm’s length covers 10 degrees of the night sky.)

About an hour later, at 5:30 a.m. local time, Saturn will high enough for good views through a telescope of its breathtakingly beautiful rings. The tilt of the rings continues to slowly increase and is now almost 18 degrees from edgewise. As for Venus, it displays a rather small gibbous shaped disk, 87% illuminated by the sun. Venus is about 70% brighter than Saturn’s larger, but duller, disk and rings.

After Tuesday morning’s rendezvous, which is known as a conjunction, the two planets will slowly go their separate ways.

Venus, which was so prominent during the summertime, is now rising later and appearing lower to the horizon in the dawn twilight. It has about another two months to go before it ultimately drops down into the bright morning twilight and disappears from our view, eventually transitioning into the evening sky by early next spring.

Saturn, on the other hand, will climb progressively higher and rise earlier, eventually becoming a prominent and well-placed evening object by the middle of spring.

If you look at both Venus and Saturn through a telescope, Venus is unquestionably the brighter of the two objects. But you might wonder how this is possible. After all, both planets are perpetually covered with clouds and their respective albedos — the proportion of the incident sunlight reflected by those clouds — are exactly the same at 76%.

Why then does Saturn appear so much duller than Venus if both are reflecting the same proportion of sunlight back toward the Earth?

The key is their distances from the sun. Compared to Venus, Saturn is 13.59 times farther away from the sun. And if we use the inverse square law — which states that the intensity of reflected sunlight is inversely proportional to the square of the distance from the sun — then 13.59 multiplied by 13.59 shows that sunlight striking Saturn’s cloud tops, is 184.69 times weaker compared to sunlight striking the cloud tops of Venus.

In any case, arise early on Tuesday and take a peek as the Venus, the Goddess of Beauty, snuggles up to Saturn, the God of Time.

Homepage image via iStockphoto, fpm.

This article originally published at Space.com
here

Read more: http://mashable.com/2012/11/26/watch-venus-saturn/

Papyrus Reveals Ancient Egyptian Astronomical Knowledge

Researchers from the University of Helsinki have proposed that ancient Egyptians 3,000 years ago were the first to record the variability of a distant star and their records could provide useful information for astronomers today.

A new paper published in PLOS ONE explains how the Egyptian Cairo Calendar from 1244 to 1163 B.C. describes the variability of a binary star system called Algol. In the calendar, there are two significant periods of time for two gods 29.6 and 2.85 days. The former relates to the period of the Moon, while the latter almost perfectly matches the variability of Algol which today is 2.867 days, or two days, 20 hours, and 49 minutes.

This theory had been proposed in 2013 but, understandably, had been met with some skepticism. However, the researchers now say they are more confident in their claims, and say that Algol relates to the deity Horus.

I would have serious doubts, if someone claimed, for example, that the Bible contains information about water in Mars, said lead author Lauri Jetsu in a statement. We claimed that Ancient Egyptian religious texts contain astrophysical information about Algol. It was no surprise to us that there were, and there still are, sceptics.

Shown is an extract of the Cairo Calendar papyrus, used courtesy of Lauri Jetsu

An eclipsing binary is a pair of stars that, as viewed from Earth, rotate around each other and block each other’s light. Thus, this particular star dims regularly in brightness as it orbits its companion. Algol is found in the constellation Perseus about 92.8 light-years from us; the larger star is about 3.5 times the radius of the Sun, and the smaller about 2.7. They are separated by about 0.062 astronomical units (AU, one AU is the Earth-Sun distance).

The variability of Algol, which can be seen with the naked eye, was thought to have been first recorded by Italian astronomer Geminiano Montanari in 1667, although it was not until 1783 that British astronomer John Goodricke suggested another object may be the cause of the dimming. Based on this latest assumption, however, the record for discovery of this star’s variability may have to be re-awarded.

Perhaps most interestingly, the discovery reveals that the variability of the star has decreased very slightly over three millennia, by about 0.017 days. Rather than being an error, the researchers postulate that this could be due to the transfer of mass between the two stars affecting their orbits.

In fact, this would be the first observation that confirms the period increase of Algol and it also gives an estimate of the mass transfer rate, added Jetsu, possibly providing an important tool for astronomers today to learn more about eclipsing binaries.

Read more: http://www.iflscience.com/space/ancient-egyptians-knew-about-distant-flashing-star-3000-years-earlier-thought