Will Moon and Mars appear the same size this August?

On August 27, 2013, the moon and Mars are expected to appear the same size to the naked eye. That's how the story goes.In the astronomical world, this is called the 'Mars Hoax.'

It all started in 2003, writes Jeff Brush on SouthburyPatch.And here is the full story behind this.The distance between Earth and Mars varies dramatically over time. The maximum distance (when Earth and Mars are on opposite sides of the Sun) is about 250 million miles, and the minimum distance (Earth and Mars on the same side of the Sun, with Earth at its farthest distance from the Sun and Mars at its closest distance, is 33 million miles.

As a result, the apparent size of Mars does vary quite a bit, from a mere speck when seen through a typical telescope, to a small disk. When Mars is at its closest approach, the disk shows some level of detail of the surface of the planet, including large canyons and mountain ranges, though typically still quite blurry when viewed by eye through an amateur's telescope.

Mars comes within [approximately] 50 million miles of Earth once every 18 months or so. Because the orbit of Mars is more elliptical than Earth's orbit, it does occasionally get within 35 million miles, and the time between such closer approaches is measured in thousands of years.

The last closest approach occured on August 27, 2003 at 12:30 a.m. A couple months before that closest approach, a PowerPoint presentation posted on the Internet discussed the event. It is  mentioned therein that the next time Mars will be this close to Earth is in the year 2287, and, in big bold letters, "NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN".

As a result, every July and August since 2003, we see a recurrence of these emails or other Internet message types, carrying the same message. Will anyone live up to see this once-in-a-lifetime event? Mars isn't even visible in our nighttime sky this year (or in most of the years since 2003), concludes Brush.

To read more about this hoax, click here.

Comet ISON may pay a visit to the Red Planet

Around the world, astronomers are anticipating the approach of Comet ISON.A new ScienceCast video anticipates its close flyby of Mars on Oct. 1, 2013. On Thanksgiving Day 2013, the icy visitor from the outer solar system will skim the sun's outer atmosphere and, if it survives, could emerge as one of the brightest comets in years. First, though, it has to fly by Mars.

Astronomer Carey Lisse of the Johns Hopkins University Applied Physics Lab said,"Comet ISON is paying a visit to the Red Planet. On Oct 1st, the comet will pass within 0.07 AU from Mars, about six times closer than it will ever come to Earth."

Mars rovers and satellites will get a close-up view. It's too early to say whether Curiosity will be able to see the comet from the surface of Mars - that depends on how much ISON brightens between now and then. Lisse says the best bet is NASA's Mars Reconnaissance Orbiter. The MRO satellite is equipped with a powerful half-meter telescope named HiRISE that is more than capable of detecting the comet's atmosphere and tail. Observations are planned on four dates: August 20th, Sept 29th, and Oct 1st and 2nd.

The Mars flyby comes at a key time in Comet ISON's journey. It will have just crossed the "frost line," a place just outside the orbit of Mars where solar heating is enough to start vaporizing frozen water. But when ISON crosses the frost line, "the whole comet could erupt in geysers of gas," says Lisse. "Mars orbiters will have a ringside seat."

The amount of outgassing at Mars will give researchers clues to the size of ISON's nucleus, which is hidden from view deep within the comet's dusty atmosphere. McEwen sees this as a tune-up for another comet encounter next year. "The science value of observing Comet ISON is hard to predict. We've never tried such a thing before. However, this is good practice for Comet Siding Spring, which will pass much closer to Mars in 2014."

For now all eyes are on Comet ISON. An unprecedented number of NASA spacecraft - 16 - will be observing the comet. Astronauts on board the International Space Station will be watching, too.

To read more about the comet, click here.

Sun targets giant plumes of plasma towards the Earth

(The picture shows a corona mass ejection (CME) blowing out from just around the edge of the Sun, May 1, 2013. SOHO's C2 and C3 coronagraphs show a large, bright, circular cloud of particles heading out into space. CMEs carry over a billion tons of particles at over a million miles per hour. Courtesy of ESA & NASA / SOHO)

The sun fired off an intense solar storm at the Earth recently — the second in two days — hurtling billions of tons of charged particles at our planet, but it should not pose a threat to people on the ground, NASA says. The solar eruption, called a coronal mass ejection, occurred Wednesday at 1:24 a.m. ET and sent charged particles streaking outward at 380 miles per second. That's just over 1.3 million mph (2.2 million kilometers per hour). The solar fallout from the sun storm is expected to reach Earth within the next three days.

The solar storm on Wednesday erupted just 21 hours after another powerful coronal mass ejection (CME) on Tuesday. That solar tempest also sent billions of tons of solar particles on their way to Earth. "These particles cannot travel through the atmosphere to harm humans on Earth, but they can affect electronic systems in satellites and on the ground," NASA officials explained in a statement.

"Earth-directed CMEs can cause a space weather phenomenon called a geomagnetic storm, which occurs when they funnel energy into Earth's magnetic envelope, the magnetosphere, for an extended period of time," NASA officials said. "The CME’s magnetic fields peel back the outermost layers of Earth's fields, changing their very shape. In the past, geomagnetic storms caused by CMEs of this strength have usually been mild."

Powerful geomagnetic storms can affect communications signals and spark electrical surges in power grids. They can also supercharge northern lights displays or aurora observers at high latitudes. The sun is currently in an active phase of its 11-year solar weather cycle and is expected to reach its peak activity later this year. The current cycle is known as Solar Cycle 24.

To know more about CMEs and how they compare with solar flares, click here.

On new lava-filled planet years last for only 8.5 hours

Would you like to wake up to a new year every day? That’s exactly what you can do if you happen to be on an Earth-size fireball of a planet 700 light-years away, which orbits its star in just 8.5 hours. The newly discovered planet, named Kepler 78b, has one of the shortest orbital periods ever detected with a radius that is only about three times the radius of the star.Researchers believe that the planet is about 40 times closer to its star than Mercury is to our sun.

Scientists have estimated that the top layer of the planet is likely completely melted, creating a massive, rolling ocean of lava at temperatures at 2760°C. The star around which Kepler 78b orbits is likely relatively young, as it rotates more than twice as fast as the sun- a sign that the star has not had as much time to slow down.

But what has really excited astronomers is that they were able to detect light emitted by the planet.This is the first time researchers have been able to do so for an exoplanet as small as Kepler 78b, and it could give scientists detailed information about the planet’s surface composition and reflective properties.
Kepler 78b is so close to its star that scientists hope to measure its gravitational influence on the star.

To discover Kepler 78b, the team looked through more than 150,000 stars that were monitored by the Kepler Telescope, a NASA space observatory that surveys a slice of the galaxy. The researchers reported their discovery of Kepler 78b in The Astrophysical Journal.
In a separate paper, the same research team observed KOI 1843.03, a previously discovered exoplanet with an even shorter orbital period: just 4 1/4 hours.

In order for the planet to maintain its extremely tight orbit around its star, it would made almost entirely of iron, otherwise the immense tidal forces from the nearby star would rip the planet to pieces. Though Kepler has now been retired, scientists are still analysing data from it in hopes of identifying habitable, Earth-sized planets

Read more about the discovery and research here.

One-way trip to Mars? Sounds exciting!

Do you want to be part of an expedition to the Red Planet? You can be part of a one-way trip to Mars but you have to wait till 2022. Mars One is planning to send humans to the Red Planet and more than 100,000 have already applied for it. But only four individuals will be selected, according to the Dutch organization. The big question is: Will members of such an expedition, estimated to cost $6 billion, be able to survive the trip?

The Obama administration has set a goal to send astronauts to Mars by the 2030s – but Mars One is much more ambitious, looking to send the four people chosen to actually colonize the planet. Applications have poured in and Mars One recently announced the start of its selection program. They say they’ve already passed the 78,000 mark besides the fact that the registration fee ranges from $5 - 73, depending on the country.

However, a one-way trip to Mars would face an enormous number of technical and practical hurdles that aren’t close to being figured out. NASA’s intrepid rover Curiosity has started addressing one of the questions: radiation exposure on the journey.But the radiation challenges aren't insurmountable, according to scientists.

To know more about NASA's exploration and the risks involved in the journey, click here.

The sun's magnetic field is about to flip

Something big is about to happen on the sun... its vast magnetic field is about to flip! According to measurements from NASA-supported observatories, the sun's magnetic field changes polarity approximately every 11 years. It happens at the peak of each solar cycle as the sun's inner magnetic dynamo re-organizes itself.

The coming reversal will mark the midpoint of Solar Cycle 24. Half of 'Solar Max' will be behind us, with half yet to come. Solar physicist Todd Hoeksema of Stanford University said, "It looks like we're no more than 3 to 4 months away from a complete field reversal. This change will have ripple effects throughout the solar system." A new ScienceCast video anticipates the reversal of the sun's global magnetic field. You can watch it here.

Solar physicist Phil Scherrer, also at Stanford, describes what happens: "The sun's polar magnetic fields weaken, go to zero, and then emerge again with the opposite polarity. This is a regular part of the solar cycle." A reversal of the sun's magnetic field is, literally, a big event. The domain of the sun's magnetic influence (also known as the "heliosphere") extends billions of kilometers beyond Pluto. Changes to the field's polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space.

When solar physicists talk about solar field reversals, their conversation often centers on the "current sheet."  The current sheet is a sprawling surface jutting outward from the sun's equator where the sun's slowly-rotating magnetic field induces an electrical current.  The current itself is small, only one ten-billionth of an amp per square meter (0.0000000001 amps/m2), but there’s a lot of it: the amperage flows through a region 10,000 km thick and billions of kilometers wide.  Electrically speaking, the entire heliosphere is organized around this enormous sheet.

During field reversals, the current sheet becomes very wavy. Scherrer likens the undulations to the seams on a baseball.  As Earth orbits the sun, we dip in and out of the current sheet. Transitions from one side to another can stir up stormy space weather around our planet.

Cosmic rays are also affected. These are high-energy particles accelerated to nearly light speed by supernova explosions and other violent events in the galaxy.  Cosmic rays are a danger to astronauts and space probes, and some researchers say they might affect the cloudiness and climate of Earth. The current sheet acts as a barrier to cosmic rays, deflecting them as they attempt to penetrate the inner solar system. A wavy, crinkly sheet acts as a better shield against these energetic particles from deep space.

As the field reversal approaches, data from Wilcox show that the sun's two hemispheres are out of synch. "The sun's north pole has already changed sign, while the south pole is racing to catch up," says Scherrer. "Soon, however, both poles will be reversed, and the second half of Solar Max will be underway."

New Stellar System that 'blinks' every 93 days

Using data from NASA’s Spitzer Space telescope, scientists have discovered a young stellar system that 'blinks' every 93 days. This is the fourth example of a star system known to blink in such a manner, suggesting that these systems might be more common than previously thought.

U.S. astronomers using a NASA space telescope say they've spotted a young stellar system whose developing stars cause the system to 'blink'. The system is said to consist of three developing stars, two of which are surrounded by a disk of material left over from the star-formation process, according to scientists at the Jet Propulsion Laboratory in Pasadena, Calif.

As the two inner stars whirl around each other, astronomers said, they periodically peek out from the disk that girds them like a hula hoop, causing the cosmic "blink" witnessed by NASA's Spitzer Space Telescope.It is believed this disk should go on to spawn planets and the other celestial bodies that make up a solar system, astronomers said.The stellar system YLW 16A is the fourth example of a star system known to blink in such a manner.

Planets in such a system can orbit one or both of the stars in the binary star system; the famous science fiction planet Tatooine in "Star Wars" orbits two stars, and such worlds are referred to as circumbinary planets. Peter Plavchan, a scientist at the NASA Exoplanet Science Institute at the California Institute of Technology in Pasadena said, "These blinking systems offer natural probes of the binary and circumbinary planet formation process." 

Astronomers discover two heavy metal stars

A team of astronomers from Taiwan and the UK has discovered two unusual subdwarf stars with extremely high concentrations of lead in their atmospheres. These stars, labeled HE 2359-2844 and HE 1256-2738, have surfaces containing 10,000 times more lead than is present on the surface of the Sun, according to their paper published in the journal, Monthly Notices of the Royal Astronomical Society.

While the star HE 2359-2844 is a subdwarf located at a distance of 800 light years away in the constellation of Sculptor, HE 1256-2738 is located about 1,000 light years away in the constellation of Hydra.

The scientists using observations from the archives of the ESO’s Very Large Telescope in Chile identified a few features in spectra of both stars that did not match any atoms expected to be present. After some detective work, they realized that the features were due to lead, one of the heaviest naturally occurring elements. In the Sun there is less than one lead atom for every ten billion hydrogen atoms.

At around 38,000 degrees Celsius, the surfaces of HE 2359-2844 and HE 1256-2738 are so hot that three electrons are removed from every lead atom. The resulting ions produce distinctive lines in the star’s spectrum, from which the concentration of lead in the atmosphere can be measured. Using the same technique, HE 2359-2844 was also found to show ten thousand times more yttrium and zirconium than on the Sun. Along with the zirconium star LS IV-14 116, the newly discovered stars form a new group of ‘heavy metal subdwarfs.’

Study lead author Dr Naslim Neelamkodan from Armagh Observatory explains: “The heavy-metal stars are a crucial link between bright red giants, stars 30-40 times the size of the Sun, and faint blue subdwarfs, stars one-fifth the size, but seven times hotter and 70 times brighter than the Sun.”