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NASA spacecraft ready to launch through Sun’s burning atmosphere

reporter 1222 — Sat, 11 Aug 2018 07:00:48 +0000

The first ever spacecraft to fly directly toward the Sun is poised to blast off Saturday, on a mission to plunge into our star’s sizzling atmosphere and unlock the mysteries of the center of the solar system.

NASA’s car-sized, $1.5 billion Parker Solar Probe is scheduled to launch on a Delta IV Heavy rocket from Cape Canaveral, Florida during a 65-minute launch window that opens at 3:33 am (0733 GMT).

By coming closer to the Sun than any spacecraft in history, the unmanned probe’s main goal is to unveil the secrets of the corona, the unusual atmosphere around the Sun.

“We are going to be in an area that is so exciting, where solar wind — we believe — will be accelerating,” said NASA planetary science division director Jim Green.

“Where we see huge magnetic fields that are passing by us, as coronal mass ejections make their way out into the solar system.”

Not only is the corona about 300 times hotter than the Sun’s surface, but it also hurls powerful plasma and energetic particles that can unleash geomagnetic space storms, wreaking havoc on Earth by disrupting the power grid.

But these solar outbursts are poorly understood.

“The Parker Solar Probe will help us do a much better job of predicting when a disturbance in the solar wind could hit Earth,” said Justin Kasper, a project scientist and professor at the University of Michigan.

Knowing more about the solar wind and space storms will also help protect future deep space explorers as they journey toward the Moon or Mars.

– ‘Full of mysteries’ –

The probe is protected by an ultra-powerful heat shield that is just 4.5 inches (11.43 centimeters) thick.

The shield should enable the spacecraft to survive its close shave with the fiery star, coming within 3.83 million miles (6.16 million kilometers) of the Sun’s surface.

AFP / Gal ROMAProbing the sun

The heat shield is built to withstand radiation equivalent to up to about 500 times the Sun’s radiation on Earth.

Even in a region where temperatures can reach more than a million degrees Fahrenheit, the sunlight is expected to heat the shield to just around 2,500 degrees Fahrenheit (1,371 degrees Celsius).

Scorching, yes? But if all works as planned, the inside of the spacecraft should stay at just 85 degrees Fahrenheit.

The goal for the Parker Solar Probe is to make 24 passes through the corona during its seven-year mission.

“The sun is full of mysteries,” said Nicky Fox, project scientist at the Johns Hopkins University Applied Physics Lab.

“We are ready. We have the perfect payload. We know the questions we want to answer.”

– 91-year-old namesake –

The tools on board will measure the expanding corona and continually flowing atmosphere known as the solar wind, which solar physicist Eugene Parker first described in 1958.

Parker, now 91, recalled that at first some people did not believe in his theory.

But then, the launch of NASA’s Mariner 2 spacecraft in 1962 — becoming the first robotic spacecraft to make a successful planetary encounter — proved them wrong.

“It was just a matter of sitting out the deniers for four years until the Venus Mariner 2 spacecraft showed that, by golly, there was a solar wind,” Parker said earlier this week.

Parker said he was “impressed” by the Parker Solar Probe, calling it “a very complex machine.”

Scientists have wanted to build a spacecraft like this for more than 60 years, but only in recent years did the heat shield technology advance enough to be capable of protecting sensitive instruments, according to Fox.

Tools on board will measure high-energy particles associated with flares and coronal mass ejections, as well as the changing magnetic field around the Sun.

“We will also be listening for plasma waves that we know flow around when particles move,” Fox added.

“And last but not least, we have a white light imager that is taking images of the atmosphere right in front of the Sun.”

When it nears the Sun, the probe will travel rapidly enough to go from New York to Tokyo in one minute — some 430,000 miles per hour, making it the fastest human-made object.

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Sun’s Core Rotates 4 Times Faster Than Surface

reporter 1222 — Tue, 16 Jan 2018 13:45:44 +0000

TEHRAN – The sun’s core rotates nearly four times faster than its surface, an international team of astronomers found.

Scientists had assumed before that the core was rotating like a merry-go-round at about the same speed as the surface.

“The most likely explanation is that this core rotation is left over from the period when the sun formed, some 4.6 billion years ago,” said Roger Ulrich, a UCLA professor emeritus of astronomy, who has studied the sun’s interior for more than 40 years and co-author of the study that was published in the journal Astronomy and Astrophysics.

“It’s a surprise, and exciting to think we might have uncovered a relic of what the sun was like when it first formed,” he added.

The rotation of the solar core may give a clue to how the sun formed. After the sun formed, the solar wind likely slowed the rotation of the outer part of the sun, he said. The rotation might also impact sunspots, which also rotate, Ulrich said. Sunspots can be enormous; a single sunspot can even be larger than the Earth.

The researchers studied surface acoustic waves in the sun’s atmosphere, some of which penetrate to the sun’s core, where they interact with gravity waves that have a sloshing motion similar to how water would move in a half-filled tanker truck driving on a curvy mountain road. From those observations, they detected the sloshing motions of the solar core. By carefully measuring the acoustic waves, the researchers precisely determined the time it takes an acoustic wave to travel from the surface to the center of the sun and back again. That travel time turns out to be influenced a slight amount by the sloshing motion of the gravity waves, Ulrich said.

The core of the sun differs from its surface in another way as well. The core has a temperature of approximately 29 million degrees Fahrenheit, which is 15.7 million Kelvin. The sun’s surface is “only” about 30,000 degrees Fahrenheit, or 5,800 Kelvin.

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Over 7k plant samples returned to Iran

reporter 1222 — Mon, 25 Sep 2017 13:30:09 +0000

TEHRAN– Head of Iranian Biological Resource Center said Mon. that so far 7,200 plant samples that had been taken out of the country have returned home and are now being kept at the Center.

Hassan Shahzadeh Fazeli, head of Iranian Biological Resource Center, told Mehr News on Monday that the Center has been able to provide the most standard international conditions for preserving biological samples in the country’s biobank, adding “our measures have succeeded in gaining the trust of many foreign scientists in the world so that a number of foreign biological samples are currently being kept at the Iranian biobank.”

He went on to note that some samples do not exist in Iran, but are being kept in other countries, adding “at the moment, we are preserving some biological samples in the biobank that have been brought by tourists and which cannot be grown in Iran.”

According to Fazeli, some of Iranian samples are in the US and cannot be returned home due to sanctions; “as a result, we do not have accurate data on how many of our biological samples are currently kept in other countries,” he added.

“We are planning to return all domestic samples that have been taken out of the country by tourists or through any other method, and restore them in our own biobank,” he stressed.

According to Fazeli, by 2016, nearly 30,000 biological samples from plants, microorganisms, humans, animal, and molecules were stored in the country’s biobank.

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