April 12, 2018: Look Out Sun Here We Come!;
A close-up look at Earth’s brightest star.
By Mark Narwa.
Many of us do not realize it, but the Sun is actually a star. In fact, it is our nearest star, a glowing ball of gas that emits the heat and light which make it possible for us to survive here on Earth.
The Sun is 99.86% of the total mass of the solar system. Its mass is 73% hydrogen, 25% helium, and a combination of 2% carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur and iron.
The radius of the Sun is 695,700 km, which is 109 times larger than the Earth. Its mass is 1.99 x 10^30 kilograms (kg), which is 333,000 times the mass of the Earth. Its diameter is 1.39 million kilometres (km), And its distance from Earth is 149,600,000 km.
The Sun’s atmosphere consists of three layers. The photosphere, the chromosphere and the corona. The photosphere is the surface layer of the Sun’s atmosphere.
This layer is the visible surface of the Sun. It contains turbulent cells of gas called granules that transfer heat from the interior. This is where sunspots are visible and solar flares begin. This is also where the Sun’s energy is released as light. It takes that light about 8 minutes to travel the distance from the Sun to the Earth. Therefore, when we view the Sun, we are actually seeing it as it was 8 minutes ago.
The next layer above the photosphere is the chromosphere which emits a reddish glow, as extremely heated hydrogen is burned off. This red glow is visible only during a total solar eclipse.
Above the chromosphere is the third layer of the Sun’s atmosphere, the corona. It appears as white streamers or plumes of ionized gas that flow toward outer space. This layer too, can be seen only during a total solar eclipse.
This summer, NASA will be launching the “Parker Solar Probe” on a historic mission to study the Sun. The spacecraft itself is about the size of a small car. The Parker Solar Probe will travel directly into the Sun’s atmosphere, coming as close as 6.2 million km to the Sun’s surface. This will be the first spacecraft to get that close to the Sun’s surface, giving us the closest view of a star ever recorded.
While performing this mission, the Parker Solar Probe will encounter conditions of brutal heat and radiation. To protect the probe and instruments from the heat, the spacecraft will be shielded by a 4.5 inch carbon composite shield that can withstand outside temperatures of 1377 Celsius.
In order for the Parker Solar Probe to reach the Sun, it will use the gravitational pull of the planet Venus to assist it. The probe will make seven flybys of the planet Venus, over a seven year period to gradually bring it closer to the Sun’s orbit.
When the Parker Solar Probe reaches the Sun, it will fly into the part of the Sun’s outermost atmosphere, called the corona. While there, it will conduct scientific measurements and imaging to give us a better understanding of how the corona is heated, and study the origin and evolution of solar wind. This will give us a better understanding of space weather and how it can affect our planet earth.
Those interested can register at the NASA web site to have their names included on a micro-chip that will travel on the Parker Solar Probe. http://go.NASA.gov/HotTicket .
Photo Caption: Visit NASA at http://go.NASA.gov/HotTicket to send your name to the Sun with the Parker Solar Probe.
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