1.3 The Sun Flashcards
How can the sun be observed safely
Fitting the objective of a telescope with a h alpha filter or Mylar filter
The safest way is to use an indirect projection method in which a pinhole camera or a telescope focuses an enlarged image of the sun onto a screen which reduces the brightness level so that it is safe
What does 1 AU mean?
150 million KM and it’s the distance from Earth to the sun
What’s the Suns diameter?
1.4 million km
What’s the temperature of the Suns photosphere
5800k
What is the corona?
The outside glow of ionised gas - a faint luminous white ring
What temperature is the corona?
2 million kelvins
What’s the chromosphere
A gaseous layer above the photosphere
How hot is the chromosphere
4600k
What’s a sun spot?
Cooler areas on the photosphere that correspond to strong localised magnetic fields, these inhibit upward motion of convecting solar material and prevent it from reaching the top of photosphere resulting in lower temperatures
What’s the umbra of a sun spot?
A central darker and cool region of a sun spot, about 2000k cooler than photosphere
What’s the penumbra of a sun spot?
A less dark surround area of s sun spot with temperature of 200k cooler than photosphere
What’s the Suns rotation period
25 days at equator, 36 at the poles
How do we use sunspots to determine Suns rotation period
Observing a group of sunspots, recording there position and timing how many days it takes to return to the same position
What’s solar maximum
The most active time for sunspots - when there are most sunspots, last 5.5 years where often 100 sunspots visible at s time.
What’s solar minimum!
When it’s the calmest and least sunspots last first 5.5 years ones that are visible are short lived
Where do sun spots mainly appear
The cycle begins with sunspots 35 to 40 degrees north or south of solar equator, eventually progress to 5-10 degrees of the solar equator
How do we predict sunspots?
The solar cycle, an 11 year Chloe of the general pattern has been knows as a butterfly diagram which shows us frequency of sun spots
How does the sun shine? (What’s thermonuclear fusion)
It’s the source of the sun energy, in the core of sun the temperature of 15million k is so hot hydrogen nuclei fuse together to make helium nuclei and in each fusion energy is transferred and converted and radiates to the Suns photosphere where it then radiates outwards into space
E=mc^2
What does sun look like at different wavelengths
Visible light
H Alpha is a visible spectral line that’s can observe solar prominences and filaments. allows a narrow range of wavelengths either side of 657 nm to pass through
X-Ray’s are emitted form corona and allow us to understand further about Suns temperature
How does the sun look at different wave lengths
Visible - how we see it
H alpha - plane with crack and a few feature
X Ray - bursting out X Ray’s looks like a fireball
What is solar wind and what’s it like/ made of
A steady stream of charged particles mainly protons and electrons flowing outwards in all directions from Suns corona at speeds of 400km/s typical
The fast solar wind travels at 850km/s as it is believe to originate from coronal holes (cooler regions of corona) which allow particles to escape more easily
What’s the sun made of?
Hydrogen 75%
Helium 25%
How thick is the chromosphere?
2000KM
When can you observe the chromosphere
Can be observed a slender/ pink ring just before totality is reached during a solar eclipse
When can the corona be observed
In a solar eclipse the glowing region of ionised gas emits X Ray’s too
What’s the temperature of central core of the sun
15 million K
How fast do the solar winds travel?
Typical - 400km/s
Fast- 850km/
What’s a solar prominence
Huge clouds of cooler gas in the Suns atmosphere
What’s a filament
Same as prominence but appearing as dark silhouettes against the brighter photosphere
What’s a solar flares
Sudden releases of energy
