Summary
Summary iGCSE Physics Pearson Edexcel Topic 8 Astrophysics Complete Notes
- Course
- Institution
iGCSE Physics Pearson Edexcel Topic 8 Astrophysics Complete Notes
[Show more]
Seller
Follow
anish24shah
Reviews received
Content preview
IGCSE PHYSICS – TOPIC 8ASTROPHYSICS
a) MOTION IN THE UNIVERSE
• EARTH – our planet, the Earth, is the third of eight planets in our
Solar System
• THE MILKY WAY GALAXY – our solar system is in the Milky Way galaxy
– a galaxy is a large collection of billions of stars
• GALAXY – a galaxy is a large collection of billions of stars
• UNIVERSE – a large collection of billions of galaxies, containing the
Milky Way and billions of other similar grouping called galaxies
• An objects gravitational field strength (g) depends on:
o The MASS OF THE OBJECT (the more the mass of something, the
stronger the gravity acting on it is)
o The DISTANCE FROM THE OBJECT (gravity gets weaker with
distance)
o This means that the value of the gravitational field strength (g) on
a planet or moon will differ
• For an object to orbit something there has to be a pulling force
towards that body – this is the GRAVITATIONAL ATTRATION of the
larger object. Gravitational force causes:
o Moons to orbit planets
o Planets to orbit the Sun
o Causes artificial satellites to orbit the Earth
o Causes comets to orbit the Sun
• PLANETS orbit the Sun in a SLIGHTLY ELLIPTICAL/NEARLY CIRCULAR
orbit.
o SIMILARITIES: They all orbit in the same plane. They all travel in
the same direction around the sun.
o DIFFERENCE: They orbit at different distances and different
speeds. They all take different amounts of time to orbit the Sun
51
, • The ORBIT OF COMETS is different to planets:
o There orbits are HIGHLY ELLIPTICAL (stretched)
o This causes the speed of the comets to change as the distance
form the Sun changed
o Comets do not orbit in the same plane or direction as planets
and can collide with planets or other comets as they travel at
different speeds
As the comet gets CLOSER
TO THE SUN, the force on it
due to gravity INCREASES so
it travels at a GREATER
SPEED. Also, as it gets closer
to the sun, its gravitational
potential energy
DECREASES by being
transferred to kinetic
energy. The INCREASE IN
KINETIC ENERGY means
there is an INCREASE IN
SPEED.
Orbital Speed = 2Pi x Orbital Radius/Time period
v = 2 x Pi x r/T
52
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller anish24shah. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.32. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75619 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now
Recently viewed by you
