College aantekeningen
ASTRO 101: Black Holes Module 6
- Vak
- Instelling
Notes for ASTRO 101 based on the official Coursera videos for the class. Covers Module 6.
[Meer zien]Voorbeeld 2 van de 9 pagina's
Voorbeeld 2 van de 9 pagina's
In winkelwagen
In winkelwagen
Verkoper
Volgen
valladaressasha
Voorbeeld van de inhoud
Module 6Definitions:
● Event Horizon: A boundary that separates the insideof a black hole from the
outside, marking the point of no return for any material or light that crosses it.
● Comparison to Sun's Surface: Stars, like the Sun,don't have a defined surface,
but the outermost layer is called the photosphere, which we see in visible light.
Beyond this, there are faint layers like the chromosphere and corona.
● Black Hole Surface: Black holes don’t have a traditionalsurface but have an event
horizon, which is the defined boundary.
● Hydrostatic Equilibrium: The balance between gravitationalforce and gas
pressure in stars. Inside a black hole’s event horizon, gravity overwhelms gas
pressure, leading to a collapse.
● Gravitational Effects: Light is bent by the mass ofa black hole, similar to how a
ball’s path curves on a stretched sheet. The closer the light gets to the black hole,
the more it curves.
● Schwarzschild Radius: The radius of a non-rotatingblack hole’s event horizon,
which depends on the mass of the black hole. For the Sun, it’s 3 km, and it scales
linearly with the black hole’s mass.
● Black Hole Size and Mass: Larger black holes havelarger event horizons. The
event horizon of a black hole 15 times the mass of the Sun would be 45 km, while a
supermassive black hole’s event horizon could be millions of kilometers.
● Tidal Forces: For supermassive black holes, tidalforces are weaker, making them
safer for exploration. A black hole must be at least 1,000 times the Sun’s mass for a
safe visit.
● Photon Sphere: A region around a black hole wherelight can travel in unstable
circular orbits. This sphere is 1.5 times the size of the event horizon.
● Ring of Fire: The bright ring formed by photons trappedin circular orbits around a
black hole, seen by observers as light escapes the photon sphere.
● Black Hole Shadow: The dark region outside the eventhorizon, where no light
escapes, forming a shadow around the black hole.
● Gravitational Time Dilation: An astronaut fallinginto a black hole would
experience time normally, but an outside observer would see their time stretch
infinitely as they approach the event horizon.
● One-Way Nature of Event Horizon: The event horizonis a "one-way street" where
light can enter but cannot escape, making it difficult to observe what happens
inside.
, ● Danger of Crossing the Event Horizon: There's no visible marker for the event
horizon, making it easy to cross accidentally, but it's extremely dangerous due to
extreme tidal forces.
● Black Hole Interior: No information can escape frominside the event horizon, so
the interior remains a mystery. The singularity at the center is theorized to have
extreme physical properties.
● Cosmic Censorship Hypothesis: A theory that suggeststhe event horizon shields
us from seeing the singularity, a concept still under investigation in theoretical
physics.
The Singularity:
● Traveling Past the Event Horizon of a Black Hole:
○ Choose a supermassive black hole to avoid tidal forces.
○ Once past the event horizon, we enter the strange interior of a black hole.
○ Although we can't send information back to the universe, observers inside
can make scientific discoveries.
● Light and Space-Time Inside the Event Horizon:
○ Inside a black hole, it's not dark; light emitted from outside is still visible.
○ Any light inside the event horizon always points inward, towards the black
hole's singularity.
○ Radial distance and time dimensions switch roles inside the event horizon:
moving towards smaller radius values is akin to moving forward in time.
○ Escaping the black hole is impossible as this would require moving
backwards in time.
● Black Hole Interior and Space-Time Diagrams:
○ A collapsing star forms a black hole, represented by a time-space diagram.
○ The event horizon forms as the star collapses to the Schwarzschild radius.
○ Penrose diagrams help visualize the interior of black holes, highlighting
time and space dimensions.
● Time and Gravity Inside a Black Hole:
○ Once inside, objects inevitably move towards the singularity at r=0.
○ The time to fall from the event horizon to the singularity varies with black
hole mass.
○ For supermassive black holes, one could have hours to fall, while for
smaller ones, it’s just milliseconds.
Dit zijn jouw voordelen als je samenvattingen koopt bij Stuvia:
Bewezen kwaliteit door reviews
Studenten hebben al meer dan 850.000 samenvattingen beoordeeld. Zo weet jij zeker dat je de beste keuze maakt!
In een paar klikken geregeld
Geen gedoe — betaal gewoon eenmalig met iDeal, creditcard of je Stuvia-tegoed en je bent klaar. Geen abonnement nodig.
Direct to-the-point
Studenten maken samenvattingen voor studenten. Dat betekent: actuele inhoud waar jij écht wat aan hebt. Geen overbodige details!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper valladaressasha. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor $2.56. Je zit daarna nergens aan vast.
Is Stuvia te vertrouwen?
4,6 sterren op Google & Trustpilot (+1000 reviews)
Afgelopen 30 dagen zijn er 73429 samenvattingen verkocht
Opgericht in 2010, al 15 jaar dé plek om samenvattingen te kopen
Laatst bekeken door jou
Overig ·
Bio 210 Chapter 12 concept map
Samenvatting ·
Samenvatting Mechanica 6V
Tentamen (uitwerkingen) ·
CP Chem B Questions & Answers
College aantekeningen ·
Apuntes Primero Medicina
