The Dark Stars - Revision history

Cosmo All at 11:29, 5 November 2013

2013-11-05T11:29:24Z

Cosmo All at 11:01, 4 October 2012

2012-10-04T11:01:09Z

Cosmo All at 11:00, 4 October 2012

2012-10-04T11:00:42Z

Cosmo All at 11:00, 4 October 2012

2012-10-04T11:00:08Z

Cosmo All: Created page with "7"

2012-10-02T10:48:08Z

Created page with "7"

New page

[[Category:Dark Matter|7]]

@@ Line 11: / Line 11: @@
 === Problem 1 ===
 Estimate how much will the period of rotation of the Earth around the Sun change in one year due to gravitational capture of dark matter particles.
-<div class="NavFrame collapsed">
+<!--<div class="NavFrame collapsed">
    <div class="NavHead">solution</div>
    <div style="width:100%;" class="NavContent">
      <p style="text-align: left;"></p>
    </div>
-</div></div>
+</div>--></div>

@@ Line 22: / Line 22: @@
 <div id=""></div>
 <div style="border: 1px solid #AAA; padding:5px;">
-=== Problem 1 ===
+=== Problem 2 ===
 Estimate the rate of energy outcome due to the WIMP-annihilation process using the parameter values $m_{WIMP}=100GeV$ and $\langle \sigma v \rangle_{ann}=3\cdot 10^{-26} cm^3/sec$ for the annihilation cross section.
 <div class="NavFrame collapsed">
@@ Line 38: / Line 38: @@
 <div id=""></div>
 <div style="border: 1px solid #AAA; padding:5px;">
-=== Problem 1 ===
+=== Problem 3 ===
 It is theorized that the dark matter particles' annihilation processes could be a competitive energy source in the first stars. Why did those processes play an important role only in the early Universe and why are they not important nowadays?
 <div class="NavFrame collapsed">

@@ Line 29: / Line 29: @@
      <p style="text-align: left;">WIMP-annihilation in unit volume produces produces amount of energy equal to
 \[Q_{ann}=\left<\sigma v\right>\rho_\chi^2/m_\chi\simeq 10^{-29}
-\frac{\mbox{\it erg}}{\mbox{\it cm}^3/\mbox{\it
+\frac{\mbox{erg}}{\mbox{cm}^3/\mbox{s}}\frac{\left<\sigma v\right>}{3\times 10^{-26}\mbox{cm}^3/\mbox{s}} \left(\frac{n}{\mbox{cm}^{-3}}\right)^{1,6}
-s}}\frac{\left<\sigma v\right>}{3\times 10^{-26}\mbox{\it
+\left(\frac{100\mbox{GeV}}{m_\chi}\right),\] where $\rho_\chi$ is the dark matter density inside the star and $n$ is that of hydrogen.</p>
-cm}^3/\mbox{\it s}} \left(\frac{n}{\mbox{\it cm}^{-3}}\right)^{1,6}
-\left(\frac{100\mbox{\it GeV}}{m_\chi}\right),\] where $\rho_\chi$ is the dark matter density inside the star and $n$ is that of hydrogen.</p>
    </div>
 </div></div>

← Older revision		Revision as of 11:00, 4 October 2012
Line 1:		Line 1:
	[[Category:Dark Matter\|7]]		[[Category:Dark Matter\|7]]
		+
		+	__NOTOC__
		+
		+
		+
		+
		+
		+	<div id=""></div>
		+	<div style="border: 1px solid #AAA; padding:5px;">
		+	=== Problem 1 ===
		+	Estimate how much will the period of rotation of the Earth around the Sun change in one year due to gravitational capture of dark matter particles.
		+	<div class="NavFrame collapsed">
		+	<div class="NavHead">solution</div>
		+	<div style="width:100%;" class="NavContent">
		+	<p style="text-align: left;"></p>
		+	</div>
		+	</div></div>
		+
		+
		+
		+	<div id=""></div>
		+	<div style="border: 1px solid #AAA; padding:5px;">
		+	=== Problem 1 ===
		+	Estimate the rate of energy outcome due to the WIMP-annihilation process using the parameter values $m_{WIMP}=100GeV$ and $\langle \sigma v \rangle_{ann}=3\cdot 10^{-26} cm^3/sec$ for the annihilation cross section.
		+	<div class="NavFrame collapsed">
		+	<div class="NavHead">solution</div>
		+	<div style="width:100%;" class="NavContent">
		+	<p style="text-align: left;">WIMP-annihilation in unit volume produces produces amount of energy equal to
		+	\[Q_{ann}=\left<\sigma v\right>\rho_\chi^2/m_\chi\simeq 10^{-29}
		+	\frac{\mbox{\it erg}}{\mbox{\it cm}^3/\mbox{\it
		+	s}}\frac{\left<\sigma v\right>}{3\times 10^{-26}\mbox{\it
		+	cm}^3/\mbox{\it s}} \left(\frac{n}{\mbox{\it cm}^{-3}}\right)^{1,6}
		+	\left(\frac{100\mbox{\it GeV}}{m_\chi}\right),\] where $\rho_\chi$ is the dark matter density inside the star and $n$ is that of hydrogen.</p>
		+	</div>
		+	</div></div>
		+
		+
		+
		+	<div id=""></div>
		+	<div style="border: 1px solid #AAA; padding:5px;">
		+	=== Problem 1 ===
		+	It is theorized that the dark matter particles' annihilation processes could be a competitive energy source in the first stars. Why did those processes play an important role only in the early Universe and why are they not important nowadays?
		+	<div class="NavFrame collapsed">
		+	<div class="NavHead">solution</div>
		+	<div style="width:100%;" class="NavContent">
		+	<p style="text-align: left;">Number of particles reproduced in the reactions of the dark matter particles annihilation is proportional to the latter's density squared. In early Universe the density was considerably higher than today.</p>
		+	</div>
		+	</div></div>