Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Kepler-42
Table title:
Planetary system
Table:
<table id='hittask' contenteditable='False'>
<tr> <td colspan=1 rowspan=1 > Temperature comparisons </td><td colspan=1 rowspan=1 > Kepler-42c </td><td colspan=1 rowspan=1 > Kepler-42b </td><td colspan=1 rowspan=1 > Kepler-42d </td><td class="highlighted"  colspan=1 rowspan=1 > Earth </td></tr>
<tr> <td colspan=1 rowspan=1 > Global equilibrium temperature </td><td colspan=1 rowspan=1 > 728 K 455 °C 851 °F </td><td colspan=1 rowspan=1 > 524 K 251 °C 483.8 °F </td><td colspan=1 rowspan=1 > 454 K 181 °C 357.8 °F </td><td class="highlighted"  colspan=1 rowspan=1 > 255 K −18 °C −0.4 °F </td></tr>
<tr> <td colspan=5 rowspan=1 > References: </td></tr>
</table>
Question:
What is the Equilibrium temperature of Earth?
Answer:
The Equilibrium temperature of Earth is 255 K (−18 °C).