The center of Mars is most likely hot that might release Methane produced by bacteria.<p>"The core of mars is actually molten. The pressure there is 40 gigapascal. hat is 400,000 times the pressure of earth’s surface. The core is about 1500 degrees Kelvin, or 1230 Celsius."<p>There is bound to be an equilibrium between 1230C and the surface temperature<p>Surface temperature of Mars
Celsius −143 °C[12] −63 °C 35 °C<p>" 6° C per km"
<a href="https://astronomy.stackexchange.com/questions/14875/what-is-the-temperature-55-km-beneath-the-surface-of-mars" rel="nofollow">https://astronomy.stackexchange.com/questions/14875/what-is-...</a><p>6C*6km = 36C degrees Celsius at 6km depth which would be a favourable temperature for bacteria.<p>We have drilled a 12km on Earth in Russia Kola peninsula so we should be able to build a robotic oil drill platform send it To Mars and drill deep into the Mars core. The drill will have temperature
monitoring sensors.
<a href="https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole" rel="nofollow">https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole</a>
<a href="https://en.wikipedia.org/wiki/German_Continental_Deep_Drilling_Programme" rel="nofollow">https://en.wikipedia.org/wiki/German_Continental_Deep_Drilli...</a><p>"Methanogens have been found in several extreme environments on Earth – buried under kilometres of ice in Greenland and living in hot, dry desert soil. They are known to be the most common archaebacteria in deep subterranean habitats. Live microbes making methane were found in a glacial ice core sample retrieved from about three kilometres under Greenland by researchers from the University of California, Berkeley. They also found a constant metabolism able to repair macromolecular damage, at temperatures of 145C to –40C °"
<a href="https://en.wikipedia.org/wiki/Methanogen" rel="nofollow">https://en.wikipedia.org/wiki/Methanogen</a>