I believe your table would become a lot more readable if you transposed it and employed a longtable
environment to typeset it.

\documentclass{article}
\usepackage{booktabs,siunitx,longtable}
\usepackage[scr=zapfc]{mathalfa}
\begin{document}
\begin{longtable}{@{}
S[table-format=4.0]
S[table-format=4.0]S[table-format=3.2]
S[table-format=4.0]S[table-format=2.2] @{} }
\toprule
& \multicolumn{2}{c}{\textsc{Cu}}
& \multicolumn{2}{c@{}}{\textsc{Al}}\\
\cmidrule(lr){2-3} \cmidrule(l){4-5}
{Temperature} & {$\varrho$} & {$\mathscr{E}$}
& {$\varrho$} & {$\mathscr{E}$}\\
{[\si{\kelvin}]} & {[\si{\kilo\gram\per\meter\cubed}]}
& {[$10^9\,\si{\pascal}$]}
& {[\si{\kilo\gram\per\meter\cubed}]}
& {[$10^9\,\si{\pascal}$]}\\
\midrule
\endhead
\bottomrule
\endfoot
0 & 9028 & 137.0 & & 76.6 \\
10 & 9028 & 137.0 & & 76.59\\
{$\vdots$} & {$\vdots$} & {$\vdots$} & & {$\vdots$}\\
750 & 8718 & 98.30 & & 39.49 \\
{$\vdots$} & {$\vdots$} & {$\vdots$} \\
1250 & 8444 & 61.86 \\
\end{longtable}
\end{document}