Why does the first LOAD segment offset 0x001000 instead of 0x00000 in ELF file？

Question

I got this question when I did the OS course lab. The linker script is used to link the object files to generate executable named kernel. ld -m elf_i386 -nostdlib -T tools/kernel.ld -o bin/kernel obj/kern/init/init.o Here is the script:

OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
OUTPUT_ARCH(i386)
ENTRY(kern_init)

SECTIONS {
    . = 0x100000;

    .text : {
        *(.text .stub .text.* .gnu.linkonce.t.*)
    }

    PROVIDE(etext = .); 

    .rodata : {
        *(.rodata .rodata.* .gnu.linkonce.r.*)
    }

    /* Include debugging information in kernel memory */
    .stab : {
        PROVIDE(__STAB_BEGIN__ = .);
        *(.stab);
        PROVIDE(__STAB_END__ = .);
        BYTE(0)     /* Force the linker to allocate space
                   for this section */
    }

    .stabstr : {
        PROVIDE(__STABSTR_BEGIN__ = .);
        *(.stabstr);
        PROVIDE(__STABSTR_END__ = .);
        BYTE(0)     /* Force the linker to allocate space
                   for this section */
    }

    /* Adjust the address for the data segment to the next page */
    . = ALIGN(0x1000);

    /* The data segment */
    .data : {
        *(.data)
    }

    PROVIDE(edata = .);

    .bss : {
        *(.bss)
    }

    PROVIDE(end = .);

    /DISCARD/ : {
        *(.eh_frame .note.GNU-stack)
    }
}

To understand the kernel program structure that is ELF format, with readelf -l kernel I got this list of segments:

Elf file type is EXEC (Executable file)
Entry point 0xc0100000
There are 3 program headers, starting at offset 52

Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
  LOAD           0x001000 0xc0100000 0xc0100000 0x16c8d 0x16c8d R E 0x1000
  LOAD           0x018000 0xc0117000 0xc0117000 0x02ae8 0x03a28 RW  0x1000
  GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RWE 0x10

 Section to Segment mapping:
  Segment Sections...
   00     .text .rodata .stab .stabstr
   01     .data .got.plt .data.rel.local .data.rel.ro.local .bss

Why does the first LOAD segment offset 0x001000 instead of 0x00000 in the ELF file？